Incidence and prognostic significance of lateral lymph node metastasis in patients with advanced low rectal cancer

Post-hoc analysis of clinicopathological factors affecting lateral lymph node metastasis based on STELLAR study for rectal cancer

PURPOSE

In post-hoc analyses of phaseIII randomized controlled study(STELLAR), to analyzethe prognostic impact oflateral pelvic lymph node (LPLN)metastasis in locally advanced rectal cancer (LARC).

METHODS

LPLN metastasis was defined as a short diameter > 7 mm on magnetic resonance imaging (MRI).The studyincluded 591 patients with LARC.All patients received neoadjuvant (chemo)radiotherapy combined withradical resection.

RESULTS

Among 591 patients, 99 (16.8 %) were diagnosed with LPLN metastasis, mostly with unilateral metastasis (79.8 %), with internal iliac lymph node metastasis being more common (81.8 %).Significant differences were found among with and without LPLN metastasis in rectal segmentation (P=0.001),N disease (P<0.001), mesenteric LN metastasis or not (P=0.030). The median follow-up timewas 34.0 months, three-year disease-free survival (DFS),overall survival (OS), andmetastasis-free survival (MFS)were significantly lower in LPLN metastaticgroup than those in LPLN non-metastaticgroup (51.4 % vs. 68.2 %, P<0.001; 71.8 % vs. 84.2 %, P=0.006; 60.8 % vs. 80.1 %,P<0.001), respectively; while there were no significant differences in locoregional recurrence(11.4 % vs. 8.5 %, P=0.564). Multivariate analysis found that LPLN metastasis was an independent prognostic factor affecting DFS (P=0.005), OS (P=0.036),MFS (P=0.001).No significantly survival benefit was observed for the short-term radiotherapy based total neoadjuvant therapy compared to long-term concurrent chemoradiotherapy.

CONCLUSIONS

LPLN metastasis observed byMRI should be considered in LARC patients, especially in populations with lowrectal cancer, N2 disease, and mesenteric LN metastasis. LPLN metastasis diagnosed by MRI is a significant and independent risk factor and is associated with worse DFS, OS, MFS.

Postoperative Morbidity and Factors Predicting the Development of Lymphoceles Following Lateral Pelvic Node Dissection for Rectal Cancer: A Cohort Study

PURPOSE

Lateral pelvic node dissection (LPLND) is indicated in the surgical management of clinically significant pelvic lymphadenopathy associated with rectal malignancies. However, procedure-related morbidity, including the incidence and predisposing factors for lymphoceles arising in this setting have not been adequately evaluated.

METHODS

This retrospective single-institution study included 183 patients with nonmetastatic, lateral node-positive rectal cancer undergoing total mesorectal excision with LPLND between June 2014 and May 2023 to determine the incidence and severity of postoperative complications using the Clavien-Dindo system, with logistic regression performed to model a relationship between lymphocele-development and potentially-predictive variables.

RESULTS

In this cohort, mean age was 45.3 ± 12.81 years, 62.8% were male, and 27.9% had body mass index ≥ 25 kg/m2. Median tumor-distance from the verge was 3.0 (interquartile range [IQR] 1.0-5.0) cm. Following radiotherapy in 86.9%, all patients underwent surgery: 30.1% had open resection and 26.2% had bilateral LPLND. Median nodal-yield was 6 (IQR 4-8) per side. Postoperatively, 45.3% developed complications, with 18% considered clinically significant. Lymphoceles, detected in 21.3%, comprised the single-most common sequelae following LPLND, 46.2% arising within 30 days of surgery and 33.3% requiring intervention. On multivariate analyses, obesity (hazard ratio [HR] 2.496; 95% confidence interval [CI] 1.094-5.695), receipt of preoperative radiation (HR 10.026; 95% CI 1.225-82.027), open surgical approach (HR 2.779; 95% CI 1.202-6.425), and number of harvested nodes (HR 1.105; 95% CI 1.026-1.190) were significantly associated with lymphocele-development.

CONCLUSIONS

Pelvic lymphoceles and its attendant complications represent the most commonly encountered morbidity following LPLND for rectal cancer, with obesity, neoadjuvant radiotherapy, open surgery, and higher nodal-yield predisposing to their development.

Lateral lymph node metastasis without mesenteric lymph node involvement in middle-low rectal cancer: Results of a multicentre lateral node collaborative group study in China

BACKGROUND

Characteristics and prognoses of lateral lymph node (LLN) metastasis but not mesenteric lymph node (LN) metastasis are poorly understood. This study explored patterns of mesenteric and LLN metastases in rectal cancer patients.

METHOD

This retrospective, multicentre study was conducted at three institutions and included patients who underwent total mesorectal excision (TME) with lateral lymph node dissection (LLND) for rectal cancer (n = 271).

RESULTS

Among the patients with LLN metastases, 210 patients (77.5 %) with clinical stage T3-4 disease and 157 patients (57.9 %) with clinical stage N1-N2 disease underwent TME as well as LLND. The prognoses of patients with metastasis confined to LLNs were significantly better than those of patients with both mesenteric and LLN metastases (3-year overall survival: 85.0 % vs. 51.0 %, p = 0.005; 3-year disease-free survival: 75.0 % vs. 26.5 %, p = 0.003) and were similar to those of patients with metastasis confined to mesenteric LNs (3-year overall survival: 85.0 % vs. 83.8 %, p = 0.607; 3-year disease-free survival 75.0 % vs. 68.8 %, p = 0.717). Patients with metastases confined to LLN had a lower proportion of poor histological types (20.0 % vs. 65.3 %, p = 0.002), lymphatic invasion (20.0 % vs. 59.2 %, p = 0.036) and number of LLN metastases (1.6 vs 2.7, p = 0.004), and all metastases were confined to the internal iliac or obturator region (100.0 % vs. 77.6 %, p = 0.008) compared to patients with both mesenteric and LLN metastasis.

