A comparison between the treatment of low rectal cancer in Japan and the Netherlands, focusing on the patterns of local recurrence. Ann Surg. 2009;249:229-235. [PMID: 19212175 DOI: 10.1097/sla.0b013e318190a664]

Outcomes and failure patterns after chemoradiotherapy for locally advanced rectal cancer with positive lateral pelvic lymph nodes: a propensity score-matched analysis

PURPOSE

This study aimed to use propensity score matching (PSM) to explore the long-term outcomes and failure patterns in locally advanced rectal cancer (LARC) patients with positive versus negative lateral pelvic lymph node (LPLN).

MATERIALS AND METHODS

Patients with LARC were retrospectively divided into LPLN-positive and LPLN-negative groups. Clinical characteristics were compared between the groups using the chi-square test. PSM was applied to balance these differences. Progression-free survival (PFS) and overall survival (OS), and local-regional recurrence (LRR) and distant metastasis (DM) rates were compared between the groups using the Kaplan-Meier method and log-rank tests.

RESULTS

A total of 651 LARC patients were included, 160 (24.6%) of whom had positive LPLN and 491 (75.4%) had negative LPLN. Before PSM, the LPLN-positive group had higher rates of lower location (53.1% vs. 43.0%, P = 0.025), T4 stage (37.5% vs. 23.2%, P = 0.002), mesorectal fascia (MRF)-positive (53.9% vs. 35.4%, P < 0.001) and extramural venous invasion (EMVI)-positive (51.2% vs. 27.2%, P < 0.001) disease than the LPLN-negative group. After PSM, there were 114 patients for each group along with the balanced clinical factors, and both groups had comparable surgery, pathologic complete response (pCR), and ypN stage rates. The median follow-up was 45.9 months, 3-year OS (88.3% vs. 92.1%, P = 0.276) and LRR (5.7% vs. 2.8%, P = 0.172) rates were comparable between LPLN-positive and LPLN-negative groups. Meanwhile, despite no statistical difference, 3-year PFS (78.8% vs. 85.9%, P = 0.065) and DM (20.4% vs. 13.3%, P = 0.061) rates slightly differed between the groups. 45 patients were diagnosed with DM, 11 (39.3%) LPLN-positive and 3 (17.6%) LPLN-negative patients were diagnosed with oligometastases (P = 0.109).

CONCLUSIONS

Our study indicates that for LPLN-positive patients, there is a tendency of worse PFS and DM than LPLN-negative patients, and for this group patients, large samples are needed to further confirm our conclusion.

Identification of lateral pelvic nodes without metastasis in patients with rectal cancer treated with preoperative chemoradiotherapy or chemotherapy based on magnetic resonance imaging

Background

Intensive localized therapy is promising for the treatment of rectal cancer. In Japan, chemoradiotherapy (CRT) and neoadjuvant chemotherapy (NAC) are used as preoperative treatments for this disease. Magnetic resonance imaging (MRI) is used to diagnose lateral pelvic node (LPN) metastases, but the changes in LPN findings on MRI following preoperative treatment are unclear. Furthermore, there may be patients in whom LPN dissection can be omitted after CRT/NAC.

Methods

Patients who underwent total mesorectal excision with LPN dissection after CRT/NAC at 13 Japanese Society for Cancer of the Colon and Rectum member institutions between 2017 and 2019 were included. Changes in the short diameter of the LPNs after CRT/NAC and the reduction rate were examined.

Results

A total of 101 LPNs were examined in 28 patients who received CRT and 228 in 47 patients who received NAC. Comparison of LPNs before and after CRT/NAC showed that most LPNs shrank after CRT but that the size reduction was variable after NAC. Although some LPNs with a short diameter of <5 mm showed residual metastasis, no metastases were observed in LPNs that were <5 mm in short diameter before and after CRT/NAC and did not shrink after treatment.

Conclusion

Although the short diameter of LPNs was significantly reduced by both CRT and NAC, even LPNs with a short diameter of <5 mm could have residual metastases. However, dissection may be omitted for LPNs <5 mm in short diameter that do not shrink after preoperative CRT or NAC.

Comparison of short-term outcomes of laparoscopic surgery, robot-assisted laparoscopic surgery, and open surgery for lateral lymph-node dissection for rectal cancer: a network meta-analysis

This study attempted to compare short-term outcomes of laparoscopic surgery (LS), robot-assisted laparoscopic surgery (RS), and open surgery (OS) for lateral lymph-node dissection (LLND) in treatment of rectal cancer through network meta-analysis. Embase, Web of Science, PubMed, and The Cochrane Library databases were searched to collect cohort studies on outcomes of LS, RS, and OS for LLND for rectal cancer. Newcastle-Ottawa Scale (NOS) was utilized to evaluate the quality of cohort studies. Primary outcomes should at least include one of the following clinical outcome measures: operative time, blood loss, total lymph-node harvest, positive resection margin rate, postoperative complications, and postoperative hospital stay. A network meta-analysis was conducted using STATA software. Fourteen cohort studies including 8612 patients were eligible for inclusion. The network meta-analysis results showed that, in terms of intraoperative outcomes, the RS group had the longest operative time, while the OS group had the shortest; the LS and RS groups had significantly less blood loss than the OS group. In terms of histological outcomes, there were no significant differences in the total number of lymph nodes harvested and the positive margin rate among the LS, RS, and OS groups (P > 0.05). Regarding postoperative outcomes, the OS group had the highest probability of postoperative complications and the longest hospital stay, followed by the LS group, with the RS group being the lowest. RS was the best method in blood loss, postoperative complication rate, and postoperative hospital stay, followed by LS. OS had the shortest operative time and the highest blood loss.

The role of lateral pelvic lymph node dissection in advanced rectal cancer: a review of current evidence and outcomes

Metastatic lateral pelvic lymph nodes (LPNs) in rectal cancer significantly impact the prognosis and treatment strategies. Western practices emphasize neoadjuvant chemoradiotherapy (CRT), whereas Eastern approaches often rely on LPN dissection (LPND). This review examines the evolving role of LPND in the context of modern treatments, including total neoadjuvant therapy (TNT), and the impact of CRT on the management of clinically suspicious LPNs. We comprehensively reviewed the key literature comparing the outcomes of LPND versus preoperative CRT for rectal cancer, focusing on recent advancements and ongoing debates. Key studies, including the JCOG0212 trial and recent multicenter trials, were analyzed to assess the efficacy of LPND, particularly in conjunction with preoperative CRT or TNT. Current evidence indicates that LPND can reduce local recurrence rates compared to total mesorectal excision alone in patients not receiving radiation therapy. However, the benefit of LPND in the context of neoadjuvant CRT is influenced by the size and pretreatment characteristics of LPNs. While CRT can effectively control smaller metastatic LPNs, larger or clinically suspicious LPNs may require LPND for optimal outcomes. Advances in surgical techniques, such as robotic-assisted LPND, offer potential benefits but also present challenges and complications. The role of TNT in controlling metastatic LPNs and improving patient outcomes is emerging but remains underexplored. The decision to perform LPND should be individualized based on patient-specific factors, including LPN size, response to neoadjuvant treatment, and surgeon expertise. Future research should focus on optimizing treatment protocols and further evaluating the role of TNT in managing metastatic LPNs.

Efficacy of lateral lymph node dissection for local control of rectal cancer: A multicenter study

Background

This study aimed to evaluate the efficacy of lateral lymph node dissection (LLND) for rectal cancer by comparing the local control in patients with and without pathological lateral lymph node metastasis (LLNM).

Methods

We included 189 patients with rectal cancer who underwent total mesorectal excision and LLND at 13 institutions between 2017 and 2019. Patients with and without pathological LLNM were defined as the pLLNM (+) and (-) groups, respectively. Propensity score-matching helped to balance the basic characteristics of both groups. The incidences of local recurrence (LR) and lateral lymph node recurrence (LLNR) were compared between the groups.

Results

In the entire cohort, 39 of the 189 patients had pathological LLNM. The 3-year LR and LLNR rates were 18.3% and 4.0% (p = 0.01) and 7.7% and 3.3% (p = 0.22) in the pLLNM (+) and (-) groups, respectively. After propensity score matching, the data from 62 patients were analyzed. No significant differences in LR or LLNR were observed between both groups. The 3-year LR and LLNR rates were 16.4% and 9.8% (p = 0.46) and 9.7% and 9.8% (p = 0.99) in the pLLNM (+) and (-) groups, respectively.

Conclusion

LLND would lead to comparable local control in the pLLNM (+) and (-) groups if the clinicopathological characteristics except for LLNM are similar.

Anatomic Basis of Rectal Cancer Staging: Clarifying Controversies and Misconceptions

Rectal MRI provides a detailed depiction of pelvic anatomy; specifically, the relationship of the tumor to key anatomic structures, including the mesorectal fascia, anterior peritoneal reflection, and sphincter complex. However, anatomic inconsistencies, pitfalls, and confusion exist, which can have a strong impact on interpretation and treatment. These areas of confusion include the definition of the rectum itself, specifically differentiation of the rectum from the anal canal and the sigmoid colon, and delineation of the high versus low rectum. Other areas of confusion include the relative locations of the mesorectal fascia and peritoneum and their significance in staging and treatment, the difference between the mesorectal fascia and circumferential resection margin, involvement of the sphincter complex, and evaluation of lateral pelvic lymph nodes. The impact of these anatomic inconsistencies and sources of confusion is significant, given the importance of MRI in depicting the anatomic relationship of the tumor to critical pelvic structures, to triage surgical resection and neoadjuvant chemoradiotherapy with the goal of minimizing local recurrence. Evolving treatment paradigms also place MRI central in management of rectal cancer. ©RSNA, 2024.

Role of Lateral Pelvic Node Dissection in Rectal Cancer Surgery

The role of lateral pelvic lymph node dissection in the treatment of patients with locally advanced rectal cancer is a matter of controversy. Surgical practices in Korea and Japan have accepted this approach and are widely utilized; however, it is not routinely incorporated in the practice of countries in the Western hemisphere. This review will examine the role of lateral pelvic lymph node dissection.

Does Neoadjuvant Chemoradiotherapy Have an Additional Effect to Lateral Pelvic Lymph Node Dissection for Rectal Cancer?

Objectives

A total mesenteric excision (TME) with lateral pelvic lymph node dissection (LLND) is the standard treatment for advanced low rectal cancer in Japan. Recently, neoadjuvant (chemo)radiotherapy (n(C)RT) has been used with LLND to improve outcomes at multiple Japanese institutes. This study evaluates the benefits of adding nCRT to TME with LLND.

Methods

Seventy-two consecutive patients who underwent TME and LLND with or without nCRT between 2006-2019 to treat advanced low rectal cancer were retrospectively reviewed. The clinicopathological data were compared and the risk factors for local recurrence were evaluated.

Results

Fifty-seven patients (79.1%) underwent TME and LLND with nCRT, and 15 patients (20.9%) without nCRT. There was no significant difference in the clinicopathological characteristics except the clinical T stage. The occurrence of postoperative complications was statistically insignificant. The 5-year local recurrence rate of patients with nCRT was significantly lower than those without (4.0% versus 26.6%, in all patients, p=0.002). Multivariate analysis revealed that the absence of nCRT was an independent risk factor for local recurrences in patients who underwent TME with LLND (hazard ratio: 6.04, p=0.04).

