Optimal treatment strategies for clinically suspicious lateral pelvic lymph node metastasis in rectal cancer

Long-term Complications of Laparoscopic or Robotic Lateral Pelvic Node Dissection After Preoperative Chemoradiotherapy for Locally Advanced Rectal Cancer

BACKGROUND

Patients with rectal cancer who underwent lateral pelvic node dissection might be at a higher risk of postoperative complications derived from technical complexity. However, little is known regarding the long-term complications after lateral pelvic node dissection.

OBJECTIVES

The study aimed to investigate the long-term complications of preoperative chemoradiotherapy, followed by total mesorectal excision with lateral pelvic node dissection for locally advanced rectal cancers.

DESIGN

A retrospective analysis of a prospectively collected database.

SETTINGS

This study was conducted in a tertiary cancer center.

PATIENTS

Patients with rectal cancer who underwent total mesorectal excision with lateral pelvic node dissection after preoperative chemoradiotherapy between 2011 and 2019 were analyzed. All operations were performed via a laparoscopic or robotic approach.

MAIN OUTCOME MEASURES

Long-term complications were defined as adverse events that persisted or newly appeared ≥90 days after surgery and could be related to the surgery.

RESULTS

A total of 164 patients underwent total mesorectal excision with lateral pelvic node dissection after preoperative chemoradiotherapy. Short-term and long-term complication rates were 36.0% and 36.6%, respectively. Lymphocele was the most common long-term complication (17.7% of patients), and 11.6% had anastomotic leakage with chronic sinus. Of the patients with long-term complications, 20.7% of patients needed readmission for treatment. Of the 29 patients with lymphocele, 13 (41.0%) experienced spontaneous absorption and 11 (37.9%) required surgical or percutaneous catheter drainage or antibiotics use. Multivariate analysis showed pathologic pelvic node metastases ( p = 0.008), and a higher number of unilateral harvested pelvic nodes ( p = 0.001) were significantly associated with long-term complications. At the last follow-up (median duration of 43 months), 15.9% of patients had unresolved complications.

LIMITATIONS

The retrospective design.

CONCLUSIONS

Patients undergoing lateral pelvic node dissection experienced a higher frequency of long-term complications, but half of them had asymptomatic lymphoceles, most of which resolved spontaneously. However, further efforts should be paid to reduce anticipated complications related to lateral pelvic node dissection. See Video Abstract .

COMPLICACIONES A LARGO PLAZO DE LA DISECCIN DE LOS GANGLIOS LIFTICOS PLVICOS LATERALES LAPAROSCPICA O ROBTICA DESPUS DE LA QUIMIORRADIOTERAPIA PREOPERATORIA CONTRA EL CNCER DEL RECTO LOCALMENTE AVANZADO

ANTECEDENTES:Los pacientes con cáncer del recto sometidos a disección ganglionar linfática pélvica lateral podrían tener mayor riesgo de complicaciones postoperatorias derivadas de la complejidad técnica. Sin embargo, se sabe poco sobre las complicaciones a largo plazo después de la disección de los ganglios linfáticos pélvicos laterales.OBJETIVOS:Investigar las complicaciones a largo plazo de la quimiorradioterapia preoperatoria, seguida de escisión mesorrectal total con disección de los ganglios linfáticos pélvicos laterales contra el cáncer de recto localmente avanzado.DISEÑO:Un análisis retrospectivo de una base de datos recopilada prospectivamente.AJUSTES:Este estudio se llevó a cabo en un centro oncológico terciario.PACIENTES:Se analizaron pacientes con cáncer de recto que se sometieron a escisión mesorrectal total con disección de ganglios linfáticos pélvicos laterales después de quimiorradioterapia preoperatoria entre 2011 y 2019. Todas las operaciones se realizaron mediante abordaje laparoscópico o robótico.PRINCIPALES MEDIDAS DE RESULTADO:Las complicaciones a largo plazo se definieron como eventos adversos que persistieron o aparecieron recientemente ≥ 90 días después de la cirugía y podrían estar relacionados con la cirugía.RESULTADOS:Un total de 164 pacientes se sometieron a escisión mesorrectal total con disección de los ganglios linfáticos pélvicos laterales después de quimiorradioterapia preoperatoria. Las tasas de complicaciones a corto y largo plazo fueron del 36,0% y 36,6%, respectivamente. El linfocele fue la complicación a largo plazo más común (17,7% de los pacientes) y el 11,6% tuvo fuga anastomótica con seno crónico. De los pacientes con complicaciones a largo plazo, el 20,7% de los pacientes necesitaron reingreso para recibir tratamiento. De 29 pacientes con linfocele, 13 (41,0%) experimentaron absorción espontánea y 11 (37,9%) requirieron drenaje quirúrgico o percutáneo con catéter o uso de antibióticos. El análisis multivariado mostró metástasis patológicas en los ganglios linfáticos pélvicos ( p = 0,008) y un mayor número de ganglios pélvicos extraídos unilateralmente ( p = 0,001) se asociaron significativamente con complicaciones a largo plazo. En el último seguimiento (mediana de 43 meses), el 15,9% de los pacientes tuvieron complicaciones no resueltas.LIMITACIÓN:El diseño retrospectivo.CONCLUSIONES:Los pacientes sometidos a disección de ganglios pélvicos linfáticos laterales experimentaron una mayor frecuencia de complicaciones a largo plazo, pero la mitad de ellos tuvieron linfoceles asintomáticos, la mayoría de los cuales se resolvieron espontáneamente. Sin embargo, se deben realizar mayores esfuerzos para reducir las complicaciones previstas relacionadas con la disección de los ganglios linfáticos pélvicos laterales. (Traducción-Dr. Aurian Garcia Gonzalez ).

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.

Sequential Lateral Lymphatic Metastasis Shows Similar Oncologic Outcomes to Upward Spread in Advanced Rectal Cancer After Preoperative Chemoradiotherapy

BACKGROUND

Whether lateral pelvic node metastasis should be considered as a regional or systemic disease is a long-standing debate. Although previous Japanese studies have considered it to be locoregional disease, Western countries consider it a systemic disease and do not perform lateral pelvic node dissection after preoperative chemoradiotherapy.

OBJECTIVE

To evaluate whether lateral pelvic node metastasis is a systemic or regional disease that is amenable to curative resection.

DESIGN

Retrospective analysis of a prospectively collected database.

SETTING

This study was conducted at a tertiary cancer center.

PATIENTS

There were 616 consecutive patients who underwent curative total mesorectal excision alone or with lateral pelvic node dissection after preoperative chemoradiotherapy for locally advanced rectal cancer between 2011 and 2019.

MAIN OUTCOME MEASURES

Three-year disease-free and overall survival.

RESULTS

A total of 360 patients underwent total mesorectal excision, and 160 patients underwent total mesorectal excision with lateral pelvic node dissection. There was no difference in the 3-year disease-free survival (DFS; p = 0.844) or overall survival rates ( p = 0.921) between the groups. Patients with lateral pelvic node metastasis showed DFS similar to those with perirectal lymph node metastasis in the total mesorectal excision group. In a subgroup analysis, patients with internal iliac pelvic node metastasis showed a disease-free survival comparable to those with perirectal node involvement, and patients with other lateral pelvic node metastasis showed a DFS similar to those with intermediate node involvement. In the lateral pelvic node dissection group, the lateral pelvic node metastatic rate was 32.5%. On multivariate analysis, fewer than 8 of the unilateral harvested lateral pelvic nodes and advanced ypT stage were significantly associated with poor disease-free survival.

LIMITATION

The retrospective design.

CONCLUSIONS

Lateral lymphatic metastasis showed oncologic outcomes similar to those of upward spread, especially perirectal lymph nodes metastasis. Large cohort studies with long-term follow-up are required to confirm these results. See Video Abstract .