Conclusions

The administration of nCRT prevented local recurrences more effectively in patients with advanced low rectal cancer who underwent TME with LLND.

Clinical influence of prophylactic lateral lymph node dissection on oncologic outcomes of patients with mid-low rectal cancer undergoing mesorectal excision: a meta-analysis

BACKGROUND

Although several recent meta-analyses have investigated the clinical influence of the addition of lateral lymph node dissection (LLND) on oncologic outcomes in patients with mid-low rectal cancer (RC) undergoing mesorectal excision (ME), most studies included in such meta-analyses were retrospectively designed. Therefore, this study aimed to explore the clinical influence of prophylactic LLND on oncologic outcomes in patients with mid-low RC undergoing ME.

METHODS

A comprehensive electronic search of the literature up to July 2022 was performed to identify studies that compared oncologic outcomes between patients with mid-low RC undergoing ME who underwent LLND and patients with mid-low RC undergoing ME who did not undergo LLND. A meta-analysis was performed using fixed-effects models and the generic inverse variance method to calculate hazard ratios (HRs) and 95% CIs, and heterogeneity was analyzed using I2 statistics.

RESULTS

A total of 6 studies, consisting of 3 randomized and 3 propensity score matching studies, were included in this meta-analysis. The results of the meta-analysis of 2 randomized studies demonstrated no significant effect of prophylactic LLND on improving oncologic outcomes concerning overall survival (OS) (HR, 1.22; 95% CI, 0.89-1.69; I2 = 0%; P = .22) and relapse-free survival (RFS) (HR, 1.03; 95% CI, 0.81-1.31; I2 = 28%; P = .83).

CONCLUSION

The results of this meta-analysis revealed no significant influence of prophylactic LLND on oncologic outcomes-OS and RFS-in patients with mid-low RC who underwent ME.

Management of Surgically Accessible Lymph Nodes Beyond Normal Resection Planes

This article discusses the management of isolated metastatic lymph nodes for colon and rectal cancer. There are traditionally significant differences in how certain regions of lymph nodes for colon and rectal cancer are managed in the East and West. This has led to the development of the lateral lymph node dissection for rectal cancer and extended lymphadenectomy techniques for colon cancer. This article will evaluate the literature on these techniques and what the surgical and oncological outcomes are at this time. In addition, colon and rectal cancers can occasionally have isolated distant lymph node metastases. These would traditionally be treated as systemic disease with chemotherapy. There is consideration though that these could be treated as similar to isolated liver or lung metastases which have been shown to be able to be treated surgically with good oncological results. The literature for these isolated distant lymph node metastases will be reviewed and treatment options available will be discussed.

The influence of neoadjuvant chemoradiotherapy combined with lateral lymph nodes dissection or not on the local recurrence of low to intermediate-stage II/III rectal cancer

BACKGROUND

Currently, the treatment options for stage II/III rectal cancer with preoperative lateral lymph nodes (LLN) enlargement are highly controversial between East and West, and the indications for diagnosing suspiciously positive enlarged LLN are inconsistent both nationally and internationally. Oriental scholars (especially Japanese) consider the LLN as a regional disease, they consider that prophylactic lateral lymph nodes dissection (LLND), regardless of whether the LLN is enlarged or not, is considered necessary if the tumor is found beneath the peritoneal reflex and invades the muscle layer. Western scholars regard LLN as distant metastases, recommending neoadjuvant chemoradiotherapy (nCRT) in conjunction with total rectal mesenteric resection (TME). In recent years, it has been found that neither of the two standard treatment regimens, East and West, significantly improved local control of tumors in patients with LLN enlargement. In contrast, nCRT combined with LLND significantly lowers the local recurrence (LR) rate. It has also been suggested that combination therapy regimens do not improve patient prognosis but increase treatment-related complications. Therefore, the suitable therapeutic option for rectal cancer with an enlarged LLN needs to be further explored.

AIM

Exploring appropriate treatment options for low to intermediate-stage II/III rectal cancer with LLN enlargement, as well as risk variables that may affect the LR in these patients with LLN enlarged.

METHODS AND PATIENTS

In this research, we retrospectively analyzed 110 patients with locally advanced mid-low (low boundary of tumor is no more than 10 cm from the anus) rectal cancer who were treated at Harbin Medical University Cancer Hospital arranged from 2017.1 to 2020.6. These patients had received nCRT and TME, and their initial rectal nuclear magnetic resonance imaging (MRI) revealed an enlarged LLN (short axis of LLN, SA ≥ 5 mm). Of these, 40 patients underwent LLND, thus, 110 patients were grouped into two groups: nCRT+TME (LLND-, n = 70) and nCRT+TME + LLND (LLND+, n = 40), and their 3 years prognoses were compared.

RESULTS

After a median follow-up of 49.0 months, the 3-year LR rate of the LLND- group was notably greater than the LLND+ group (22.8% vs. 7.5%, p = 0.04). However, there was no noteworthy difference in the 3-year progression-free survival (PFS, 70.5% vs. 77.5%, p > 0.05) rate or distant metastasis (DM) rate (20.0% vs. 17.5%, p > 0.05). Additionally, the LLND+ group experienced significantly more postoperative complications than the LLND- group (15.0% vs. 4.2%, p = 0.05). Subgroups analysis for the LLND- group revealed that patients with LLN short axis regression (ΔSA) > 35.9% after nCRT had significantly lower 3-year LR rate than patients with ΔSA ≤ 35.9% (9.1% vs. 35.1%, p = 0.01). Patients in the LLND- group with ΔSA > 35.9%, however, had comparable 3-year LR rate and DM rates to those in the LLND+ group.

CONCLUSION

LLN is an independent indicator for prognosis among people with low to intermediate-stage II/III malignant rectal tumors. Patients with poor SA regression (ΔSA ≤ 35.9%) after nCRT have a greater risk of positive LLN and a more substantial LR, and nCRT combined with LLND reduced the LR rate significantly, but considerably prolonged operative time, surgical bleeding, and postoperative complications. Patients with better SA regression (ΔSA > 35.9%), however, have a lower possibility of LR and might not need LLN clearance, in these cases, nCRT+TME is advised.

Lateral Lymph Node Dissection for Locally Advanced Rectal Carcinoma: A Step-by-Step Description of Surgical Anatomical Planes During Cadaveric Dissection and Minimally Invasive Surgery

PURPOSE

Total mesorectal excision (TME) is accepted as gold standard method in rectal cancer globally. But there is no standard for lateral lymph nodes. Combination of neoadjuvant treatment plus lateral lymph node dissection (LLND) in select patients might be a promising method. Our purpose is to describe the anatomic landmarks of LLND on cadavers and minimally invasive surgery.

MATERIALS AND METHODS

Local advanced rectal cancer and lateral lymph node (LLN) metastasis are accepted as an indication of neoadjuvant treatment. LLND was performed according to preoperative imaging after radiochemotherapy.

RESULTS

Twenty-eight (10.5%) of 267 patients with rectal cancer who had suspected lateral lymph node metastasis (LLNM) with magnetic resonance imaging (MRI) underwent LLND in addition to TME after neoadjuvant chemoradiotherapy. Eight of them had LLNM. Three patients had bilateral LLND and only 1 had LLNM. The median number of harvested lymph nodes was 6. The rates of LLNM increased with the presence of poor prognosis markers. One regional and 1 distant recurrence were detected in patients who had no LLN metastasis compared with2 regional and 4 distant recurrences in the LLN-positive group.

CONCLUSIONS

Local advanced rectal cancer cases may benefit from LLND, but it does not appear to have an effect on overall survival. There is no consensus whether size and/or morphologic criteria in MRI are the ideal guide for LLND.

Lateral Pelvic Nodal Management and Patterns of Failure in Patients Receiving Short-Course Radiation for Locally Advanced Rectal Cancer

BACKGROUND

Management of lateral pelvic lymph nodes in locally advanced rectal cancer is controversial, with limited data indicating the optimal approach. In addition, no data exist regarding the treatment of lateral nodes in the setting of short-course radiation and nonoperative intent.

OBJECTIVE

To evaluate a novel approach incorporating simultaneous integrated boost to suspicious lateral nodes.

DESIGN

A retrospective study.

SETTING

This study was conducted at a large tertiary referral center.

PATIENTS

Patients treated with radiation therapy and consolidation chemotherapy were included. All primary tumors underwent biopsy confirmation and disease staging with pelvic MRI.

INTERVENTIONS

Primary tumors were biopsy proven and staged with pelvic MRI. A subset of lateral pelvic lymph node patients received a simultaneous integrated boost of 35 Gy in 5 fractions. Then, chemotherapy was administered, with the majority receiving modified folinic acid, fluorouracil, and oxaliplatin. Clinical partial response required total mesorectal excision.

MAIN OUTCOME MEASURES

Patterns of failure and survival analyses by subgroup were assessed. Outcomes based on receipt of radiation were compared across node status.

RESULTS

Between January 2017 and January 2022, 155 patients were treated with short-course chemotherapy, with 121 included in the final analysis. Forty-nine percent of patients underwent nonoperative management. The median follow-up was 36 months and the median age was 58 years. Thirty-eight patients (26%) had positive lateral pelvic lymph nodes. Comparing lateral node status, progression-free survival was significantly worse for patients with positive disease ( p < 0.001), with a trend for worse overall survival. Receipt of nodal boost in patients with lateral nodes resulted in meaningful locoregional control. Nodal boost did not contribute to additional acute or late GI toxicity.

LIMITATIONS

Limitations include retrospective nature and lack of lateral node pathology; however, a thorough radiographic review was performed.

CONCLUSIONS

Lateral node-positive rectal cancer is correlated with worse oncologic outcomes and higher locoregional failure. Boost to clinically positive lateral nodes is a safe approach in the setting of short course radiation and in those receiving nonoperative intent. See Video Abstract.

MANEJO DE LOS GANGLIOS PLVICOS LATERALES Y PATRONES DE FALLA EN PACIENTES QUE RECIBEN RADIACIN DE CICLO CORTO PARA EL CNCER DE RECTO LOCALMENTE AVANZADO

ANTECEDENTES:El manejo de los ganglios linfáticos pélvicos laterales en el cáncer de recto localmente avanzado es controvertido, con datos limitados que indiquen el abordaje óptimo. Además, no existen datos sobre el tratamiento de los ganglios linfáticos laterales en el contexto de la radiación de curso corto y la intención no operatoria.OBJETIVO:Evaluamos un enfoque novedoso que incorpora sobreimpresión integrada simultánea (SIB) a los linfonodos laterales sospechosos.DISEÑO:Este fue un estudio retrospectivo.ESCENARIO:Este estudio se realizó en un gran centro de referencia terciario.PACIENTES:Se incluyeron pacientes tratados con radiación y quimioterapia de consolidación. Todos los tumores primarios se confirmaron mediante biopsia y la enfermedad se estadificó con resonancia magnética pélvica.INTERVENCIONES:Los tumores primarios se confirmaron mediante biopsia y se estadificaron con RM pélvica. Un subconjunto de pacientes con linfonodos pélvicos laterales (LPLN) recibió SIB a 35 Gy en 5 fracciones. Luego, se administró quimioterapia y la mayoría recibió mFOLFOX. La respuesta clínica parcial requirió la escisión total del mesorrecto.PRINCIPALES MEDIDAS DE RESULTADO:Se evaluaron los patrones de fracaso y los análisis de supervivencia por subgrupo. Los resultados basados en el esquema de radiación se compararon según el estado de los ganglios.RESULTADOS:Entre enero de 2017 y enero de 2022, 155 pacientes fueron tratados con ciclo corto y quimioterapia con 121 incluidos en el análisis final. El 49% se sometió a manejo no operatorio. La mediana de seguimiento fue de 36 meses y la mediana de edad fue de 58 años. 38 pacientes (26%) tuvieron LPLN positivos. Comparando el estado de los ganglios laterales, la supervivencia libre de progresión fue significativamente peor para los pacientes con LPLN positiva ( p < 0,001) con una tendencia a una peor supervivencia global. La recepción de refuerzo nodal en pacientes con nodos laterales dio como resultado un control locorregional significativo. La sobreimpresión ganglionar no contribuyó a la toxicidad GI aguda o tardía adicional.LIMITACIONES:Las limitaciones incluyeron la naturaleza retrospectiva y la falta de patología de los ganglios linfáticos laterales; sin embargo, se realizó una revisión radiográfica exhaustiva.CONCLUSIONES:El cáncer de recto con ganglio lateral positivo se correlaciona con peores resultados oncológicos y mayor fracaso locorregional. La sobreimpresión a los ganglios laterales clínicamente positivos es un enfoque seguro en el contexto de un curso corto y en aquellos que siguen un manejo no operatorio. (Traducción-Dr. Felipe Bellolio ).

Current perspectives on the management of lateral pelvic lymph nodes in rectal cancer

Significant controversies exist with regards to the optimal management of lateral pelvic lymph nodes metastases (mLLN) in patients with low rectal cancer. The differing views held by Japanese and Western clinicians on the management of mLLN have been well documented. However, the adequacy of pelvic lymph node dissection (PLND) or neoadjuvant chemoradiation (NACRT) alone in addition to total mesorectal excision (TME) have recently come into question, due to the relatively high incidence of lateral local recurrences following PLND and TME, or NACRT and TME alone. Recently, a more selective approach to PLND has been suggested, involving a combination of neoadjuvant therapy, followed by PLND only to patients in whom the oncological benefit is likely to outweigh the risk of potential adverse events. A number of studies have attempted to retrospectively identify certain nodal characteristics on preoperative imaging, such as nodal size, appearance, and size reduction following neoadjuvant therapy. However, no consensus has been reached regarding the optimal criteria for a selective approach to PLND, partly due to the heterogeneity and retrospective nature of most of these studies. This review aims to provide an overview of recent evidence with regards to the diagnostic challenges, considerations for, and outcomes of the current management strategies for mLLN in rectal cancer patients.

Development of a Diagnostic Artificial Intelligence Tool for Lateral Lymph Node Metastasis in Advanced Rectal Cancer

BACKGROUND

Metastatic lateral lymph node dissection can improve survival in patients with rectal adenocarcinoma, with or without chemoradiotherapy. However, the optimal imaging diagnostic criteria for lateral lymph node metastases remain undetermined.

OBJECTIVE

To develop a lateral lymph node metastasis diagnostic artificial intelligence tool using deep learning, for patients with rectal adenocarcinoma who underwent radical surgery and lateral lymph node dissection.

DESIGN

Retrospective study.

SETTINGS

Multicenter study.

PATIENTS

A total of 209 patients with rectal adenocarcinoma, who underwent radical surgery and lateral lymph node dissection at 15 participating hospitals, were enrolled in the study and allocated to training (n = 139), test (n = 17), or validation (n = 53) cohorts.

MAIN OUTCOME MEASURES

In the neoadjuvant treatment group, images taken before pretreatment were classified as baseline images and those taken after pretreatment as presurgery images. In the upfront surgery group, presurgery images were classified as both baseline and presurgery images. We constructed 2 types of artificial intelligence, using baseline and presurgery images, by inputting the patches from these images into ResNet-18, and we assessed their diagnostic accuracy.

RESULTS

Overall, 124 patients underwent surgery alone, 52 received neoadjuvant chemotherapy, and 33 received chemoradiotherapy. The number of resected lateral lymph nodes in the training, test, and validation cohorts was 2418, 279, and 850, respectively. The metastatic rates were 2.8%, 0.7%, and 3.7%, respectively. In the validation cohort, the precision-recall area under the curve was 0.870 and 0.963 for the baseline and presurgery images, respectively. Although both baseline and presurgery images provided good accuracy for diagnosing lateral lymph node metastases, the accuracy of presurgery images was better than that of baseline images.

LIMITATIONS

The number of cases is small.

CONCLUSIONS

An artificial intelligence tool is a promising tool for diagnosing lateral lymph node metastasis with high accuracy.

DESARROLLO DE UNA HERRAMIENTA DE INTELIGENCIA ARTIFICIAL PARA EL DIAGNSTICO DE METSTASIS EN GANGLIOS LINFTICOS LATERALES EN CNCER DE RECTO AVANZADO

ANTECEDENTES:Disección de nódulos linfáticos laterales metastásicos puede mejorar la supervivencia en pacientes con adenocarcinoma del recto, con o sin quimiorradioterapia. Sin embargo, aún no se han determinado los criterios óptimos de diagnóstico por imágenes de los nódulos linfáticos laterales metastásicos.OBJETIVO:Nuestro objetivo fue desarrollar una herramienta de inteligencia artificial para el diagnóstico de metástasis en nódulos linfáticos laterales mediante el aprendizaje profundo, para pacientes con adenocarcinoma del recto que se sometieron a cirugía radical y disección de nódulos linfáticos laterales.DISEÑO:Estudio retrospectivo.AJUSTES:Estudio multicéntrico.PACIENTES:Un total de 209 pacientes con adenocarcinoma del recto, que se sometieron a cirugía radical y disección de nódulos linfáticos laterales en 15 hospitales participantes, se inscribieron en el estudio y se asignaron a cohortes de entrenamiento (n = 139), prueba (n = 17) o validación (n = 53).PRINCIPALES MEDIDAS DE RESULTADO:En el grupo de tratamiento neoadyuvante, las imágenes tomadas antes del tratamiento se clasificaron como imágenes de referencia y las posteriores al tratamiento, como imágenes previas a la cirugía. En el grupo de cirugía inicial, las imágenes previas a la cirugía se clasificaron como imágenes de referencia y previas a la cirugía. Construimos dos tipos de inteligencia artificial, utilizando imágenes de referencia y previas a la cirugía, ingresando los parches de estas imágenes en ResNet-18. Evaluamos la precisión diagnóstica de los dos tipos de inteligencia artificial.RESULTADOS:En general, 124 pacientes se sometieron a cirugía solamente, 52 recibieron quimioterapia neoadyuvante y 33 recibieron quimiorradioterapia. El número de nódulos linfáticos laterales removidos en los cohortes de entrenamiento, prueba y validación fue de 2,418; 279 y 850, respectivamente. Las tasas metastásicas fueron 2.8%, 0.7%, y 3.7%, respectivamente. En el cohorte de validación, el área de recuperación de precisión bajo la curva fue de 0.870 y 0.963 para las imágenes de referencia y antes de la cirugía, respectivamente. Aunque tanto las imágenes previas a la cirugía como las iniciales proporcionaron una buena precisión para diagnosticar metástasis en los nódulos linfáticos laterales, la precisión de las imágenes previas a la cirugía fue mejor que la de las imágenes iniciales.LIMITACIONES:El número de casos es pequeño.CONCLUSIÓN:La inteligencia artificial es una herramienta prometedora para diagnosticar metástasis en los nódulos linfáticos laterales con alta precisión. (Traducción-Dr. Aurian Garcia Gonzalez ).

Essential anatomy for lateral lymph node dissection

In Western countries, the gold-standard therapeutic strategy for rectal cancer is preoperative chemoradiotherapy (CRT) following total mesorectal excision (TME), without lateral lymph node dissection (LLND). However, preoperative CRT has recently been reported to be insufficient to control lateral lymph node recurrence in cases of enlarged lateral lymph nodes before CRT, and LLND is considered necessary in such cases. We performed a literature review on aspects of pelvic anatomy associated with rectal surgery and LLND, and then combined this information with our experience and knowledge of pelvic anatomy. In this review, drawing upon research using a 3-dimensional anatomical model and actual operative views, we aimed to clarify the essential anatomy for LLND. The LLND procedure was developed in Asian countries and can now be safely performed in terms of functional preservation. Nonetheless, the longer operative time, hemorrhage, and higher complication rates with TME accompanied by LLND than with TME alone indicate that LLND is still a challenging procedure. Laparoscopic or robotic LLND has been shown to be useful and is widely performed; however, without a sufficient understanding of anatomical landmarks, misrecognition of vessels and nerves often occurs. To perform safe and accurate LLND, understanding the landmarks of LLND is essential.

Coverage of Lateral Lymph Nodes in Rectal Cancer Patients with Routine Radiation Therapy Practice and Associated Locoregional Recurrence Rates

PURPOSE

Involved internal iliac and obturator lateral lymph nodes (LLNs) are a known risk factor for the occurrence of ipsilateral local recurrences (LLR) in rectal cancer. This study examined coverage of LLNs with routine radiation therapy practice in the Netherlands and associated LLR rates.

METHODS AND MATERIALS

Patients with a primary tumor ≤8 cm of the anorectal junction, cT3-4 stage, and at least 1 internal iliac or obturator LLN with short axis ≥5 mm who received neoadjuvant (chemo)radiation therapy, were selected from a national, cross-sectional study of patients with rectal cancer treated in the Netherlands in 2016. Magnetic resonance images and radiation therapy treatment plans were reviewed regarding segmented LLNs as gross tumor volume (GTV), location of LLNs within clinical target volume (CTV), and received proportion of the planned radiation therapy dose.

RESULTS

A total of 223 out of 3057 patients with at least 1 LLN ≥5 mm were selected. Of those, 180 (80.7%) LLNs were inside the CTV, of which 60 (33.3%) were segmented as GTV. Overall, 202 LLNs (90.6%) received ≥95% of the planned dose. Four-year LLR rates were not significantly higher for LLNs situated outside the CTV compared with those inside (4.0% vs 12.5%, P = .092) or when receiving <95% versus ≥95% of the planned radiation therapy dose (7.1% vs 11.3%, P = .843), respectively. Two of 7 patients who received a dose escalation of 60 Gy developed an LLR (4-year LLR rate of 28.6%).

CONCLUSIONS

This evaluation of routine radiation therapy practice showed that adequate coverage of LLNs was still associated with considerable 4-year LLR rates. Techniques resulting in better local control for patients with involved LLNs need to be explored further.

Lateral lymph node involvement presents another challenge in rectum cancer in the age of neoadjuvant chemoradiotherapy + total mesorectal excision: an evaluation of survival outcomes

PURPOSE

In the last decades, total mesorectal excision (TME) and neoadjuvant chemoradiotherapy (nCRT) have produced an undeniable improvement in the treatment of rectal cancer. However, local recurrence is still an important problem, and the effect of lateral lymph node (LLN) involvement on local recurrence is a controversial issue. The aim of this study was to investigate the effects of LLN status on local recurrence and survival in rectal cancers treated with nCRT + TME.