LAS METSTASIS LINFTICAS SECUENCIALES LATERALES MUESTRAN RESULTADOS ONCOLGICOS SIMILARES EN LA PROPAGACIN ASCENDENTE DEL CNCER RECTAL AVANZADO DESPUS DE LA RADIOQUIMIOTERAPIA PREOPERATORIA

ANTECEDENTES:Es un debate muy antiguo si las metástasis en los ganglios pélvicos laterales deben considerarse una enfermedad regional o sistémica. Si bien estudios japoneses anteriores las consideran como una enfermedad locorregional, en los países de occidente se las considera como una enfermedad sistémica por la cual no se realiza disección de ganglios pélvicos laterales después de una radioquimioterapia preoperatoria.OBJETIVOS:Evaluar si la metástasis en los ganglios pélvicos laterales se consideran como enfermedad sistémica o enfermedad regional susceptible de resección curativa.DISEÑO:Análisis retrospectivo de una base de datos recopilada prospectivamente.AJUSTE:Este estudio se realizó en un centro oncológico terciario.PACIENTES:616 pacientes consecutivos se sometieron a excisión total del mesorrecto curativa sola o con disección de los ganglios pélvicos laterales después de radioquimioterapia preoperatoria en casos de cáncer de recto localmente avanzado entre 2011 y 2019.PRINCIPALES MEDIDAS DE RESULTADO:Sobrevida global y libre de enfermedad a 3 años.RESULTADOS:Un total de 360 pacientes se sometieron a excisión total del mesorrecto y 160 pacientes se sometieron a excisión total del mesorrecto con disección de ganglios pélvicos laterales.No hubo diferencias en la sobrevida libre de enfermedad a 3 años (p = 0,844) ni en las tasas de sobrevida general (p = 0,921) entre los grupos. Los pacientes con metástasis en los ganglios pélvicos laterales mostraron una sobrevida libre de enfermedad similar a aquellos con metástasis en los ganglios linfáticos perirrectales que se encontraban en el grupo de excisión total del mesorrecto.En el análisis de subgrupos, los pacientes con metástasis en los ganglios pélvicos ilíacos internos mostraron una sobrevida libre de enfermedad comparable a aquellos con afección de los ganglios perirrectales y los pacientes con otras metástasis en los ganglios pélvicos laterales mostraron una sobrevida libre de enfermedad similar a aquellos con afección de los ganglios intermedios.En el grupo de disección de los ganglios pélvicos laterales, la tasa de metástasis en dichos ganglios fué del 32,5%. En el análisis multivariado, < de 8 ganglios pélvicos laterales resecados unilateralmente y el estadio ypT avanzado se asociaron significativamente con una menor sobrevida libre de enfermedad.LIMITACIÓN:El diseño retrospectivo del estudio.CONCLUSIONES:Las metástasis linfáticas laterales mostraron resultados oncológicos similares a la diseminación ascendente, especialmente las metástasis en los ganglios linfáticos perirrectales. Se requieren grandes estudios de cohortes con seguimiento a largo plazo para confirmar estos resultados. (Traducción-Dr. Xavier Delgadillo ).

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.

Preoperative lateral lymph node features and impact on local recurrence after neoadjuvant chemoradiotherapy and total mesorectal excision for locally advanced rectal cancer: results from a multicentre international cohort study

AIM

Locally advanced rectal cancer (LARC) is commonly treated with neoadjuvant chemoradiotherapy (nCRT) and total mesorectal excision (TME) to reduce local recurrence (LR) and improve survival. However, LR, particularly associated with lateral lymph node (LLN) involvement, remains a concern. The aim of this study was to investigate preoperative factors associated with LLN involvement and their impact on LR rates in LARC patients undergoing nCRT and curative surgery.

METHOD

This multicentre retrospective study, including four academic high-volume institutions, involved 301 consecutive adult LARC patients treated with nCRT and curative surgery between January 2014 and December 2019 who did not undergo lateral lymph node dissection (LLND). Baseline and restaging pelvic MRIs were evaluated for suspicious LLNs based on institutional criteria. Patients were divided into two groups: cLLN+ (positive nodes) and cLLN- (no suspicious nodes). Primary outcome measures were LR and lateral local recurrence (LLR) rates at 3 years.

RESULTS

Among the cohort, 15.9% had suspicious LLNs on baseline MRI, and 9.3% had abnormal LLNs on restaging MRI. At 3 years, LR and LLR rates were 4.0% and 1.0%, respectively. Ten out of 12 (83.3%) patients with LR showed no suspicious LLNs at the baseline MRI. Abnormal LLNs on MRI were not independent risk factors for LR, distant recurrence or disease-free survival.

CONCLUSION

Abnormal LLNs on baseline and restaging MRI assessment did not impact LR and LLR rates in this cohort of patients with LARC submitted to nCRT and curative TME surgery.

Robotic and laparoscopic salvage lateral pelvic node dissection for the treatment of recurrent rectal cancer

BACKGROUND

The lateral pelvic sidewall is a major site of local recurrence after radical resection of rectal cancer. Salvage lateral pelvic node dissection (LPND) may be the only way to eliminate recurrent lateral pelvic nodes (LPNs). This study aimed to describe the technical details of robotic and laparoscopic salvage LPND and assess the short-term clinical and oncological outcomes in patients with recurrent LPNs who underwent salvage LPND by a minimally invasive approach for curative intent.

METHODS

Between September 2010 and 2019, 36 patients who underwent salvage surgery for LPN recurrence were retrospectively analyzed from a prospectively maintained database. Patients' characteristics, index operation, MRI findings, and perioperative and pathological outcomes were analyzed.

RESULTS

Eleven and 14 patients underwent robotic and laparoscopic salvage LPND, respectively. Eight patients (32.0%) underwent a combined salvage operation for resectable extra-pelvic sidewall metastases. There were four cases of open-conversion during the laparoscopic approach due to uncontrolled bleeding of iliac vessels. In these patients, metastatic LPNs were suspected of iliac vessel invasion and were found to be larger in size (median 15 mm; range 12-20) than that in patients who underwent successful LPND using the minimally invasive approach (median 10 mm; range 5-20). The median number of metastatic LPNs and harvested LPNs was 1 (range 0-3) and 6 (range 1-16), respectively. Six patients (24.0%) experienced postoperative complications including lymphoceles and voiding difficulties. During the follow-up (median 44.6 months; range 24.0-87.7), eight patients developed recurrences, mainly the lung and para-aortic lymph nodes, and one patient developed pelvic sidewall recurrence after laparoscopic salvage LPND. The 3-year disease-free survival and overall survival after salvage LPND were 66.4% and 79.2%, respectively.

CONCLUSIONS

Robotic and laparoscopic salvage LPND for recurrent LPNs are safe and feasible with favorable short-term surgical outcomes. However, the surgical approach should be carefully chosen in patients with large-sized and invasive recurrent LPNs.

Metabolic and magnetic resonance imaging: complementary modalities for the preoperative assessment of lateral pelvic lymph nodes in rectal cancer

BACKGROUND

The management of lateral pelvic lymph nodes for rectal cancer is a topical and controversial issue. The aim of this study was to assess the relationship between lateral pelvic lymph node features on magnetic resonance imaging (MRI) and positron emission tomography-computed tomography (PET-CT) with oncological outcomes in patients with rectal cancer.

METHODS

A retrospective analysis of 284 patients with primary locally advanced rectal cancer treated with neoadjuvant therapy and surgical resection with curative intent between January 2003 and Dec 2018 was undertaken. From this study population, a select cohort of 77 patients with abnormal lateral pelvic lymph nodes on preoperative imaging had imaging re-analysed by radiologists blinded to clinical outcomes. Pre and post neoadjuvant therapy MRI and PET-CT lateral pelvic lymph node features were correlated with oncological outcomes.

RESULTS

A lateral pelvic lymph node short axis size ≥5 mm on post neoadjuvant therapy MRI was a significant predictor of worse 3-year local recurrence free survival (HR 8.35, P = 0.001). Lateral pelvic lymph node avidity on post neoadjuvant therapy PET-CT was a significant predictor of worse 3-year distant recurrence free survival (HR 5.62, P = 0.001). No correlation of oncological outcomes with overall survival was identified.

CONCLUSION

Lateral pelvic lymph node imaging features on post-neoadjuvant therapy MRI and PET-CT predicted those at risk of rectal cancer recurrence. Further studies are required to confirm these findings that suggest restaging MRI and PET-CT are complementary modalities for the preoperative assessment of lateral pelvic lymph nodes in rectal cancer.

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.

Predictors and histological effects of preoperative chemoradiotherapy for rectal cancer and control of lateral lymph node metastasis

Introduction

Standard treatment strategy for low rectal cancer in Japan is different from Western countries. Total mesorectum excision (TME) + lateral lymph node dissection (LLND) is mainly carried out in Japan, whereas neoadjuvant chemoradiotherapy (nCRT) + TME is selected in Western countries. There is no clear definition of preoperative diagnosis of lateral lymph node metastasis. If we can predict lateral lymph node swelling that can be managed by nCRT from lateral lymph node swelling that require surgical resection, clinical benefit is significant. In the current study we assessed characteristics of the lateral lymph node recurrence (LLNR) and LLND that can be managed by nCRT.

Patients and Methods

Patients with low rectal cancer (n = 168) underwent nCRT between 2009 and 2016. We evaluated CEA, neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), and lateral lymph node short axis pre and post nCRT, respectively, and also evaluated tumor shrinkage rate, tumor regression grade (TRG). We evaluated the relationship between each and LLNR.