METHODS

Clinical features, pre- and post-nCRT lateral pelvic region imaging, long-term local recurrence, and the survival outcomes of 114 patients who underwent nCRT + TME for rectal cancer were evaluated.

RESULTS

On MRI before nCRT, 20 (17.5%) patients had lateral lymph nodes (LLN+), and 94 (82.5%) patients had no lymph nodes in the lateral pelvic compartments (LLN-). Local recurrences at 1 year in LLN+ and LLN- patients were 3 (15.8%) and 2 (2.3%), respectively (p=0.039). Five-year local recurrence-free survival rates and the mean duration of recurrence-free survival in LLN+ and LLN- patients were 56.2%, 42.6 months, and 87.3% 66.9 months, respectively (p=0.001). Disease-free survival and overall survival were shorter in LLN+ patients, but the difference was not statistically significant (p=0.096 and p=0.46, respectively). In the multivariate analysis, LLN involvement was determined to be an independent risk factor for local recurrence-free survival (Hazard Ratio 4.54, p=0.003).

CONCLUSION

Lateral lymph node involvement causes local recurrence to remain high after nCRT + TME. LLN status should be considered in treatment planning. Further studies are needed to define precise criteria for LLN involvement and the effect of LLND on local recurrence and survival.

Risk factors for lateral pelvic lymph node metastasis in patients with lower rectal cancer: a systematic review and meta-analysis

Background and objective

Lateral pelvic lymph node (LPLN) metastasis is one of the prominent reasons for local recurrence (LR) in patients with rectal cancer (RC). The evaluation criteria of lateral lymph node dissection (LLND) for patients in eastern (mainly in Japan) and western countries have been controversial. The aim of this study was to analyse the risk factors for LPLN metastasis in order to guide surgical methods.

Methods

We searched relevant databases (Embase (Ovid), Medline (Ovid), PubMed, Cochrane Library, and Web of Science) for articles published between 1 January 2000 and 05 October 2022 to evaluate the risk factors for LPLN metastasis in patients with RC in this meta-analysis.

Results

A total of 24 articles with 5843 patients were included in this study. The overall results showed that female sex, age <60 years, pretherapeutic CEA level >5 ng/ml, clinical T4 stage (cT4), clinical M1 stage (cM1), distance of the tumour from the anal verge (AV) <50 mm, tumour centre located below the peritoneal reflection (Rb), short axis (SA) of LPLN ≥8 mm before nCRT, short axis (SA) of LPLN ≥5 mm after nCRT, border irregularity of LPLN, tumour size ≥50 mm, pathological T3-4 stage (pT3-4), pathological N2 stage (pN2), mesorectal lymph node metastasis (MLNM), lymphatic invasion (LI), venous invasion (VI), CRM (+) and poor differentiation were significant risk factors for LPLN metastasis (P <0.05).

Conclusion

This study summarized almost all potential risk factors of LPLN metastasis and expected to provide effective treatment strategies for patients with LRC. According to the risk factors of lateral lymph node metastasis, we can adopt different comprehensive treatment strategies. High-risk patients can perform lateral lymph node dissection to effectively reduce local recurrence; In low-risk patients, we can avoid overtreatment, reduce complications and trauma caused by lateral lymph node dissection, and maximize patient survival and quality of life.

Key clinical trials in rectal cancer shaping the current treatment paradigms: reference guide for radiologists

Total neoadjuvant therapy (TNT), which includes chemotherapy and radiation prior to surgical resection, has been recently accepted as the new standard of care for patients with locally advanced low and mid rectal cancers. Multiple clinical trials have evaluated this approach in the last several decades and demonstrated improvement in, local control and reduced risk of recurrence. In addition, in the course of these investigations, it has been shown that between a third and a half of patients experience a clinical complete response (cCR) after being treated with the TNT approach, leading to the development of new organ preservation protocol, now known as watch-and-wait (W&W). On this protocol, cCR patients are not referred for surgery after total neoadjuvant treatment. Instead, they remain on close surveillance and, thus, avoid potential complications associated with surgical resection. Multiple clinical trials are ongoing, investigating the long-term outcomes of these new approaches and the development of less toxic and more effective TNT regimens for LARC. Improvements in technology and rectal MRI protocols position radiologists as vital members of multidisciplinary rectal cancer management teams. Rectal MRI has become a critical tool for rectal cancer initial staging, treatment response assessment, and surveillance on W&W protocols. In this review, we summarize the findings of the pivotal clinical trials that contributed to establishing the current treatment paradigms in locally advanced rectal cancer (LARC) management, with the intention of helping radiologists play more effective roles in their multidisciplinary teams.

Evaluation of National Surgical Practice for Lateral Lymph Nodes in Rectal Cancer in an Untrained Setting

BACKGROUND

Involved lateral lymph nodes (LLNs) have been associated with increased local recurrence (LR) and ipsi-lateral LR (LLR) rates. However, consensus regarding the indication and type of surgical treatment for suspicious LLNs is lacking. This study evaluated the surgical treatment of LLNs in an untrained setting at a national level.

METHODS

Patients who underwent additional LLN surgery were selected from a national cross-sectional cohort study regarding patients undergoing rectal cancer surgery in 69 Dutch hospitals in 2016. LLN surgery consisted of either 'node-picking' (the removal of an individual LLN) or 'partial regional node dissection' (PRND; an incomplete resection of the LLN area). For all patients with primarily enlarged (≥7 mm) LLNs, those undergoing rectal surgery with an additional LLN procedure were compared to those  undergoing only rectal resection.

RESULTS

Out of 3057 patients, 64 underwent additional LLN surgery, with 4-year LR and LLR rates of 26% and 15%, respectively. Forty-eight patients (75%) had enlarged LLNs, with corresponding recurrence rates of 26% and 19%, respectively. Node-picking (n = 40) resulted in a 20% 4-year LLR, and a 14% LLR after PRND (n = 8; p = 0.677). Multivariable analysis of 158 patients with enlarged LLNs undergoing additional LLN surgery (n = 48) or rectal resection alone (n = 110) showed no significant association of LLN surgery with 4-year LR or LLR, but suggested higher recurrence risks after LLN surgery (LR: hazard ratio [HR] 1.5, 95% confidence interval [CI] 0.7-3.2, p = 0.264; LLR: HR 1.9, 95% CI 0.2-2.5, p = 0.874).

CONCLUSION

Evaluation of Dutch practice in 2016 revealed that approximately one-third of patients with primarily enlarged LLNs underwent surgical treatment, mostly consisting of node-picking. Recurrence rates were not significantly affected by LLN surgery, but did suggest worse outcomes. Outcomes of LLN surgery after adequate training requires further research.

Lateral Lymph Node Size and Tumor Distance From Anal Verge Accurately Predict Positive Lateral Pelvic Lymph Nodes in Rectal Cancer: A Multi-Institutional Retrospective Cohort Study

BACKGROUND

Lateral pelvic lymph node dissection improves oncological outcomes in rectal cancer patients with suspected lateral pelvic lymph node metastasis. However, the indication for this procedure remains unclear.

OBJECTIVE

This study aimed to identify the predictive factors for lateral lymph node metastasis and the indications for lateral pelvic lymph node dissection.

DESIGN

A multi-institutional retrospective study.

SETTINGS

This study was conducted at 3 university hospitals.

PATIENTS

This study involved 105 patients with locally advanced mid/low rectal cancer and clinically suspected lateral pelvic lymph node metastasis who underwent total mesorectal excision with lateral pelvic lymph node dissection between 2015 and 2020.

MAIN OUTCOME MEASURES

Indications were set using lateral pelvic lymph node metastasis-associated preoperative factors.

RESULTS

Among 105 patients, 36 (34.3%) had pathologically confirmed lateral pelvic lymph node metastasis and 77 (73.3%) underwent preoperative chemoradiation. Tumors located within 5 cm distance from the anal verge ( p = 0.02) and initial node size ≥ 6 mm ( p = 0.001) were significant predictors of lateral pelvic lymph node metastasis. The sensitivity was 100% (36/36) with a cutoff of 6 mm for the initial node size and 94.4% (34/36) with a cutoff of 8 mm for the initial node size. When using initial node size cutoffs of 8 mm for anal verge-to-tumor distance of >5 cm and 6 mm for anal verge-to-tumor distance of ≤5 cm, the sensitivity of lateral pelvic lymph node metastasis was found to be 100%.

LIMITATIONS

The retrospective design and small sample size were the limitations of this study.

CONCLUSION

Initial node size and tumor height were significant predictors of lateral pelvic lymph node metastasis. This study proposed that an initial node size of ≥8 mm with an anal verge-to-tumor distance of >5 cm and ≥6 mm with an anal verge-to-tumor distance of ≤5 cm are optimal indications for lateral pelvic lymph node dissection in rectal cancer. See Video Abstract at http://links.lww.com/DCR/C101 .

EL TAMAO DEL GANGLIO LINFTICO LATERAL Y LA DISTANCIA DEL TUMOR DESDE EL BORDE ANAL PREDICEN CON PRECISIN LOS GANGLIOS LINFTICOS PLVICOS LATERALES POSITIVOS EN EL CNCER DE RECTO UN ESTUDIO DE COHORTE RETROSPECTIVO MULTIINSTITUCIONAL

ANTECEDENTES:La disección de los ganglios linfáticos pélvicos laterales mejora los resultados oncológicos en pacientes con cáncer de recto con sospecha de metástasis en los ganglios linfáticos pélvicos laterales. Sin embargo, la indicación de este procedimiento sigue sin estar clara.OBJETIVO:Nuestro objetivo fue identificar los factores predictivos de la metástasis de los ganglios linfáticos laterales y las indicaciones para la disección de los ganglios linfáticos pélvicos laterales.DISEÑO:Estudio retrospectivo multiinstitucional.AJUSTES:Este estudio se realizó en tres hospitales universitarios.PACIENTES:Este estudio involucró a 105 pacientes con cáncer de recto medio/bajo localmente avanzado y sospecha clínica de metástasis en los ganglios linfáticos pélvicos laterales que se sometieron a una escisión mesorrectal total con disección de los ganglios linfáticos pélvicos laterales entre 2015 y 2020.PRINCIPALES MEDIDAS DE RESULTADO:Las indicaciones se establecieron utilizando los factores preoperatorios asociados con la metástasis de los ganglios linfáticos pélvicos laterales.RESULTADOS:Entre 105 pacientes, 36 (34,3%) tenían metástasis en los ganglios linfáticos pélvicos laterales confirmada patológicamente y 77 (73,3%) se sometieron a quimiorradiación preoperatoria. Los tumores ubicados dentro de los 5 cm desde el borde anal ( p = 0,02) y el tamaño inicial del ganglio ( p = 0,001) fueron predictores significativos de metástasis en los ganglios linfáticos pélvicos laterales. La sensibilidad fue del 100 % (36/36), con un punto de corte de 6 mm para el tamaño inicial del ganglio, seguido de 8 mm para el tamaño inicial del ganglio (94,4%, 34/36). Cuando se utilizó un tamaño de corte inicial del ganglio de 8 mm para una distancia entre el borde anal y el tumor >5 cm y 6 mm para una distancia entre el borde anal y el tumor ≤5 cm, la sensibilidad de la metástasis en los ganglios linfáticos pélvicos laterales fue del 100 %.LIMITACIONES:El diseño retrospectivo y el pequeño tamaño de la muestra.CONCLUSIONES:El tamaño inicial del ganglio y la altura del tumor fueron predictores significativos de metástasis en los ganglios linfáticos pélvicos laterales. Este estudio propuso que un tamaño de ganglio inicial de ≥8 mm con un tumor a >5 cm del margen anal y ≥6 mm con un tumor a ≤5 cm del margen anal son indicaciones óptimas para la disección de los ganglios linfáticos pélvicos laterales en el cáncer de recto. Consulte Video Resumen en http://links.lww.com/DCR/C101 . (Traducción-Dr. Yolanda Colorado ).

Management of lateral pelvic lymph nodes in rectal cancer

Lateral pelvic lymph node (LPLN) involvement occurs in 10%-25% of rectal cancer cases. Total mesorectal excision (TME) with routine LPLN dissection (LPLND) is predominantly applied in Japan whereas TME with neoadjuvant treatment are used in the West. LPLND is a morbid procedure and minimally invasive techniques may help reduce its morbidity. Selective lateral pelvic node dissection with TME following neoadjuvant treatment achieves acceptable disease-free and overall survival.

Robotic Lateral Pelvic Lymph Node Dissection Could Harvest More Lateral Pelvic Lymph Nodes over Laparoscopic Approach for Mid-to-Low Rectal Cancer: A Multi-Institutional Retrospective Cohort Study

Lateral pelvic lymph node dissection (LPND) is a technically demanding procedure. This study aimed to compare the short-term outcomes of laparoscopic and robotic LPNDs. This multi-institutional retrospective study included 108 consecutive patients who underwent laparoscopic or robotic total mesorectal excision with LPND for locally advanced rectal cancer. There were 74 patients in the laparoscopic and 34 in the robotic groups. The median operation time was longer in the robotic group than in the laparoscopic group (353 vs. 275 min, p < 0.001). No patients underwent conversion to open surgery in either group. Pathological LPN metastases were observed in 24 and 8 patients in the laparoscopic and robotic groups, respectively (p = 0.347). Although the number of harvested mesorectal lymph nodes was similar (15.5 vs. 15.0, p = 0.968), the number of harvested LPNs was higher in the robotic than in the laparoscopic group (7.0 vs. 5.0, p = 0.004). Postoperative complications and length of hospital stay were similar (robotic vs. laparoscopic, 35.3% and 7 days vs. 37.8% and 7 days, respectively). Both laparoscopic and robotic LPND are safe and feasible for locally advanced rectal cancers, but robotic LPND showed more harvested lateral lymph node than laparoscopic LPND.

Robotic versus laparoscopic approach for minimally invasive lateral pelvic lymph node dissection of advanced lower rectal cancer: a retrospective study comparing short-term outcomes

PURPOSE

The importance of lateral pelvic lymph node dissection (LLND) for advanced low rectal cancer is gradually being recognized in Europe and the USA, where some patients were affected by uncontrolled lateral pelvic lymph node (LLNs) metastasis, even after total mesorectal excision (TME) with neoadjuvant chemoradiotherapy (CRT). The purpose of this study was thus to compare robotic LLND (R-LLND) with laparoscopic (L-LLND) to clarify the safety and advantages of R-LLND.

METHODS

Sixty patients were included in this single-institution retrospective study between January 2013 and July 2022. We compared the short-term outcomes of 27 patients who underwent R-LLND and 33 patients who underwent L-LLND.

RESULTS

En bloc LLND was performed in significantly more patients in the R-LLND than in the L-LLND group (48.1% vs. 15.2%; p = 0.006). The numbers of LLNs on the distal side of the internal iliac region (LN 263D) harvested were significantly higher in the R-LLND than in the L-LLND group (2 [0-9] vs. 1 [0-6]; p = 0.023). The total operative time was significantly longer in the R-LLND than in the L-LLND group (587 [460-876] vs. 544 [398-859]; p = 0.003); however, the LLND time was not significantly different between groups (p = 0.718). Postoperative complications were not significantly different between the two groups.

CONCLUSION

The present study clarified the safety and technical feasibility of R-LLND with respect to L-LLND. Our findings suggest that the robotic approach offers a key advantage, allowing significantly more LLNs to be harvested from the distal side of the internal iliac region (LN 263D). Prospective clinical trials examining the oncological superiority of R-LLND are thus necessary in the near future.

Essential updates 2020/2021: Advancing precision medicine for comprehensive rectal cancer treatment

In the paradigm shift related to rectal cancer treatment, we have to understand a variety of new emerging topics to provide appropriate treatment for individual patients as precision medicine. However, information on surgery, genomic medicine, and pharmacotherapy is highly specialized and subdivided, creating a barrier to achieving thorough knowledge. In this review, we summarize the perspective for rectal cancer treatment and management from the current standard-of-care to the latest findings to help optimize treatment strategy.

Optimal diagnostic criteria for lateral lymph node dissection using magnetic resonance imaging: a multicenter prospective study

BACKGROUND

LLND in cases with suspected lateral lymph node (LLN) metastasis has been focused on as a novel treatment strategy in recent years. However, the optimal indication for LLND in rectal cancer patients has not been determined. This study aimed to establish the optimal indication for lateral lymph node dissection (LLND) in patients with rectal cancer using magnetic resonance imaging (MRI).

METHODS

A total of 209 patients with rectal adenocarcinoma who underwent total mesorectal excision and LLND in 13 hospitals were prospectively registered. By matching the sizes of the harvested LNs and those in magnetic resonance imaging (MRI), the pathological outcome of each LN was confirmed one-by-one. Using parameters of the LLNs in MRI, the optimal diagnostic criteria for LLND were established.

RESULTS

Of 3241 harvested LLNs, including 83 metastatic nodes, 1010 (31.1%) were visualized on MRI. Although all parameters assessed showed strong correlations with the presence of metastasis, none of these parameters could discriminate metastatic LLNs from non-metastatic nodes with sufficient sensitivity. However, by using the combination of long axis and short/long ratio in pretreatment MRI, we could establish optimal criteria for LLND. The sensitivity and specificity of the criteria for LLN metastasis were 94.3% and 40.2%, respectively.

CONCLUSIONS

In conclusion, we established novel criteria for LLND in rectal cancer patients using MRI. Our criteria will be of great clinical use in determining indications for LLND.

Case report: Indocyanine green fluorescence-guided imaging in laparoscope, a more sensitive detection technique of lateral lymph nodes metastases from rectal neuroendocrine tumors

Background

The diagnosis and surgical strategy of lateral lymph node metastases of rectal neuroendocrine tumors are still controversial. At present, the major diagnostic means rely on imaging examinations, but will be affected by the size of lymph nodes leading to false negativity. We provide a new technique to determine lateral lymph node metastases during surgery.

Clinical case

A 68-year-old man developed abdominal pain, bloating and fever for a month. Colonoscopy revealed the mass is 2.4 cm x 2.0 cm in size, with a wide stratum, poor mobility, and a rough but intact surface mucosa. Therefore, rectal neuroendocrine tumors (R-NET) were diagnosed. Multiple imaging methods, such as CT, octreotide imaging and endoscopic ultrasonography, have not found lateral lymph node metastases from rectal neuroendocrine tumors. But indocyanine green (ICG)-enhanced near-infrared fluorescence-guided imaging during surgery found left lateral lymph nodes metastases, which was proved by postoperative pathological examination.

Conclusions

We believe that applying ICG-enhanced near-infrared fluorescence-guided imaging in laparoscope can improve the detection of positive LLNs in those R-NET patients who did not reveal LNM on imaging examinations.

Clinical implication and management of rectal cancer with clinically suspicious lateral pelvic lymph node metastasis: A radiation oncologist's perspective

Rectal cancer is the eighth most common malignancy worldwide. With the introduction of total mesorectal excision (TME) and neoadjuvant chemoradiation (NCRT), intrapelvic local control has been remarkably improved. However, lateral pelvic recurrence remains problematic, especially in patients with clinically suspicious lateral pelvic lymph node (LPLN). LPLN dissection has been applied for the management of LPLN metastasis, mainly in Japan and other Eastern countries, while the role of NCRT is more emphasized and LPLN dissection is performed in very limited cases in Western countries. However, the optimal management strategy for patients with rectal cancer with suspicious LPLN metastasis has not been determined. Herein, we review the latest studies on the optimal management of LPLN metastasis to suggest the most appropriate treatment policies according to current evidence and discuss future research directions.

Japanese multicenter prospective study investigating laparoscopic surgery for locally advanced rectal cancer with evaluation of CRM and TME quality (PRODUCT trial)

Aim

In Japan, we have not been able to validate the results of laparoscopic surgery for locally advanced rectal cancer using the universal index "circumferential resection margin (CRM)." Previously, we established a semi-opened circular specimen processing method and validated its feasibility. In the PRODUCT trial, we aimed to assess CRM in patients with locally advanced rectal cancer who underwent laparoscopic rectal resection.

Methods

This was a multicenter, prospective, observational study. Eligible patients had histologically confirmed rectal adenocarcinoma located at or below 12 cm above the anal verge with clinical stage II or III and were scheduled for laparoscopic or robotic surgery. The primary endpoint was pathological CRM. CRM ≤1 mm was defined as positive.

Results

A total of 303 patients operated on between August 2018 and January 2020 were included in the primary analysis. The number of patients with clinical stage II and III was 139 and 164, respectively. Upfront surgery was performed for 213 patients and neoadjuvant therapy for 90 patients. The median CRM was 4.0 mm (IQR, 2.1-8.0 mm), and CRM was positive in 26 cases (8.6%). Univariate and multivariate analyses demonstrated that a predicted CRM from the mesorectal fascia of ≤1 mm on MRI was the significant factor for positive CRM (P = .0012 and P = .0045, respectively).

Conclusion

This study showed the quality of laparoscopic rectal resection based on the CRM in Japan. Preoperative MRI is recommended for locally advanced rectal cancer to prevent CRM positivity.

Magnetic Resonance Imaging Directed Surgical Decision Making for Lateral Pelvic Lymph Node Dissection in Rectal Cancer After Total Neoadjuvant Therapy (TNT)

OBJECTIVE

Lateral pelvic lymph node (LPLN) metastases are an important cause of preventable local failure in rectal cancer. The aim of this study was to evaluate clinical and oncological outcomes following magnetic resonance imaging (MRI)-directed surgical selection for lateral pelvic lymph node dissection (LPLND) after total neoadjuvant therapy (TNT).

METHODS

A retrospective consecutive cohort analysis was performed of rectal cancer patients with enlarged LPLN on pretreatment MRI. Patients were categorized as LPLND or non-LPLND. The main outcomes were lateral local recurrence rate, perioperative and oncological outcomes and factors associated with decision making for LPLND.