Results

LLND was not carried out all patients. Factors associated with LLNR were PLR and lymph node short axis pre and post nCRT. (p = 0.0269, 0.0278, p < 0.0001, p < 0.0001, respectively). Positive recurrence cut-off values of lateral lymph node short-axis calculated were 11.6 mm pre nCRT and 5.5 mm post nCRT.

Conclusion

Results suggest that PLR before and after CRT was associated with control of LLNR, and LLND should be performed on lateral lymph nodes with short-axis of 5 mm and 11 mm pre and post nCRT.

Oncologic benefit of adjuvant chemotherapy for locally advanced rectal cancer after neoadjuvant chemoradiotherapy and curative surgery with selective lateral pelvic lymph node dissection: An international retrospective cohort study

INTRODUCTION

Intensive local treatment comprising total mesorectal excision (TME) with selective lateral pelvic lymph node dissection (LPND) after neoadjuvant chemoradiotherapy (CRT) for locally advanced rectal cancer (LARC) has received attention among clinicians treating rectal cancer. It remains unclear whether adjuvant chemotherapy (ACT) after intensive local treatment is beneficial for these patients. We evaluated the oncologic benefit of ACT for patients with LARC who received intensive local treatment.

MATERIALS AND METHODS

This international multicentre retrospective cohort study included 737 patients treated in Japan and Korea between 2010 and 2017. The effectiveness of ACT on recurrence-free survival (RFS) was evaluated using univariable and multivariable Cox proportional hazards models, with subgroup analyses to identify subpopulations potentially benefiting from ACT.

RESULTS

The median follow-up was 49 months; the 5-year RFS and local recurrence rates for the entire cohort were 72.1% and 4.9%, respectively; 514 patients (69.7%) received adjuvant chemotherapy, without an oncologic benefit (hazard ratio, 1.14; 95% confidence interval [CI]: 0.79-1.68) demonstrated in the multivariable Cox regression analysis. In subgroup analyses, the distributions of the 95% CI in patients aged ≥70 years and those with ypStage 0 tended to place a disproportionate emphasis that favoured the non-ACT treatment strategy.

CONCLUSION

Despite achieving good local control with intensive local treatment strategy, the effectiveness of ACT for the LARC patients with CRT followed by TME with selective LPND was not proved. Elderly patients and those with ypStage0 may not receive benefit from ACT after CRT and TME ± LPND.

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.

Lymph Nodes Evaluation in Rectal Cancer: Where Do We Stand and Future Perspective

The assessment of nodal involvement in patients with rectal cancer (RC) is fundamental in disease management. Magnetic Resonance Imaging (MRI) is routinely used for local and nodal staging of RC by using morphological criteria. The actual dimensional and morphological criteria for nodal assessment present several limitations in terms of sensitivity and specificity. For these reasons, several different techniques, such as Diffusion Weighted Imaging (DWI), Intravoxel Incoherent Motion (IVIM), Diffusion Kurtosis Imaging (DKI), and Dynamic Contrast Enhancement (DCE) in MRI have been introduced but still not fully validated. Positron Emission Tomography (PET)/CT plays a pivotal role in the assessment of LNs; more recently PET/MRI has been introduced. The advantages and limitations of these imaging modalities will be provided in this narrative review. The second part of the review includes experimental techniques, such as iron-oxide particles (SPIO), and dual-energy CT (DECT). Radiomics analysis is an active field of research, and the evidence about LNs in RC will be discussed. The review also discusses the different recommendations between the European and North American guidelines for the evaluation of LNs in RC, from anatomical considerations to structured reporting.

Prospective study to assess the role of FDG PET/CT in detecting systemic metastatic spread in rectal cancers with lateral pelvic lymph nodes

INTRODUCTION

The utility of positron emission tomography (PET) in detecting additional M1 patients over conventional staging modalities is not known in rectal cancer patients with enlarged lateral pelvic nodes.

METHODS

Prospective, single center, single-arm interventional study of consecutive rectal cancer patients that had baseline lateral pelvic nodes on MRI (>10 mm) between February 2017 to December 2018. Such patients underwent PET after confirming non-metastatic status on CT of thorax and abdomen. Primary outcome measure was additional M1 sites detected on PET. A 10% distant metastasis rate was expected with 80% confidence interval (CI) set at 5% as the lower limit.

RESULTS

44 patients were included and the concordance between MRI and PET in detection of lateral nodes was 97.7% (43 patients). Additional sites of metastasis were detected in 5 patients (11.36%; 80% CI - 5.63%-20.6%), and there was a change in treatment plan in 7 (15.9%). The number needed to treat (NNT) for PET scans to detect additional metastatic sites and change treatment were 9 and 6 respectively. There was a change in treatment intent (curative to palliative) in 2 patients (4.5%, NNT - 22).

CONCLUSION

In rectal cancer patients with LPLN, the use of FDG-PET-CT over conventional staging studies led to the detection of additional extra-pelvic metastasis in 11.4% and changed the treatment plan in 15.9%. This met the pre-defined threshold to endorse the use of PET-CT in patients that match the study characteristics.

Stepwise Improvement of Surgical Quality in Robotic Lateral Pelvic Node Dissection: Lessons From 100 Consecutive Patients With Locally Advanced Rectal Cancer

BACKGROUND

Lateral pelvic node dissection has significant technical difficulty and a high incidence of surgical morbidity. A steep learning curve is anticipated in performing lateral pelvic node dissection. However, no study has previously analyzed the learning curve and surgical skill acquisition for this complex procedure.

OBJECTIVES

We aimed to evaluate the learning process for performing robotic total mesorectal excision with lateral pelvic node dissection in patients with rectal cancer.

DESIGN

This is a retrospective analysis of a prospectively collected database.

SETTING

This study was conducted at a tertiary cancer center.

PATIENTS

A total of 100 patients who underwent robotic total mesorectal excision with lateral pelvic node dissection between 2011 and 2017 were included.

MAIN OUTCOME MEASURES

A cumulative sum analysis was calculated based on the number of unilateral retrieved lateral pelvic nodes. Operative time, estimated bloodloss, lateral pelvic node metastatic rate, postoperative morbidities, and local recurrence were also analyzed.

RESULTS

Cumulative sum modeling suggested 4 learning phases: learning I (33 patients), learning II (19 patients), consolidation (30 patients), and competence (18 patients). In the consolidation and competence phases, we adopted fluorescence imaging and standardized the surgical procedure on the basis of anatomical planes. The competence phase had the greatest number of unilateral retrieved lateral pelvic nodes (12.8 vs 4.9, 8.2, and 10.4; p < 0.001). Urinary complications, including urinary retention and postoperative α-blocker usage, were more frequently observed in learning phase I than in the competence phase (39.4% vs 16.7%, p = 0.034). During the median follow-up of 44.2 months, local recurrence in the pelvic sidewall was observed in 4 patients from learning phase I and in 1 patient from learning phase II.

LIMITATIONS

This study was limited by its retrospective design.

CONCLUSION

Completeness of the lateral pelvic node dissection procedure increased with the surgeon's experience and as new imaging systems and surgical technique standardization were implemented. Further studies are warranted to determine the oncologic outcomes associated with each phase. See Video Abstract at http://links.lww.com/DCR/B774.

MEJORA GRADUAL DE LA CALIDAD QUIRRGICA EN LA DISECCIN LINFTICA PLVICA LATERAL ROBTICA LECCIONES DE PACIENTES CONSECUTIVOS CON CNCER DE RECTO LOCALMENTE AVANZADO

ANTECEDENTES:La disección linfática pélvica lateral tiene una dificultad técnica significativa y una alta incidencia de morbilidad quirúrgica. Se prevé una curva de aprendizaje muy pronunciada al realizar la disección linfática pélvica lateral. Sin embargo, ningún estudio ha analizado previamente la curva de aprendizaje y la adquisición de habilidades quirúrgicas para este procedimiento.OBJETIVOS:Nuestro objetivo fue evaluar el proceso de aprendizaje para realizar la escisión total de mesorrecto robótica con disección linfática pélvica lateral en pacientes con cáncer de recto.DISEÑO:Este es un análisis retrospectivo de una base de datos recopilada prospectivamente.AJUSTE:Este estudio se realizó en un centro oncológico terciario.PACIENTES:Un total de 100 pacientes fueron sometidos a escisión total de mesorrecto robótica con disección linfática pélvica lateral entre 2011 y 2017.PRINCIPALES MEDIDAS DE DESENLACE:Se calculó un análisis de suma acumulativa basado en el número unilateral de ganglios pélvicos laterales recuperados. También se analizaron el tiempo operatorio, la pérdida de sangre estimada, la tasa de metástasis ganglionares pélvicas laterales, las morbilidades postoperatorias y la recidiva local.RESULTADOS:El modelado total acumulativo sugirió cuatro fases de aprendizaje: aprendizaje I (33 pacientes), aprendizaje II (19 pacientes), consolidación (30 pacientes) y competencia (18 pacientes). En las fases de consolidación y competencia, adoptamos imágenes de fluorescencia y estandarizamos el procedimiento quirúrgico basado en planos anatómicos, respectivamente. La fase de competencia tuvo el mayor número de ganglios pélvicos laterales recuperados unilateralmente (12,8 frente a 4,9, 8,2 y 10,4; p < 0,001). Las complicaciones urinarias, incluida la retención urinaria y el uso posoperatorio de bloqueadores beta, se observaron con más frecuencia en la fase de aprendizaje I que en la fase de competencia (39,4% frente a 16,7%, p = 0,034). Durante la mediana de seguimiento de 44,2 meses, se observó una recidiva local en la pared lateral pélvica en cuatro pacientes de la fase de aprendizaje I y en un paciente de la fase de aprendizaje II.LIMITACIONES:Este estudio estuvo limitado por su diseño retrospectivo.CONCLUSIÓNES:La completitud del procedimiento de disección linfática pélvica lateral aumentó con la experiencia del cirujano y a medida que se implementaron nuevos sistemas de imágenes y estandarización de técnicas quirúrgicas. Se necesitan más estudios para determinar los resultados oncológicos asociados con cada fase. Consulte Video Resumen en http://links.lww.com/DCR/B774.