RESULTS

A total of 158 patients with enlarged pretreatment LPLN and treated with TNT were identified. Median follow-up was 20 months (interquartile range 10-32). After multidisciplinary review, 88 patients (56.0%) underwent LPLND. Mean age was 53 (SD±12) years, and 54 (34.2%) were female. Total operative time (509 vs 429 minutes; P =0.003) was greater in the LPLND group, but median blood loss ( P =0.70) or rates of major morbidity (19.3% vs 17.0%) did not differ. LPLNs were pathologically positive in 34.1%. The 3-year lateral local recurrence rates (3.4% vs 4.6%; P =0.85) did not differ between groups. Patients with LPLNs demonstrating pretreatment heterogeneity and irregular margin (odds ratio, 3.82; 95% confidence interval: 1.65-8.82) or with short-axis ≥5 mm post-TNT (odds ratio 2.69; 95% confidence interval: 1.19-6.08) were more likely to undergo LPLND.

CONCLUSIONS

For rectal cancer patients with evidence of LPLN metastasis, the appropriate selection of patients for LPLND can be facilitated by a multidisciplinary MRI-directed approach with no significant difference in perioperative or oncologic outcomes.

Identification of patient subgroups with low risk of postoperative local recurrence for whom total mesorectal excision surgery alone is sufficient: a multicenter retrospective analysis

PURPOSE

For rectal cancer, a multimodality approach is mandatory including neoadjuvant chemoradiotherapy, neoadjuvant chemotherapy, and lateral pelvic lymph node (LPLN) dissection, in addition to the total mesorectal excision (TME). However, these treatments are associated with adverse events. It is important to select patients who do or do not need these treatments.

METHODS

We retrospectively analyzed patients with cStage II and III rectal cancer who underwent curative resection at three hospitals. Recurrence patterns were classified into three types; pelvic cavity, LPLN, and distant recurrences, and the risk factors for each pattern of recurrence were compared. We then analyzed the risk of recurrence in the patients who underwent TME alone.

RESULTS

In total, 506 patients were enrolled in this study. Pelvic cavity recurrence was significantly associated with clinical assumption of circumferential resection margin involvement (cCRM) (p < 0.001), distant recurrence was associated with cN positivity (p < 0.001), and LPLN recurrence was associated with pretreatment LPLN swelling ≥ 5 mm (p < 0.001), lower tumor location (p = 0.016), and serum CEA level > 5 ng/mL (p = 0.008). In patients without cCRM and swollen LPLN, the local recurrence rate was extremely low even if they underwent TME alone; the 5-year recurrence rates of pelvic cavity and LPLN were 2.2% and 1.9%, respectively.

CONCLUSION

Additional treatments to TME for rectal cancer need to be performed based on the risk factors for each recurrence pattern.

Systematic review and meta-analysis of long-term oncological outcomes of lateral lymph node dissection for metastatic nodes after neoadjuvant chemoradiotherapy in rectal cancer

BACKGROUND

Standard Western management of rectal cancers with pre-treatment metastatic lateral lymph nodes (LLNs) is neoadjuvant (chemo)radiotherapy (nCRT) followed by total mesorectal excision (TME). In recent years, there is growing interest in performing an additional lateral lymph node dissection (LLND). The aim of this systematic review and meta-analysis was to investigate long-term oncological outcomes of nCRT followed by TME with or without LLND in patients with pre-treatment metastatic LLNs.

METHODS

PubMed, Ovid MEDLINE, Embase, Cochrane Library and Clinicaltrials.gov were searched to identify comparative studies reporting long-term oncological outcomes in pre-treatment metastatic LLNs of nCRT followed by TME and LLND (LLND+) vs. nCRT followed by TME only (LLND-). Newcastle-Ottawa risk-of-bias scale was used. Outcomes of interest included local recurrence (LR), disease-free survival (DFS), and overall survival (OS). Summary meta-analysis of aggregate outcomes was performed.

RESULTS

Seven studies, including 946 patients, were analysed. One (1/7) study was of good-quality after risk-of-bias analysis. Five-year LR rates after LLND+ were reduced (range 3-15%) compared to LLND- (11-27%; RR = 0.40, 95%CI [0.25-0.62], p < 0.0001). Five-year DFS was not significantly different after LLND+ (range 61-78% vs. 46-79% for LLND-; RR = 0.72, 95%CI [0.51-1.02], p = 0.143), and neither was five-year OS (range 69-91% vs. 72-80%; RR = 0.72, 95%CI [0.45-1.14], p = 0.163).

CONCLUSION

In rectal cancers with pre-treatment metastatic LLNs, nCRT followed by an additional LLND during TME reduces local recurrence risk, but does not impact disease-free or overall survival. Due to the low quality of current data, large prospective studies will be required to further determine the value of LLND.

Locally Recurrent Rectal Cancer According to a Standardized MRI Classification System: A Systematic Review of the Literature

(1) Background: The classification of locally recurrent rectal cancer (LRRC) is not currently standardized. The aim of this review was to evaluate pelvic LRRC according to the Beyond TME (BTME) classification system and to consider commonly associated primary tumour characteristics. (2) Methods: A systematic review of the literature prior to April 2020 was performed through electronic searches of the Science Citation Index Expanded, EMBASE, MEDLINE, and CENTRAL databases. The primary outcome was to assess the location and frequency of previously classified pelvic LRRC and translate this information into the BTME system. Secondary outcomes were assessing primary tumour characteristics. (3) Results: A total of 58 eligible studies classified 4558 sites of LRRC, most commonly found in the central compartment (18%), following anterior resection (44%), in patients with an 'advanced' primary tumour (63%) and following neoadjuvant radiotherapy (29%). Most patients also classified had a low rectal primary tumour. The lymph node status of the primary tumour leading to LRRC was comparable, with 52% node positive versus 48% node negative tumours. (4) Conclusions: This review evaluates the largest number of LRRCs to date using a single classification system. It has also highlighted the need for standardized reporting in order to optimise perioperative treatment planning.

Establishment and validation of a nomogram for predicting potential lateral pelvic lymph node metastasis in low rectal cancer

BACKGROUND

Identifying lateral pelvic lymph node (LPN) metastasis in low rectal cancer is crucial before treatment. Several risk factors and prediction models for LPN metastasis have been reported. However, there is no useful tool to accurately predict LPN metastasis. Therefore, we aimed to construct a nomogram for predicting LPN metastasis in rectal cancer.

METHODS

We analyzed the risk factors for potential LPN metastasis by logistic regression analysis in 705 patients who underwent primary resection of low rectal cancer. We included patients at 49 institutes of the Japan Society of Laparoscopic Colorectal Surgery between June 2010 and February 2012. Clinicopathological factors and magnetic resonance imaging findings were evaluated. The nomogram performance was assessed using the c-index and calibration plots, and the nomogram was validated using an external cohort.

RESULTS

In the univariable logistic regression analysis, age, sex, carcinoembryonic antigen, tumor location, clinical T stage, tumor size, circumferential resection margin (CRM), extramural vascular invasion (EMVI), and the short and long axes of LPN and perirectal lymph node (PRLN) were nominated as risk factors for potential LPN metastasis. We identified a combination of the short axis of LPN, tumor location, EMVI, and short axis of PRLN as optimal for predicting potential LPN metastasis and developed a nomogram using these factors. This model had a c-index of 0.74 and was moderately calibrated and well-validated.

CONCLUSIONS

This is the first study to construct a well-validated nomogram for predicting potential LPN metastasis in rectal cancer, and its performance was high.

The Role of Simultaneous Integrated Boost in Locally Advanced Rectal Cancer Patients with Positive Lateral Pelvic Lymph Nodes

Aims: Between 11 to 14% of patients with locally advanced rectal cancer (LARC) have positive lateral pelvic lymph nodes (LPLN) at diagnosis, related to a worse prognosis with a 5-year survival rate between 30 to 40%. The best treatment choice for this group of patients is still a challenge. The optimal radiotherapy (RT) dose for LPLN patients has been investigated. Methods: We retrospectively collected data from LARC patients with LPLN at the primary staging MRI, treated in our center from March 2003 to December 2020. Patients underwent a neoadjuvant concomitant chemo-radiotherapy (CRT) treatment on the primary tumor (T), mesorectum, and pelvic nodes, associated with a fluoride-based chemotherapy. The total reached dose was 45 Gy at 1.8 Gy/fr on the elective sites and 55 Gy at 2.2 Gy/fr on the disease and mesorectum. Patients were divided in two groups based on whether they received a simultaneous integrated RT boost on the LPLN or not. Overall Survival (OS), Disease Free Survival (DFS), Metastasis Free Survival (MFS), and Local Control (LC) were evaluated in the whole group and then compared between the two groups. Results: A total of 176 patients were evaluated: 82 were included in the RT boost group and 94 in the non-RT boost group. The median follow-up period was 57.8 months. All the clinical endpoint (OS, DFS, MFS, LC), resulted were affected by the simultaneous integrated boost on LPLN with a survival rate of 84.7%, 79.5%, 84.1%, and 92%, respectively, in the entire population. From the comparison of the two groups, there was a statistical significance towards the RT boost group with a p < 0.006, 0.030, 0.042, 0.026, respectively. Conclusions: Concomitant radiotherapy boost on positive LPLN has shown to be beneficial on the survival outcomes (OS, DFS, MFR, and LC) in patients with LARC and LPLN. This analysis demonstrates that a higher dose of radiotherapy on positive pelvic lymph nodes led not only to a higher local control but also to a better survival rate. These results, if validated by future prospective studies, can bring a valid alternative to the surgery dissection without the important side effects and permanent disabilities observed during the years.

Functional outcomes after lateral pelvic lymph node dissection for rectal cancer: a systematic review and meta-analysis

PURPOSE

Lateral pelvic lymph node dissection (LPLND) may improve oncological outcomes for select patients with rectal cancer, though functional outcomes may be adversely impacted. The aim of this study is to assess the functional outcomes associated with LPLND for rectal cancer and compare these outcomes with standard surgical resection.

METHODS

A systematic search was undertaken to identify relevant studies reporting on urinary dysfunction (UD), sexual dysfunction (SD), and defecatory dysfunction (DD) for patients who underwent LPLND for rectal cancer. Studies comparing functional outcomes in patients who underwent surgery with and without LPLND were assessed. In addition, a comparison of functional outcomes in patients who underwent LPLND before and after the year 2000 was performed.

RESULTS

Twenty-one studies of predominantly non-randomised observational data were included. Ten were comparative studies. Male SD was worse in patients who underwent LPLND compared with those who did not (RR 1.68 (95% CI 1.41-1.99, P < 0.001)). No difference was observed for the rate of UD between treatment groups. The rates of UD and male SD in patients who underwent LPLND after the year 2000 were significantly lower than those who underwent LPLND before the year 2000 ((UD) RR = 4.5, p value = 0.0034; male SD RR = 28.7, p value < 0.001).

CONCLUSION

Lateral pelvic lymph node dissection is associated with worse male sexual dysfunction compared to standard surgical resection. However, the rates of urine dysfunction and male sexual dysfunction are better in contemporary cohorts which may reflect improved surgical technique and autonomic nerve preservation.

Combination of extramural venous invasion and lateral lymph node size detected with magnetic resonance imaging is a reliable biomarker for lateral lymph node metastasis in patients with rectal cancer

PURPOSE

Pathological extramural venous invasion (EMVI) is defined as the active invasion of malignant cells into veins beyond the muscularis propria in colorectal cancer. It is associated with poor prognosis and increases the risk of disease recurrence. Specific findings on MRI (termed MRI-EMVI) are reportedly associated with pathological EMVI. In this study, we aimed to identify risk factors for lateral lymph node (LLN) metastasis related to rectal cancer and to evaluate whether MRI-EMVI could be a new and useful imaging biomarker to help LLN metastasis diagnosis besides LLN size.