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.

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.

Extended Lymphadenectomy in Locally Advanced Rectal Cancers: A Systematic Review

Purpose

The surgical treatment of advanced low rectal cancer remains controversial. Extended lymphadenectomy (EL) is the preferred option in the East, especially in Japan, while neoadjuvant radiotherapy is the treatment of choice in the West. This review was undertaken to review available evidence supporting each of the therapies.

Methods

All studies looking at EL were included in this review. A comprehensive search was conducted as per PRISMA guidelines. Primary outcome was defined as 5-year overall survival, with secondary outcomes including 3-year overall survival, 3- and 5-year disease-free survival, length of operation, and number of complications.

Results

Thirty-one studies met the inclusion criteria. There was no significant publication bias. There was statistically significant difference in 5-year survival for patient who underwent EL (odds ratio, 1.34; 95 confidence interval, 0.09–0.5; P=0.006). There were no differences noted in secondary outcomes except for length of the operations.

Conclusion

There is evidence supporting EL in rectal cancer; however, it is difficult to interpret and not easily transferable to a Western population. Further research is necessary on this important topic.

Lateral pelvic lymph nodes for rectal cancer: A review of diagnosis and management

The current status and future prospects for diagnosis and treatment of lateral pelvic lymph node (LPLN) metastasis of rectal cancer are described in this review. Magnetic resonance imaging (MRI) is recommended for the diagnosis of LPLN metastasis. A LPLN-positive status on MRI is a strong risk factor for metastasis, and evaluation by MRI is important for deciding treatment strategy. LPLN dissection (LPLD) has an advantage of reducing recurrence in the lateral pelvis but also has a disadvantage of complications; therefore, LPLD may not be appropriate for cases that are less likely to have LPLN metastasis. Radiation therapy (RT) and chemoradiation therapy (CRT) have limited effects in cases with suspected LPLN metastasis, but a combination of preoperative CRT and LPLD may improve the treatment outcome. Thus, RT and CRT plus selective LPLD may be a rational strategy to omit unnecessary LPLD and produce a favorable treatment outcome.

Malignant Features in Pretreatment Metastatic Lateral Lymph Nodes in Locally Advanced Low Rectal Cancer Predict Distant Metastases

INTRODUCTION

Pretreatment enlarged lateral lymph nodes (LLN) in patients with locally advanced low rectal cancer are predictive for local recurrences after neoadjuvant (chemo)radiotherapy (n(C)RT) followed by total mesorectal excision (TME). Not much is known of the impact on oncological outcomes when in addition malignant features are present in enlarged LLN.

PATIENTS AND METHODS

A multicenter retrospective cohort study was conducted at five tertiary referral centers in the Netherlands and Australia. All patients were diagnosed with locally advanced low rectal cancer with LLN on pretreatment magnetic resonance imaging (MRI) and underwent n(C)RT followed by TME. LLN were considered enlarged with a short axis of ≥ 5 mm. Malignant features were defined as nodes with internal heterogeneity and/or border irregularity. Outcomes of interest were local recurrence-free survival (LRFS), distant metastatic-free survival (DMFS), and overall survival (OS).

RESULTS

Out of 115 patients, the majority was male (75%) and the median age was 64 years (range 26-85 years). Median pretreatment LLN short axis was 7 mm (range 5-28 mm), and 60 patients (52%) had malignant features. After a median follow-up of 47 months, patients with larger LLN (7 + mm) had a worse LRFS (p = 0.01) but no difference in DMFS (p = 0.37) and OS (p = 0.54) compared with patients with smaller LLN (5-6 mm). LLN patients with malignant features had no difference in LRFS (p = 0.20) but worse DMFS (p = 0.004) and OS (p = 0.006) compared with patients without malignant features in the LLN. Cox regression analysis identified LLN short axis as an independent factor for LR. Malignant features in LLN were an independent factor for DMFS.

CONCLUSION

The current study suggests that pretreatment enlarged LLN that also harbor malignant features are predictive of a worse DMFS. More studies will be required to further explore the role of malignant features in LLN.

Prognostic Impact of Lateral Pelvic Node Dissection on the Survival of Patients in Low Rectal Cancer Subgroups Based on Lymph Node Size

BACKGROUND

Lateral pelvic node (LPN) dissection (LPND) is considered a promising technique for treating low rectal cancer; however, there is insufficient evidence of its prognostic value. Using centrally reviewed preoperative pelvic magnetic resonance (MR) images, this study aimed to find the patient population who has benefited from LPND.

PATIENTS AND METHODS

MR images of patients from 69 institutes with stage II-III low rectal cancer were reviewed by experienced radiologists. Recurrence-free survival (RFS), overall survival (OS), and short-term outcomes were measured.

RESULTS

In total, 731 preoperative MR images were reviewed (excluding patients with short-axis LPN ≥ 10 mm). Of these, 322 underwent total mesorectum excision (TME) without LPND (non-LPND group), and 409 underwent TME with LPND (LPND group). Preoperative treatment was performed for 40% and 25% of patients in the non-LPND and LPND groups, respectively. The incidence of postoperative complications was higher in the LPND group (44.5%) than in the non-LPND group (33.2%; P = 0.002). Among patients with LPNs < 5 mm, OS and RFS curves were not significantly different between the groups. Among patients with LPNs ≥ 5 mm, the LPND group had significantly higher 5-year OS and RFS than the non-LPND group (OS: 81.9% versus 67.3%; RFS: 69.4% versus 51.6%). On multivariate analysis of LPN ≥ 5 mm cases, LPND was independently associated with RFS.

CONCLUSIONS

Despite the high incidence of postoperative complications, this study showed the prognostic impact of LPND on low rectal cancer patients with LPNs (≥ 5 mm, < 10 mm short axis) measured by experienced radiologists. Trial registration UMIN-ID: UMIN000013919.

Comparison of Short-term Results after Laparoscopic Complete Mesocolic Excision and Standard Colectomy for Right-Sided Colon Cancer: Analysis of a Western Center Cohort

Purpose

Laparoscopic complete mesocolic excision (CME) right colectomy is a technically demanding procedure infrequently employed in Western centers. This retrospective cohort study aims to analyze the safety of laparoscopic CME colectomy compared to standard colectomy for right-sided colon cancer in a Western series.

Methods

Prospectively collected data from 60 patients who underwent laparoscopic CME right colectomy were compared to the ones of 55 patients who underwent laparoscopic standard right colectomy.

Results

No differences in clinical characteristics were observed between the CME and standard right colectomy groups. No differences were demonstrated in terms of blood loss (P = 0.060), intraoperative complications (P = 1), conversion rate (P = 0.102), and operative time (P = 0.473). No deaths were observed in either group, while complication rate was 40.0% in the CME and 49.1% in the standard group (P = 0.353). Severe complications occurred in 10.0% vs. 9.1% (P = 0.842), redo surgery in 5.0% vs. 7.3% (P = 0.708), and unplanned readmission in 5.0% vs. 5.5% (P = 1) after CME and standard colectomy, respectively. A significant difference in favor of CME was observed in the total length of specimen (P < 0.001), proximal (P = 0.018), and distal margins (P = 0.037). The number of lymph nodes harvested was significantly higher in the CME group (27 vs. 22, P = 0.037).

Conclusion

In Western series, where patients have less favorable clinical characteristics, laparoscopic CME allows to obtain better quality surgical specimens and comparable short-term outcomes compared to standard right colectomy.

Optimal Size Criteria for Lateral Lymph Node Dissection After Neoadjuvant Chemoradiotherapy for Rectal Cancer

BACKGROUND

Although chemoradiotherapy followed by radical surgery without lateral lymph node dissection is the current standard treatment in patients with rectal cancer, recent studies have demonstrated the benefits of adding lateral lymph node dissection to total mesorectal excision in patients with suspected lateral lymph node metastasis. However, the optimal indication for lateral lymph node dissection after chemoradiotherapy has not been determined.

OBJECTIVE

This study aimed to establish the optimal indication for lateral lymph node dissection after chemoradiotherapy in patients with rectal cancer.

DESIGN

This is a retrospective study.

SETTINGS

This study was conducted at a single referral hospital.

PATIENTS

A total of 279 patients with rectal cancer who underwent chemoradiotherapy followed by radical surgery between 2007 and 2018 were retrospectively enrolled.

MAIN OUTCOME MEASURES

The largest lateral lymph nodes on CT were retrospectively assessed and compared with the pathologic results of dissected lateral lymph nodes and recurrences in lateral lymph node areas.

RESULTS

The incidence of lateral lymph node metastasis after chemoradiotherapy was estimated to be 9.3%. Although patients with lateral lymph node metastasis frequently developed distant recurrence, 40.4% survived for >5 years without recurrence. An analysis of the lateral lymph node sizes showed that lateral lymph node size ≥8 mm before chemoradiotherapy was the optimal criterion for lateral lymph node dissection, with a sensitivity and specificity of 92.3% and 78.7%. Using this criterion, 72.0% of the patients could be spared lateral lymph node dissection.

LIMITATIONS

Because of the retrospective nature of the present study, the selection of patients who underwent lateral lymph node dissection was biased.

CONCLUSIONS

The optimal indication for lateral lymph node dissection was lateral lymph node size ≥8 mm before chemoradiotherapy. Cancer could be eradicated in >30% of patients with lateral lymph node metastasis by dissecting metastatic lateral lymph nodes. See Video Abstract at http://links.lww.com/DCR/B428.

CRITERIOS DE TAMAO PTIMO PARA LA DISECCIN DE GANGLIOS LINFTICOS LATERALES DESPUS DE LA QUIMIORRADIOTERAPIA NEOADYUVANTE PARA EL CNCER DE RECTO

ANTECEDENTES:Aunque la quimiorradioterapia seguida por cirugía radical sin disección de ganglios linfáticos laterales es el tratamiento estándar actual en pacientes con cáncer de recto, estudios recientes han demostrado beneficios de agregar disección de ganglios linfáticos laterales a la escisión mesorrectal total en pacientes con sospecha de metástasis de ganglios linfáticos laterales. Sin embargo, no se ha determinado la indicación óptima para la disección de los ganglios linfáticos laterales después de la quimiorradioterapia.OBJETIVO:Este estudio tuvo como objetivo establecer la indicación óptima para la disección de los ganglios linfáticos laterales después de la quimiorradioterapia en pacientes con cáncer de recto.DISEÑO:Estudio retrospectivo.ENTORNO CLINICO:Este estudio se realizó en un solo hospital de referencia.PACIENTES:Se inscribieron retrospectivamente un total de 279 pacientes con cáncer de recto que se sometieron a quimiorradioterapia seguida por cirugía radical entre 2007 y 2018.PRINCIPALES MEDIDAS DE VALORACION:Los ganglios linfáticos laterales más grandes en la tomografía computarizada se evaluaron retrospectivamente y se compararon con los resultados patológicos de los ganglios linfáticos laterales disecados y recidivas en las áreas de los ganglios linfáticos laterales.RESULTADOS:Se estimó que la incidencia de metástasis en los ganglios linfáticos laterales después de la quimiorradioterapia fue del 9,3%. Aunque los pacientes con metástasis en los ganglios linfáticos laterales con frecuencia desarrollaron recurrencia a distancia, el 40,4% sobrevivió durante más de 5 años sin recurrencia. Un análisis de los tamaños de los ganglios linfáticos laterales mostró que la mayor dimensión de los ganglios linfáticos laterales ≥ 8 mm antes de la quimiorradioterapia eran el criterio óptimo para la disección de los ganglios linfáticos laterales, con una sensibilidad y especificidad del 92,3% y 78,7%, respectivamente. Utilizando este criterio, el 72,0% de los pacientes podría evitarse la disección de los ganglios linfáticos laterales.LIMITACIONES:Debido a la naturaleza retrospectiva del presente estudio, la selección de pacientes que fueron sometidos a disección de ganglios linfáticos laterales fue sesgada.CONCLUSIÓN:La indicación óptima para la disección de los ganglios linfáticos laterales fue la dimensión mayor de los ganglios linfáticos laterales ≥ 8 mm antes de la quimiorradioterapia. El cáncer se podría erradicar en más del 30% de los pacientes con metástasis en los ganglios linfáticos laterales disecando los ganglios linfáticos laterales metastásicos. Consulte Video Resumen en http://links.lww.com/DCR/B428.

Long-term clinical outcomes of total mesorectal excision and selective lateral pelvic lymph node dissection for advanced low rectal cancer: a comparative study of a robotic versus laparoscopic approach

BACKGROUND

The long-term outcomes of minimally invasive lateral pelvic lymph node dissection (LPND) are not completely known. The aim of this study was to compare long-term outcomes between robotic and laparoscopic LPND in low rectal cancer patients with suspected lymph node metastasis in the pelvic sidewall.

METHODS

We retrospectively reviewed the records of all rectal cancer patients who had laparoscopic or robotic total mesorectal excision (TME) with LPND between March 2006 and June 2016. Stage IV patients were excluded. The outcomes of patients who had laparoscopic and robotic TME with LPND were compared.

RESULTS

Twenty-nine patients had laparoscopic LPND and 70 had robotic LPND. No significant differences in patient characteristics were observed between the two groups. The urinary retention rate was lower in the robotic group than in the laparoscopic group (7.1% vs. 24.1%; p = 0.043). During a median follow-up of 44.3 months, the overall recurrence rates were 48.3% and 31.4% in the laparoscopic and robotic groups, respectively (p = 0.175). The 5-year disease-free survival rates were 50.4% and 67.0% in the laparoscopic and robotic groups, respectively (p = 0.227). The 5-year overall survival rates were 65.0% and 92.2% in the laparoscopic and robotic groups, respectively (p = 0.017).

CONCLUSIONS

Robotic TME with LPND is safe and feasible. In particular, it is associated with lower urinary retention. Robotic TME with LPND might yield a similar local recurrence rate and 5-year disease-free survival, but favorable long-term overall survival as compared to the laparoscopic approach. However, considering the retrospective nature and both major variables of TME and LPND involved together, this should be cautiously interpreted.

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.

Neoadjuvant (chemo)radiotherapy and Lateral Node Dissection: Is It Mutually Exclusive?

The importance of total mesorectal excision (TME) has been the global standard of care in patients with rectal cancer. However, there is no universal strategy for lateral lymph nodes (LLN). The treatment of the lateral compartment remains controversial and has gone to the opposite directions between Eastern and Western countries in the past decades. In the East, mainly Japan, surgeons consider LLN metastases as regional disease and have performed TME with lateral lymph node dissection (LLND) without neoadjuvant (chemo)radiotherapy ([C]RT) in patients with clinical Stage II/III rectal cancer below the peritoneal reflection. In the West, neoadjuvant radiotherapy or has been the standard, and surgeons do not perform LLND assuming the (C)RT can sterilize most lateral lymph node metastasis (LLNM). Recent evidences show that lateral nodes are the major cause of local recurrence after (C)RT plus TME, and LLND reduces local recurrence particularly from the lateral compartment. Probably a combination of the two strategies, that is, neoadjuvant (C)RT plus LLND, would be needed to improve outcomes in patients with lateral nodal disease.

Current Surgical Strategies for the Treatment of Rectal Adenocarcinoma and the Risk of Local Recurrence

BACKGROUND

Despite new medical and surgical strategies, 5-year local recurrence of rectal adenocarcinoma was reported in up to 25% of cases. Therefore, we aimed to review surgical strategies for the prevention of local recurrences in rectal cancer.

SUMMARY

After implementation of the total mesorectal excision (TME), surgical resection of rectal adenocarcinoma with anterior resection or abdominoperineal excision (APE) allowed decrease in local recurrence (3% at 5 years). More recently, extralevator APE was described as an alternative to APE, decreasing specimen perforation and recurrence rate. Moreover, technique modifications were developed to optimize rectal resection, such as the laparoscopic or robotic approach, and transanal TME. However, the technical advantages conferred by these techniques did not translate into a decreased recurrence rate. Lateral lymph node dissection is another technique, which aimed at improving the long-term outcomes; nevertheless, there is currently no evidence to recommend its routine use. Strategies to preserve the rectum are also emerging, such as local excision, and may be beneficial for subgroups of patients. Key Messages: Rectal cancer management requires a multidisciplinary approach, and surgical strategy should be tailored to patient factors: general health, previous perineal intervention, anatomy, preference, and tumor characteristics such as stage and localization.