METHODS

We investigated 67 patients who underwent rectal resection and LLN dissection for rectal cancer. We evaluated MRI-EMVI grading score and examined the relationship between MRI-EMVI and LLN metastasis.

RESULTS

Pathological LLN metastasis was detected in 18 cases (26.9%), and MRI-EMVI was observed in 32 cases (47.8%). Patients were divided into two cohorts, according to LLN metastasis. Multivariate analyses demonstrated that higher risk of LLN metastasis was significantly associated with MRI-EMVI (P = 0.0112) and a short lateral lymph node axis (≥ 5 mm) (P = 0.0002). The positive likelihood ratios of MRI-EMVI alone, LLN size alone, and the combination of both factors were 2.12, 4.84, and 16.33, respectively. Patients negative for both showed better 2-year relapse-free survival compared to other patients (84.4% vs. 62.1%, P = 0.0374).

CONCLUSIONS

MRI-EMVI was a useful imaging biomarker for identifying LLN metastasis in patients with rectal cancer. The combination of MRI-EMVI and LLN size can improve diagnostic accuracy.

The survival impact of preoperative FOLFOX for resectable locally advanced rectal cancer: the R-NAC-01 study

PURPOSE

In this follow-up of the R-NAC-01 study, we assessed the long-term oncological benefit of four courses of modified leucovorin, 5-fluorouracil (FU), and oxaliplatin (mFOLFOX6) chemotherapy before rectal surgery.

METHODS

In this prospective, multicenter study (UMIN 000012559) involving 11 hospitals in Japan, patients with lower rectal cancer underwent four cycles of mFOLFOX6 chemotherapy and subsequent surgery within four to six weeks. The 3-year recurrence-free survival and local recurrence rates were then reported.

RESULTS

Of 41 patients (36 males, 5 females; mean age: 60.8 years old) who received 4 courses of chemotherapy, 40 underwent total mesorectal excision, and 1 underwent total pelvic exenteration. R0 resection was achieved in 40 patients, but none showed a pathological complete response. Twenty-nine patients received adjuvant chemotherapy for an average of 4 months. The 3 year recurrence-free survival and local recurrence rates in patients undergoing curable resection were 72.8% and 8.5%, respectively. cStage III patients with adjuvant chemotherapy had a significantly higher 3 year recurrence-free survival than those without adjuvant chemotherapy (76.6 vs. 40.0%, log-rank p = 0.03).

CONCLUSION

Four courses of mFOLFOX6 chemotherapy before surgery may be a promising treatment strategy for locally advanced rectal cancer. Adjuvant chemotherapy might be needed for cStage III patients, even after four courses of neoadjuvant mFOLFOX6.

Lateral Pelvic Lymph Node Dissection After Neoadjuvant Chemoradiotherapy in Patients With Rectal Cancer: A Single-Center Experience and Literature Review

Purpose

We aimed to evaluate the surgicopathological outcomes of lateral pelvic lymph node dissection (LPLD) and long-term oncological outcomes of selective LPLD after neoadjuvant chemoradiotherapy (nCRT) in patients with locally advanced rectal cancer and compare them to those of total mesorectal excision (TME) alone based on pretreatment magnetic resonance imaging (MRI).

Methods

We compared the TME-alone group (2001–2009, n=102) with the TME with LPLD group (2011–2016, n=69), both groups having lateral lymph nodes (LLNs) of ≥5 mm in short axis diameter. The surgicopathological outcomes were analyzed retrospectively. Oncological outcomes were analyzed using the Kaplan-Meier method.

Results

The rates of overall postoperative 30-day morbidity (42.0% vs. 26.5%, P=0.095) and urinary retention (13.7% vs. 10.1%, P=0.484) were not significantly different between the LPLD and TME-alone groups, respectively. Pathologically proven LLN metastasis was identified in 24 (34.8%) LPLD cases after nCRT. The LPLD group showed a lower 5-year local recurrence (LR) rate (27.9% vs. 4.6%, P<0.001) and better recurrence-free survival (RFS) (59.6% vs. 78.2%, P=0.008) than those of the TME-alone group, while the 5-year overall survival was not significantly different between the 2 groups (76.2% vs. 86.5%, P=0.094).

Conclusion

This study suggests that LPLD is a safe and feasible procedure. The oncological outcomes suggest that selective LPLD improves LR and RFS in patients with clinically suspicious LLNs on pretreatment MRI. Considering that lateral nodal disease is not common, a multicenter large-scale study is necessary.

Current practices concerning the assessment and treatment of lateral lymph nodes in low rectal cancer: a survey among colorectal surgeons in The Netherlands

PURPOSE

The presence of lateral lymph nodes (LLNs) in patients with rectal cancer is not always acknowledged by the multidisciplinary team or treated in a standardized manner, and (inter)national guidelines concerning this topic are lacking. This study aimed to evaluate current practices regarding the assessment and treatment of LLNs in rectal cancer patients based on a survey among Dutch colorectal surgeons.

METHODS

An online survey was sent to members of the Dutch Association of Coloproctology. The survey consisted of 16 questions addressing their views on diagnosis, restaging, and treatment approaches for suspicious LLNs.

RESULTS

A total of 62 surgeons from 50 Dutch hospitals responded. For patients with a distal cT3/T4 rectal tumor; lateral lymph node compartments were routinely discussed during multidisciplinary meetings in only nine hospitals (18%). When defining what makes an LLN suspicious; the size threshold varied from >3 to >10 mm (median 7, SD 2), and MRI-based malignant features were mentioned by 29 surgeons (47%). Surgeons stated eight different treatment strategies as their designated treatment of suspicious LLNs. A total of 33 surgeons (53%) would add a radiotherapy boost to the neoadjuvant treatment. In cases of surgical resection; 12 surgeons (19%) would remove the suspicious LLN by 'node-picking' and 44 surgeons (71%) would perform a lateral lymph node dissection. The variation was not influenced by hospital type or surgeon's experience.

CONCLUSION

These results highlight the vast variation in the awareness, definition of suspicious LLNs in rectal cancer, and different treatment approaches. International guidelines based on further research are warranted.

Radiologic Factors and Areas of Local Recurrence in Locally Advanced Lower Rectal Cancer After Lateral Pelvic Lymph Node Dissection

BACKGROUND

Identifying preoperative risk factors of local recurrence and patterns of treatment failure resulting after rectal cancer management is important for planning treatment strategies and improving the results of multidisciplinary care.

OBJECTIVE

The purpose of this study was to analyze the associations between the preoperative factors and local recurrence and to investigate the local recurrence areas in patients with locally advanced lower rectal cancer who underwent lateral pelvic lymph node dissection.

DESIGN

The study used a retrospective cohort design.

SETTINGS

It was conducted at a single institution.

PATIENTS

Overall 469 patients with locally advanced lower rectal adenocarcinoma located below the peritoneal reflex who received curative resection with lateral pelvic lymph node dissection during 2010 to 2018 were included.

MAIN OUTCOME MEASURES

Independent risk factors for local recurrence were assessed using multivariate Cox regression. Local recurrence was classified into 3 areas using follow-up images.

RESULTS

A total of 286 patients underwent upfront surgery, 132 patients received neoadjuvant chemotherapy followed by surgery, and 51 patients received preoperative chemoradiotherapy followed by surgery. Eighty-six patients (18.3%) were extramural venous invasion positive, and 113 patients (24.1%) were circumferential resection margin positive. The median follow-up period was 46 months. Local recurrence showed significant association with extramural venous invasion positive (HR = 2.596 (95% CI, 1.321-5.102); p = 0.006) or circumferential resection margin positive (HR = 2.298 (95% CI, 1.158-4.560); p = 0.017). The incidence of local recurrence was observed in 51 patients (10.8%), with the pelvic plexus and internal iliac area being the most frequent (6.6%), followed by the central pelvis area (3.8%), and was markedly low in the obturator area (0.4%).

LIMITATIONS

This was a retrospective, single-institution design.

CONCLUSIONS

Extramural venous invasion status and circumferential resection margin status were associated with a high local recurrence rate in patients who underwent lateral pelvic lymph node dissection. In addition, local recurrence in the obturator area was low compared with that in other areas. See Video Abstract at http://links.lww.com/DCR/B683.

FACTORES RADIOLGICOS Y REAS DE RECURRENCIA LOCAL EN EL CNCER DE RECTO INFERIOR LOCALMENTE AVANZADO DESPUS DE LA DISECCIN GANGLIONAR PLVICA LATERAL

ANTECEDENTES:El identificar los factores de riesgo preoperatorios para recurrencia local y los patrones de fracaso del tratamiento que resultan del manejo del cáncer de recto es importante para planificar las estrategias de tratamiento y mejorar los resultados de la atención multidisciplinaria.OBJETIVO:Analizar las asociaciones entre los factores preoperatorios y la recidiva local, e investigar las áreas de recidiva local en pacientes con cáncer de recto inferior localmente avanzado que se sometieron a disección de ganglios linfáticos pélvicos laterales.DISEÑO:Un diseño de cohorte retrospectivo.ENTORNO CLÍNICO:Una sola institución.PACIENTES:Un total de 469 pacientes con adenocarcinoma rectal inferior localmente avanzado ubicado debajo del reflejo peritoneal que recibieron resección curativa con disección de ganglios linfáticos pélvicos laterales durante 2010-2018.PRINCIPALES MEDIDAS DE RESULTADO:Los factores de riesgo independientes de recurrencia local se evaluaron mediante regresión de Cox multivariante. La recurrencia local se clasificó en 3 áreas utilizando imágenes de seguimiento.RESULTADOS:Doscientos ochenta y seis pacientes se sometieron a cirugía inicial, 132 pacientes recibieron quimioterapia neoadyuvante seguida de cirugía y 51 pacientes recibieron quimiorradioterapia preoperatoria seguida de cirugía. Ochenta y seis pacientes (18,3%) fueron positivos para invasión venosa extramural y 113 pacientes (24,1%) fueron positivos para el margen de resección circunferencial. La mediana del período de seguimiento fue de 46 meses. La recidiva local mostró una asociación significativa con la invasión venosa extramural positiva (cociente de riesgo: 2,596; intervalo de confianza del 95%: 1,321-5,102; p = 0,006) o el margen de resección circunferencial positivo (cociente de riesgo: 2,298; intervalo de confianza del 95%: 1,158-4,560; p = 0,017). La incidencia de recidiva local se observó en 51 pacientes (10,8%), siendo el plexo pélvico y el área ilíaca interna los más frecuentes (6,6%), seguidos del área pélvica central (3,8%), y fue marcadamente baja en el área del obtudador (0.4%).LIMITACIONES:Un diseño retrospectivo de una sola institución.CONCLUSIONES:El estado de invasión venosa extramural o el estado del margen de resección circunferencial se asociaron con una alta tasa de recurrencia local en pacientes que se sometieron a disección de ganglios linfáticos pélvicos laterales. Además, la recurrencia local en el área del obturador fue baja en comparación con la de otras áreas. Consulte Video Resumen en http://links.lww.com/DCR/B683.