MRI of rectal cancer-relevant anatomy and staging key points

Rectal cancer has the eighth highest cancer incidence worldwide, and it is increasing in young individuals. However, in countries with a high human development index, mortality is decreasing, which may reflect better patient management, imaging being key. We rely on imaging to establish the great majority of clinical tumour features for therapeutic decision-making, namely tumour location, depth of invasion, lymph node involvement, circumferential resection margin status and extramural venous invasion. Despite major improvements in technique resulting in better image quality, and notwithstanding the dissemination of guidelines and examples of standardised reports, rectal cancer staging is still challenging on the day-to-day practice, and we believe there are three reasons. First, the normal posterior pelvic compartment anatomy and variants are not common knowledge to radiologists; second, not all rectal cancers fit in review paper models, namely the very early, the very low and the mucinous; and third, the key clinical tumour features may be tricky to analyse. In this review, we discuss the normal anatomy of the rectum and posterior compartment of the pelvis, systematise all rectal cancer staging key points and elaborate on the particularities of early, low and mucinous tumours. We also include our suggested reporting templates and a discussion of its comparison to the reporting templates provided by ESGAR and SAR.

Radiomics Approach Outperforms Diameter Criteria for Predicting Pathological Lateral Lymph Node Metastasis After Neoadjuvant (Chemo)Radiotherapy in Advanced Low Rectal Cancer

BACKGROUND

Advanced low rectal cancer has a non-negligible risk of lateral pelvic lymph node (LPLN) metastasis (LPLNM) and lateral local recurrence (LR) after neoadjuvant (chemo)radiotherapy and total mesorectal excision. LPLN dissection (LPLND) reduces LR but increases postoperative complications and sexual/urinary dysfunction.

OBJECTIVE

The aim of this study was to develop a new radiomics-based prediction model for LPLNM in patients with rectal cancer.

METHODS

A total of 247 patients with rectal cancer and enlarged LPLNs treated by (chemo)radiotherapy and LPLND were enrolled in this retrospective, multicenter study. LPLN radiomic features were extracted from pretreatment portal venous-phase computed tomography images. A radiomics score of LPLN was constructed based on the least absolute shrinkage and selection operator regression in a primary cohort of 175 patients. Model performance was assessed in terms of discrimination, calibration, and decision curve analysis, and was externally validated in 72 patients.

RESULTS

The radiomics score showed significantly better discrimination compared with pretreatment short-axis diameter measurements in both the primary (area under the curve [AUC] 0.91 vs. 0.83, p = 0.0015) and validation (AUC 0.90 vs. 0.80, p = 0.0298) cohorts. Decision curve analysis also indicated the superiority of the radiomics score. In a subanalysis of patients with a short-axis diameter ≥ 7 mm, the radiomics nomogram, incorporating the radiomics score and LPLN shrinkage to ≤ 4 mm, had better discrimination compared with a model incorporating only LPLN shrinkage in both cohorts.

CONCLUSIONS

Radiomics-based prediction modeling provides individualized risk estimation of LPLNM in rectal cancer patients treated with (chemo)radiotherapy, and outperforms measurements of pretreatment LPLN diameter.

Does adding lateral pelvic lymph node dissection to neoadjuvant chemotherapy improve outcomes in low rectal cancer?

PURPOSE

Lateral pelvic lymph node metastasis occurs in 15 to 20% of patients with locally advanced low rectal cancer which increases risk of local recurrence and reduced survival following neoadjuvant chemoradiotherapy (nCRT) and total mesorectal excision (TME). Adding lateral pelvic lymph node dissection (LPLND) could improve outcomes in those patients. This review aims to determine if the addition of LPLND to the conventional management of advanced rectal cancer would yield improved outcomes.

METHODS

OVID Medline, Cochrane, Clinicaltrials.gov , EMBASE, Clinicaltrialsregister.eu, Web of Knowledge and CABAbstracts were searched using the following keywords: 'lateral pelvic lymph node dissection', 'pelvis lymphadenectomy', 'chemoradi*', 'rectal cancer', 'rectal neoplasm', 'rectal carcinoma' and 'rectal tumour'. Studies were included if they were in English and included rectal cancer patients that had nCRT, rectal resection ± LPLND. Primary outcome was 3-year and 5-year local recurrence. Secondary outcome was 3-year and 5-year overall survival.

RESULTS

Six studies were identified with 1210 patients who had nCRT and TME, and 268 patients who had nCRT and rectal resection plus LPLND. Patients who had LPLND had non-significant lower 3-year and 5-year local recurrence rate compared with those who did not (p = 0.10 and p = 0.12, respectively). They demonstrated a lower 3-year overall survival but higher 5-year overall survival and both were not significant (p = 0.81 and p = 0.57, respectively).

CONCLUSION

Available evidence suggests that there is no significant reduction in local recurrence rates or improved survival from LPLND to the current treatment modalities. Further studies are required to define the role of lateral pelvic lymph node dissection in low rectal cancer.

Total mesorectal excision with and without lateral lymph node dissection: a systematic review of the literature

PURPOSE

Treatment of lateral lymph node metastasis in rectal cancer is still under debate. While these nodes are routinely resected by Japanese teams, neoadjuvant radiochemotherapy alone is performed in Western countries. We aimed to systematically report the current literature assessing the overall and disease-free survivals of patients with rectal cancer treated with total mesorectal resection (TME) with or without lateral lymph node dissection (LLND).

METHODS

MEDLINE/Pubmed, Embase, Cochrane, and Web of Science were searched from database implementation until 19 January 2019. Studies reporting overall survival or recurrence-free survival in patients with LLND for rectal cancer were included. We excluded studies including patients with recurrent rectal cancer, multivisceral resection, and/or without control group (patients with rectal surgery without LLND).

RESULTS

Eleven studies were included, accounting for a total of 4159 patients. Overall survival ranged between 55.6 and 92.6% for TME with LLND versus 49.2 and 90.2% for TME alone, with one study reporting statistically significant benefit of LLND. Recurrence-free survival ranged between 58.3 and 74.1% for TME with LLND versus 39.5 and 76.5% for TME alone. Two studies showed statistically significant differences between the two strategies, one randomized controlled trial showed improved recurrence-free survival in TME alone group (74.5% versus 74.1% with LLND at 5 years) and one observational retrospective study reported increased recurrence-free survival with more extensive resection (65.4% versus 39.5% without LLND, at 5 years).

CONCLUSION

Benefits of LLND are not clear and further randomized controlled trials should be performed to determine which strategy would allow improving survival in rectal cancer patients.

TRIAL REGISTRATION

The study protocol was registered in PROSPERO prior to study screening (CRD42019123181) and published in September 2019.

Total mesorectal excision plus lateral lymph node dissection vs TME on rectal cancer patients: a meta-analysis

OBJECTIVE

Our study is the first meta-analysis to compare total mesorectal excision (TME) plus lateral lymph node dissection (LLND) with TME on rectal cancer patients regarding outcomes including overall survival, disease-free survival, local recurrence, complications, urinary dysfunction, and sexual dysfunction.

METHODS

PubMed, Embase, and Cochrane library were searched for publications up to October 2019. Two investigators independently screened the studies for eligibility and extracted specific data. Relevant data were analyzed by Review Manager version 5.3.

RESULTS

Patients in TME + LLND group suffered more complications (OR = 1.48, 95% CI [1.07, 2.03], P = 0.02) compared with TME group; no significant difference was observed in overall survival (HR = 1.11, 95% CI [0.77, 1.61], P = 0.57), disease-free survival (HR = 1.05, 95% CI [0.85, 1.30], P = 0.64), local recurrence (OR = 0.93, 95% CI [0.56, 1.54], P = 0.78), and urinary dysfunction (OR = 1.60, 95% CI [0.66, 3.87], P = 0.3).

CONCLUSION

TME + LLND may cause more complications compared with TME on rectal cancer patients. However, the definite conclusion still requires more researches.

What is the role of lateral lymph node dissection in rectal cancer patients with clinically suspected lateral lymph node metastasis after preoperative chemoradiotherapy? A meta-analysis and systematic review

BACKGROUND

Local lateral recurrence (LLR) in rectal cancer is increasingly becoming a significant clinical issue. Preoperative neoadjuvant chemoradiotherapy (nCRT) and lateral lymph node dissection (LLND)-when each approach is separately executed-cannot cure lateral lymph node metastasis (LLNM). Here, we performed a meta-analysis to evaluate the efficacy of nCRT plus total mesorectal excision (TME) vs TME plus LLND after nCRT for rectal cancer.

METHODS

Standard databases (PubMed, Embase, MEDLINE, Cochrane Library, and Web of Science) were searched to identify all relevant studies comparing nCRT+TME and nCRT+TME+LLND. Data in the included studies were extracted, and intraoperative outcomes, postoperative complications, and oncological outcomes were evaluated.

RESULTS

Eight studies representing 1,896 patients (1,461 nCRT+TME vs 435 nCRT+TME+LLND) were included. We found that for patients with clinically suspected LLNM, the incidence of pathological LLNM was 27.8%, even after nCRT. LLND after nCRT was significantly associated with lower LLR (P = .02). Additional LLND yielded a longer operative time (P < .01) and increased the risk of urinary dysfunction (P < .01). Concerning other outcomes, no significant differences were identified between the two groups.

CONCLUSION

This is the first meta-analysis and systematic review of studies comparing nCRT+TME and nCRT+TME+LLND for rectal cancer patients. Although increasing operative time and the risk of urinary dysfunction (which might be ameliorated by minimally invasive procedures), the pooled results support the use of LLND after nCRT and TME for reducing LLR in patients with clinically suspected LLNM and provide another treatment option for high-risk patients.

Short term outcomes of minimally invasive selective lateral pelvic lymph node dissection for low rectal cancer

BACKGROUND

Pelvic recurrence after rectal cancer surgery is still a significant problem despite the introduction of total mesorectal excision and chemoradiation treatment (CRT), and one of the most common areas of recurrence is in the lateral pelvic lymph nodes. Hence, there is a possible role for lateral pelvic lymph node dissection (LPND) in rectal cancer.

AIM

To evaluate the short-term outcomes of patients who underwent minimally invasive LPND during rectal cancer surgery. Secondary outcomes were to evaluate for any predictive factors to determine lymph node metastases based on pre-operative scans.

METHODS

From October 2016 to November 2019, 22 patients with stage II or III rectal cancer underwent minimally invasive rectal cancer surgery and LPND. These patients were all discussed at a multidisciplinary tumor board meeting and most of them received neoadjuvant chemoradiation prior to surgery. All patients had radiologically positive lateral pelvic lymph nodes on the initial staging scans, defined as lymph nodes larger than 7 mm in long axis measurement, or abnormal radiological morphology. LPND was only performed on the involved side.

RESULTS

Majority of the patients were male (18/22, 81.8%), with a median age of 65 years (44-81). Eighteen patients completed neoadjuvant CRT pre-operatively. 18 patients (81.8%) had unilateral LPND, with the others receiving bilateral surgery. The median number of lateral pelvic lymph nodes harvested was 10 (3-22) per pelvic side wall. 8 patients (36.4%) had positive metastases identified in the lymph nodes harvested. The median pre-CRT size of these positive lymph nodes was 10mm. Median length of stay was 7.5 d (3-76), and only 2 patients failed initial removal of their urinary catheter. Complication rates were low, with only 1 lymphocele and 1 anastomotic leak. There was only 1 mortality (4.5%). There have been no recurrences so far.

CONCLUSION

Chemoradiation is inadequate in completely eradicating lateral wall metastasis and there are still technical limitations in accurately diagnosing metastases in these areas. A pre-CRT lymph node size of ≥ 10 mm is suggestive of metastases. LPND may be performed safely with minimally invasive surgery.

Update on indications for lateral lymph node dissection in the management of lower rectal cancer

The presence of lateral lymph node (LLN) metastasis was associated with higher local recurrence risk in patients with lower rectal cancer. The role of LLN dissection has not been fully determined despite prolonged debate that last for few decades. The practical difference between Japan and the West was the main culprit. Japanese used to rely on surgical removal of LLN as local control while the West believed that LLN dissection could be spared after giving neoadjuvant chemoradiotherapy. As time passed, it is getting more common to combine both treatments. With the quality improvement in magnetic resonance imaging, we can now predict the chance of LLN metastasis and evaluate the treatment response with good accuracy. Few large analyses have been published recently and provided us more insight into this topic. In this review, we summarized and provided an update on the latest evidence. We have proposed a treatment algorithm on the management of LLNs which may help clinical decision and provide idea for further research.

Diagnostic and management strategies for lateral pelvic lymph nodes in low rectal cancer-a review of the evidence

Patients with low rectal cancer who have enlarged lateral pelvic lymph nodes are known to have a worse prognosis. There is however uncertainty over what constitutes a lateral pelvic lymph node of clinical significance. As the main modality for the detection of such lymph nodes is magnetic resonance imaging (MRI), characteristics of these lateral lymph nodes identified may have prognostic value and assist with guiding treatment. Options to manage such lateral lymph nodes includes neoadjuvant chemoradiotherapy as well as lateral lymph node dissection. Surgery is extensive and may lead to significant morbidity to the patient. This review article evaluates diagnostic and management strategies in patients with lateral pelvic lymph nodes in low rectal cancer.

Lateral Nodal Features on Restaging Magnetic Resonance Imaging Associated With Lateral Local Recurrence in Low Rectal Cancer After Neoadjuvant Chemoradiotherapy or Radiotherapy

Importance

Previously, it was shown in patients with low rectal cancer that a short-axis (SA) lateral node size of 7 mm or greater on primary magnetic resonance imaging (MRI) resulted in a high lateral local recurrence (LLR) rate after chemoradiotherapy or radiotherapy ([C]RT) with total mesorectal excision (TME) and that this risk was lowered by a lateral lymph node dissection (LLND). The role of restaging MRI after (C)RT with regard to LLR risk and which specific patients might benefit from an LLND is not fully understood.

Objective

To determine the factors on primary and restaging MRI that are associated with LLR in low rectal cancer after (C)RT and to formulate specific guidelines on which patients might benefit from an LLND.

Design, Setting, and Participants

In this retrospective, multicenter, pooled cohort study, patients who underwent surgery for cT3 or cT4 low rectal cancer with a curative intent from 12 centers in 7 countries from January 2009 to December 2013 were included. All patients' MRIs were rereviewed according to a standardized protocol, with specific attention to lateral nodal features. The original cohort included 1216 patients. For this study, patients who underwent (C)RT and had a restaging MRI were selected, leaving 741 for analyses across 10 institutions, including 651 who underwent (C)RT with TME and 90 who underwent (C)RT with TME and LLND.

Main Outcomes and Measures

The main purpose was to identify the factors on primary and restaging MRI associated with LLR after (C)RT with TME. Whether high-risk patients might benefit in terms of LLR reduction from an LLND was also studied.

Results

Of the 741 included patients, 480 (64.8%) were male, and the mean (SD) age was 60.4 (12.0) years. An SA lateral node size of 7 mm or greater on primary MRI resulted in a 5-year LLR rate of 17.9% after (C)RT with TME. At 3 years, there were no LLRs in 28 patients (29.2%) with lateral nodes that were 4 mm or less on restaging MRI. Nodes that were 7 mm or greater on primary MRI and greater than 4 mm on restaging MRI in the internal iliac compartment resulted in a 5-year LLR rate of 52.3%, significantly higher compared with nodes in the obturator compartment of that size (9.5%; hazard ratio, 5.8; 95% CI, 1.6-21.3; P = .003). Compared with (C)RT with TME alone, treatment with (C)RT with TME and LLND in these unresponsive internal nodes resulted in a significantly lower LLR rate of 8.7% (hazard ratio, 6.2; 95% CI, 1.4-28.5; P = .007).

Conclusions and Relevance

Restaging MRI is important in clinical decision making in lateral nodal disease. In patients with shrinkage of lateral nodes from an SA node size of 7 mm or greater on primary MRI to an SA node size of 4 mm or less on restaging MRI, which occurs in about 30% of cases, LLND can be avoided. However, persistently enlarged nodes in the internal iliac compartment indicate an extremely high risk of LLR, and an LLND lowered LLR in these cases.

Oncological Outcomes of Patients with Locally Advanced Rectal Cancer and Lateral Pelvic Lymph Node Involvement

INTRODUCTION

The optimal management of patients with radiologically positive lateral pelvic lymph nodes in locally advanced rectal cancer remains unclear. We compared local recurrence rates and oncological outcomes of patients with locally advanced cancer with and without lateral pelvic lymph nodes.

METHODS

Patients who underwent curative surgery for stage III rectal adenocarcinoma between 2009 and 2014 and had a preoperative MRI at our institution as well as preoperative neoadjuvant treatment were included. Patients with positive lateral pelvic lymph nodes (iliac or obturator nodes) on preoperative MRI (LPND +) were compared to patients with no lateral pelvic nodal disease (LPND -). Data were collected from a prospectively maintained institutional database. Differences between the groups were compared in univariate analysis. Log-rank test was used to evaluate overall and disease-free survival between the groups.