Impact of the distal resection margin on local recurrence after neoadjuvant chemoradiation and rectal excision for locally advanced rectal cancer

We aimed to evaluate whether a short distal resection margin (< 1 cm) was associated with local recurrence in patients with locally advanced rectal cancer who underwent preoperative chemoradiotherapy. Patients with rectal cancer who underwent preoperative chemoradiotherapy followed by curative surgery were divided into two groups based on the distal resection margin (≥ 1 cm and < 1 cm). In total, 507 patients were analyzed. The median follow-up duration was 48.9 months. The 3-year local recurrence rates were 2% and 8% in the ≥ 1 cm and < 1 cm groups, respectively (P < 0.001). Multivariable analysis revealed that a distal resection margin of < 1 cm was a significant risk factor for local recurrence (P = 0.008). Subgroup analysis revealed that a distal resection margin of < 1 cm was not an independent risk factor for local recurrence in the ypT0-1 group. However, among patients with tumor stages ypT2-4, the cumulative 3-year incidences of local recurrence were 2.3% and 9.8% in the ≥ 1 cm and < 1 cm groups, respectively (P = 0.01). A distal resection margin of < 1 cm might influence local recurrence rates in patients with locally advanced rectal cancer undergoing preoperative chemoradiotherapy, especially in patients with tumor stages ypT2-4.

Lateral lymph node dissection in rectal cancer: State of the art review

Half of the local regional recurrences from rectal cancer are nowadays located in the lateral compartments, most likely due to lateral lymph node (LLN) metastases. There is evidence that a lateral lymph node dissection (LLND) can lower the lateral local recurrence rate. An LLND without neoadjuvant (chemo)radiotherapy in patients with or without suspected LLN metastases has been the standard of care in the East, while Western surgeons believed LLN metastases to be cured by neoadjuvant treatment and total mesorectal excision (TME) only. An LLND in patients without enlarged LLNs might result in overtreatment with low rates of pathological LLNs, but in patients with enlarged LLNs who are treated with (C)RT and TME only, the risk of a lateral local recurrence significantly increases to 20%. Certain Eastern and Western centers are increasingly performing a selective LLND after neoadjuvant treatment in the presence of suspicious LLNs due to new scientific insights, but (inter)national consensus on the indication and surgical approach of LLND is lacking. An LLND is an anatomically challenging procedure with intraoperative risks such as bleeding and postoperative morbidity. It is therefore essential to carefully select the patients who will benefit from this procedure and where possible to perform the LLND in a minimally invasive manner to limit these risks. This review gives an overview of the current evidence of the assessment of LLNs, the indications for LLND, the surgical technique, pitfalls in performing this procedure and the future studies are discussed, aiming to contribute to more (inter)national consensus.

Rise and fall of total mesorectal excision with lateral pelvic lymphadenectomy for rectal cancer: an updated systematic review and meta-analysis of 11,366 patients

The role of lateral lymph node dissection (LLND) during total mesorectal excision (TME) for rectal cancer is still controversial. Many reviews were published on prophylactic LLND in rectal cancer surgery, some biased by heterogeneity of overall associated treatments. The aim of this systematic review and meta-analysis is to perform a timeline analysis of different treatments associated to prophylactic LLND vs no-LLND during TME for rectal cancer.

METHODS

A literature search was performed in PubMed, SCOPUS and WOS for publications up to 1 September 2020. We considered RCTs and CCTs comparing oncologic and functional outcomes of TME with or without LLND in patients with rectal cancer.

RESULTS

Thirty-four included articles and 29 studies enrolled 11,606 patients. No difference in 5-year local recurrence (in every subgroup analysis including preoperative neoadjuvant chemoradiotherapy), 5-year distant and overall recurrence, 5-year overall survival and 5-year disease-free survival was found between LLND group and non LLND group. The analysis of post-operative functional outcomes reported hindered quality of life (urinary, evacuatory and sexual dysfunction) in LLND patients when compared to non LLND.

CONCLUSION

Our publication does not demonstrate that TME with LLND has any oncological advantage when compared to TME alone, showing that with the advent of neoadjuvant therapy, the advantage of LLND is lost. In this review, the most important bias is the heterogeneous characteristics of patients, cancer staging, different neoadjuvant therapy, different radiotherapy techniques and fractionation used in different studies. Higher rate of functional post-operative complications does not support routinely use of LLND.

The Addition of Preoperative Radiation Is Insufficient for Lateral Pelvic Control in a Subgroup of Patients With Low Locally Advanced Rectal Cancer: A Post Hoc Study of a Randomized Controlled Trial

BACKGROUND

The local recurrence of rectal cancer has been improved by total mesorectal excision following neoadjuvant chemoradiotherapy. However, in patients with low locally advanced rectal cancer, lateral pelvic recurrence remains to be addressed.

OBJECTIVE

This study aimed to determine the efficiency of neoadjuvant radiotherapy in addressing lateral pelvic recurrence and which subgroup of patients might be optimal to receive lateral lymph node dissection.

DESIGN

The MRI/CT images were reassessed for lateral lymph node status. The lateral lymph nodes with short axis ≥5 mm and ≥4 mm were considered positive in pretreatment and restaging MRI/CT.

SETTING

This was a post hoc analysis of a prospective randomized controlled trial (FOWARC, NCT01211210).

PATIENTS

A total of 495 patients with stage II or III rectal adenocarcinoma were included in the original trial. According to the excluding criteria, the finally included population consists of 253 patients; of these, 195 patients received neoadjuvant chemoradiotherapy and 94 received chemotherapy alone.

MAIN OUTCOMES AND MEASURES

The primary outcome was the 5-year lateral pelvic recurrence rate.

RESULTS

Compared with patients receiving chemotherapy alone, patients receiving additional radiotherapy had a marginal significance of lower lateral pelvic recurrence rate (6.6% vs 13.0%; p = 0.051). In the subset with pretreatment positive lateral lymph nodes, patients had a lateral pelvic recurrence rate of 22.6% and 45.1% after neoadjuvant chemoradiotherapy and chemotherapy alone. Of note, 34.9% of the pretreatment positive lateral lymph nodes were persistent after neoadjuvant chemoradiotherapy, culminating in a lateral pelvic recurrence rate of 63.3%.

LIMITATIONS

This is a post hoc analysis, and only the patients from the leading center were included, which limited the sample size. In addition, the lateral lymph node dissection was not performed in this cohort.

CONCLUSIONS

The addition of radiotherapy in neoadjuvant regimens could not address lateral pelvic recurrence adequately. Some subgroups of patients might need additional dissection. See Video Abstract at http://links.lww.com/DCR/B613.

LA INCLUSION DE LA RADIOTERAPIA PREOPERATORIA ES INSUFICIIENTE EN EL CONTROL PLVICO LATERAL EN UN SUBGRUPO DE PACIENTES CON CNCER DE RECTO INFERIOR LOCALMENTE AVANZADO UN ESTUDIO POSTHOC CONTROLADO Y RANDOMIZADO

ANTECEDENTES:La recurrencia local del cancer de recto ha disminuido al efectuar una excision mesorrectal total seguida de quimioradioterapia neoadyuvante. No obstante, en pacientes con cancer de tercio inferior de recto avanzado localmente, aún está por controlarse la recurrencia pélvicaOBJETIVOS:Determinar la eficacia de la radioterapia neoadyuvante en el control de la recurrencia pélvica lateral y en que subgrupo de pacientes sería conveniente efecutar una excisión lateral de las cadenas ganglionares.DISEÑO:Se reevaluaron las imágenes tomográficas y de resonancia magnética del status de las cadenas ganglionares linfáticas laterales. Los ganglios linfáticos laterales con un eje-corto > 5 mm y ≥ 4 mm se consideraron como positivos previo al tratamiento y reestadificados con RM y TAC respectivamente.ESCENARIO:Es un análisis post hoc de un studio prospectivo randomizado controlado (FOWARC, NCT01211210).PACIENTESSe incluyeron un total de 495 pacientes en estdio II o III con adenomcarcinoma rectal en el estudio original. De acuerdo a los criterios de exclusión, la población final incluida consistió en 253 pacientes; de estos, 195 recibieron quimioradioterapia neoadyuvante y 94 quimioterapia sola.EVALUACION DE LOS RESULTADOS PRINCIPALES:El parámetro mas importante fue la tasa de recurrencia pélvica lateral a cinco años.RESULTADOS:En comparación con los pacientes que recibieron quimioterapia sola, aquellos que además fueron sometidos a radioterapia adicional presentaron un margen significativo de menor tasa de recurrencia pélvica lateral (6.6% vs. 13.0%; p=0.051). En el grupo de pacientes con ganglios linfáticos laterales positivos, los enfermos presentaron una tasa de recurrencia pélvica lateral de 22.6% y 45.1% después de quimioradiaterapia neoadyuvante en comparación con quimioterapia sola respectivamente. Cabe mencionar que el 34.9% de los pacientes con ganglios linfáticos laterales positivos antes del tratamiento persistieron después de la quimioradioterapia neoadyuvante, reportándose finalmente una recurrencia pélvica lateral de un 63.3%.LIMITACIONES:Se trata de un análisis posthoc y solo los pacientes del hospital fueron incluidos, lo que limita el tamaño de la muestra. Además, no se efectuó la disección de los ganglios linfáticos laterales en este grupo.CONCLUSIONES:La radioterapia en los esquemas de neoadyuvancia no logran controlar la recurrencia pélvica lateral en forma adecuada. Algunos subgrupos de pacientes podría requerir de disección adicional. Consulte Video Resumen en http://links.lww.com/DCR/B613.

From "East vs West" towards international multidisciplinary collaboration: An appraisal of lateral lymph nodes in rectal cancer

Western and Eastern practices have traditionally differed in their approach to treating lateral lymph nodes in rectal cancer. While Western clinicians have primarily favored neoadjuvant (chemo)radiotherapy to sterilize lateral compartments, Eastern physicians have often opted for the surgical removed of lymphatic tissue with a lateral lymph node dissection without neoadjuvant treatment. The literature suggests similar oncological outcomes for these two separate techniques, while tangible differences exist. The combination of these paradigms may be beneficial in reducing overall morbidity while sustaining low recurrence rates. This article considers traditional Eastern and Western perspectives, discusses nodal features important for predicting malignancy and attempts to stimulate international, multidisciplinary consensus and collaboration.

Lateral lymph node dissection in advanced low rectal cancer treatment

Lateral lymph node (LLN) metastasis is a determinant of local recurrence in advanced low rectal cancer. Lateral lymph node dissection (LLND) is effective in removing metastatic lymph nodes, and has been shown to have a decreased local recurrence rate. However, because of its complexity and complications it induces, there is still tremendous controversy about its usage. Neoadjuvant chemoradiotherapy (nCRT) and total mesorectal excision (TME) are recommended as a conventional treatment for advanced rectal cancer. However, LLN metastasis and local recurrence still occur despite nCRT with TME. In Japan, TME with LLND is the standard surgical treatment for Stage II/III of advanced low rectal cancer. Before surgery, a proper evaluation of LLN status should be performed. Laparoscopic LLND and robotic-assisted LLND are useful for this. More research is necessary to improve the oncological outcomes of LLND. In this review, we retrospectively examine previous reports about LLND, aiming to emphasize its application prospects to improve patient survival and life quality.