RESULTS

A total of 125 patients met inclusion criteria with a mean age of 56.3 ± 12.2 and 75% were male. Median follow-up was 44 months (IQR 32, 106). Positive LPND was present on preoperative MRI in 43/125 (34.4%) patients who were in the LPND (+) group. Seventeen out of 43 patients had a post-neoadjuvant treatment MRI and 15 patients had a decrease in size of nodes or disappearance of LPND. On univariate analysis, LPND (+) and LPND (-) groups were comparable. Local recurrence rates were higher in the LPND (+) group, although this was not statistically significant (16.3% vs. 6%, p = 0.06). Overall and disease-free survival rates were comparable between the LPND (+) and LPND (-) groups (p = 0.97, p = 0.51).

CONCLUSIONS

Management of patients with advanced rectal cancer and radiologically positive lateral pelvic lymph nodes is challenging due to high local recurrence rates. Further studies are needed to develop care pathways for the optimal treatment processes.

Clinical Implications of Lymph Node Metastasis in Colorectal Cancer: Current Status and Future Perspectives

Lymph node metastasis is regarded as an indubitable prognostic factor for predicting disease recurrence and survival in patients with colorectal cancer. Lymph node status based on examination of a resected specimen is a key element of the current staging system and is also a crucial factor to determine use of adjuvant chemotherapy after surgical resection. However, the current tumor-node-metastasis (TNM) staging system only incorporates the number of metastatic lymph nodes in the N category. Numerous attempts have been made to supplement this simplified N staging including lymph node ratio, distribution of metastatic lymph nodes, tumor deposits, or extracapsular invasion. In addition, several attempts have been made to identify more specific prognostic factors in resected colorectal specimens than lymph node status. In this review, we will discuss controversies in lymph node staging and factors that may influence survival beyond lymph node status.

S122: impact of fluorescence and 3D images to completeness of lateral pelvic node dissection

BACKGROUND

Lateral pelvic lymph node dissection (LPND) is a technically demanding procedure. Consequently, there is a possibility of incomplete dissection of lateral pelvic lymph nodes (LPNs). We aimed to identify metastatic LPNs intraoperatively in real-time under dual guidance of fluorescence imaging and 3D lymphovascular reconstruction, and then to remove them completely.

METHODS

Rectal cancer patients who were scheduled to undergo LPND after preoperative chemoradiotherapy (CRT) were prospectively enrolled. We traced changes in suspected metastatic LPNs during preoperative CRT and defined them as index LPNs on post-CRT imaging studies. For fluorescence imaging, indocyanine green (ICG) at a dose of 2.5 mg was injected transanally around the tumor before the operation. For 3D reconstruction images, each patient underwent preoperative axial CT scan with contrast (0.6 mm slice thickness). These images were then manipulated with OsiriX. Index LPNs and essential structures in the pelvic sidewall, such as the obturator nerve, were reconstructed with abdominal arteries from 3D volume rendering. All surgical procedures were performed via laparoscopic or robotic approach.

RESULTS

From March to July 2017, ten rectal cancer patients underwent total mesorectal excision with LPND after preoperative CRT under dual image guidance. Bilateral LPND was performed in five patients. All index LPNs among ICG-bearing lymph nodes were clearly identified intraoperatively by matching with their corresponding 3D images. Pathologic LPN metastasis was confirmed in four patients (40.0%) and in five of the 15 dissected pelvic sidewalls (33.0%). All metastatic LPNs were identified among index LPNs. Four (80.0%) of the five metastatic LPNs were located in the internal iliac area.

CONCLUSION

Index LPNs among ICG-bearing lymph nodes in pelvic sidewall were clearly identified and completely removed by matching with their corresponding 3D reconstruction images. Further studies and long-term oncologic outcomes are required to determine the real impact of dual image guidance in LPND.

Phase II Trial of Neoadjuvant Chemotherapy, Chemoradiotherapy, and Laparoscopic Surgery with Selective Lateral Node Dissection for Poor-Risk Low Rectal Cancer

PURPOSE

The aim of this study is to evaluate the safety and efficacy of induction modified 5-fluorouracil, leucovorin, and oxaliplatin (mFOLFOX6) plus bevacizumab followed by S- 1-based chemoradiotherapy in magnetic resonance imaging (MRI)-defined poor-risk locally advanced low rectal cancer.

PATIENTS AND METHODS

This was a prospective phase II trial at a single comprehensive cancer center. The primary endpoint was the pathological complete response (pCR) rate. Eligible patients had clinical stage II-III low rectal adenocarcinoma with any of the following MRI-defined poor-risk features: circumferential resection margin (CRM) ≤ 1 mm, cT4, positive lateral nodes, mesorectal N2 disease, and/or requiring abdominoperineal resection. Patients received six cycles of mFOLFOX6 with 5 mg/kg bevacizumab followed by oral S-1 (80 mg/m²/day on days 1-14 and 22-35) plus radiotherapy (50.4 Gy). Surgery was conducted through a laparoscopic approach. Lateral node dissection was selectively added when the patient had enlarged lateral nodes.

RESULTS

A total of 43 patients were enrolled. Grade 3-4 adverse events occurred in nine patients during induction chemotherapy and in five patients during chemoradiotherapy. One patient declined surgery with a clinical complete response. Forty-two patients underwent surgery, and 16 had pCR [37.2%, 95% confidence interval (CI) 24.4-52.1%]. All underwent R0 resection without conversion, including combined resection of adjacent structures (n = 14) and lateral node dissection (n = 30). Clavien-Dindo grade 3-4 complications occurred in six patients (14.3%). With median follow-up of 52 months, six developed recurrences (lung n = 5, local n = 1; 3-year relapse-free survival 86.0%).

CONCLUSIONS

This study achieved a high pCR rate with favorable toxicity and postoperative complications in poor-risk locally advanced low rectal cancer. Multicenter study is warranted to evaluate this regimen.

Regulation of radiosensitivity by 4-methylumbelliferone via the suppression of interleukin-1 in fibrosarcoma cells

Tumor recurrence and distant metastasis following radiotherapy, which can lead to poor prognosis, are caused by residual cancer cells that acquire radioresistance. Chemotherapy or a combination of targeted inhibitors can potentially enhance radiation sensitivity and prevent metastasis. It was previously reported that co-administration of the hyaluronan synthesis inhibitor 4-methylumbelliferone (4-MU) enhanced the lethality of X-ray irradiation in HT1080 human fibrosarcoma cells and decreased their invasiveness to a greater extent than either treatment alone. To clarify the molecular basis of these effects, the present study conducted mRNA expression profiling by cDNA microarray to identify the signaling pathways that are altered under this combination treatment. The activation state of the signaling pathways was classified by z-scores in the Ingenuity Pathway Analysis. The results revealed that the pro-inflammatory cytokines interleukin (IL)-6 and IL-8 were activated by 2 Gy X-ray irradiation, an effect that was abolished by co-administration of 4-MU. Similar trends were observed for the upstream signaling component IL-1. These results indicate that the radiosensitivity of fibrosarcoma cells is improved by suppressing inflammation through the administration of 4-MU.

A New N Staging System for Colorectal Cancer in the Era of Extended Lymphadenectomy

BACKGROUND

Complete mesocolic excision is becoming popular in colon cancer surgery in Western countries, and in the tumor-node-metastasis (TNM) classification of rectal cancer, a part of the lateral pelvic lymph nodes is classified as regional. However, the appropriateness of TNM staging according to the assessment of nodal status exclusively by extended lymphadenectomy remains unclear.

PATIENTS AND METHODS

Using a nationwide multicenter database in Japan, we retrospectively analyzed 6866 patients with stage III colorectal cancer (CRC) treated with extended (D3) dissection. First, the best cutoff values for the number of metastatic nodes were explored. Second, the utility of the metastatic status of the main lymph nodes (i.e., at the origin of the feeding artery) and the lateral pelvic lymph nodes ("jN3" category in the Japanese staging system) as N staging criteria was evaluated. The modified N staging system that had the best risk stratification power was determined according to the Akaike information criterion (AIC).

RESULTS

Excellent performance was noted when the number of metastatic nodes was categorized by cutoff values of "3/4" and "6/7." Categorization of nodal metastasis was proven the most clinically efficacious when classified as modified-N1 (N1 and jN3-negative), modified-N2a (N2a and jN3-negative), and modified-N2b (N2b and/or jN3-positive; AIC, 22,810.8), rather than the classification based on the TNM (AIC, 22,849.2) or Japanese staging system (AIC, 22,811.1).

CONCLUSIONS

We structured a modified N staging system according to the number and extent of lymph node metastases. The modified system may be used in stage III cases for precise risk stratification.