CONCLUSIONS

Approximately a quarter of patients with rectal cancer have LLN metastases but no mesenteric LN metastases. These patients have favourable pathological features and prognoses and can be managed and treated for mesenteric LN metastasis.

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.

Lateral pelvic lymph node positivity (LPLNP) score: predictive clinic-radiological model of lateral pelvic lymph node involvement in rectal cancer patients

PURPOSE

The population in Western countries differs significantly from that in Eastern countries, and the prevalence of lateral pelvic lymph node (LPLN) involvement in Western populations remains largely unknown due to the limited application of LPLN dissection (LPLND). This discrepancy is primarily attributed to the higher body mass index commonly observed in Western populations, which increases the risk of intraoperative complications. Consequently, the aim of this study is to describe a specific Western clinico-radiological selection tool for LPLND, namely, the lateral pelvic lymph node positivity (LPLNP) score.

METHODS

This retrospective single center study was designed to elaborate the LPLNP score, which was further tested on a prospective cohort of patients. Clinical and MRI factors associated with LPLN involvement were identified, and logistic regression was used to establish the LPLNP score.

RESULTS

In the retrospective series, 120 patients underwent lateral pelvic lymph node dissection. After stepwise logistic regression, five parameters were ultimately included in the LPLNP score. When tested on 66 prospectively selected patients, 40 with an LPLNP score > 0.23 (corresponding to the highest sensitivity and specificity) underwent LPLND: 22 patients (55%) had pathologically confirmed positive LPLN. The negative predictive value of the LPLNP score was 96%, with a sensitivity of 95.7% and a specificity of 58.1%.

CONCLUSION

The LPLNP score was developed based on the largest group of Western patients with locally advanced rectal cancer. This scoring system demonstrated high sensitivity and specificity during validation on the prospective series, correctly identifying LPLN involvement in 55% of cases.

Cross-sectional investigation of the distribution characteristics and prognostic significance of lateral lymph nodes in patients with rectal cancer

BACKGROUND

Information about the distribution characteristics and prognostic significance of lateral lymph nodes (LLNs) on primary computed tomography (CT) scan in rectal cancer patients is lacking.

METHODS

Between January 2013 and December 2016, patients with pathologically proved rectal cancer and pretreatment abdominal enhanced CT in our department were screened. We firstly redivided LLNs into seven categories based on their locations. Then, the number and distribution of all measurable LLNs and the characteristics of the largest LLN in each lateral compartment were recorded. Furthermore, we investigated the long-term outcomes in patients with different LLN characteristics and LLN risk scoring.

RESULTS

A total of 572 patients were enrolled in this study. About 80% of patients had measurable LLNs, and most patients developed measurable LLNs in the obturator cranial compartment. Lateral local recurrence (LLR) was observed in 20 patients, which accounted for 83.3% of the local recurrence (LR). Patients with the largest LLN short-axis diameter >10 mm had a poor prognosis, which was similar to that in patients with simultaneous distant metastasis (SDM). Patients with LLN risk scoring ≥2 had a worse prognosis than those with LLN risk scoring <2, while better than those with SDM.

CONCLUSION

This study suggests that LLR is the main locoregional recurrence pattern. Most rectal cancer patients have measurable LLNs on primary CT scan. However, patients with enlarged LLNs <10 mm or LLN risk scoring <2 still have a significantly better prognosis than patients with SDM, which indicated the potential value of locoregional treatment for these LLNs.

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.

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.

The Effect of (Chemo)Radiotherapy on Enlarged Lateral Lymph Nodes in Patients With Locally Advanced Rectal Cancer

BACKGROUND

Standard of care for most patients with locally advanced rectal cancer in The Netherlands consists of neoadjuvant chemoradiotherapy (nCRT) followed by resection. Enlarged lateral lymph nodes (LLNs), especially in the iliac compartment, appears to be associated with an increased risk of local recurrence. Little is known about the risk of local recurrence after nCRT.

MATERIALS AND METHODS

This study included patients with locally advanced rectal cancer and enlarged LLNs on pretreatment MRI-scan located in the internal iliac, obturator, external iliac, or common iliac compartment. Patients were treated with nCRT and response to therapy was evaluated with MRI-scan. The primary endpoint was local lateral recurrence after nCRT. Secondary endpoints included overall survival and postoperative complications.

RESULTS

Out of 260 patients treated for rectal cancer, a total of 46 patients with enlarged LLNs (18% of all patients) were included between 2012 and 2019 in 2 Dutch hospitals. No patients had lateral lymph node recurrence (LLNR) after nCRT. Only 1 patient had local recurrence of rectal cancer after radical resection during a median follow up of 3 years. Disseminated disease was seen in 12 patients and 9 patients died during follow-up, which result in an overall survival rate of 80.4%. Postoperative complications were seen in 41% of patients. There was no 90-days postoperative mortality.

CONCLUSION

Enlarged LLNs are rare after nCRT and no LLNR was found after nCRT in our study population. This could suggest that nCRT only with or without an extra radiotherapeutic boost on enlarged LLNs already reduces the risk of LLNR.

The use of indocyanine green for lateral lymph node dissection in rectal cancer-preliminary data from an emerging procedure: a systematic review of the literature

INTRODUCTION

Lateral lymph node dissection (LLND) for rectal cancer is still not a widely established technique owing to the existing controversy between Eastern and Western countries and the lack of well-designed studies. The risk of complications and the paucity of long-term oncological results are significant drawbacks for further applying this technique. The use of indocyanine green (ICG) near-infrared (NIR) fluorescence for LLND appears as a promising technique for enhancing postoperative and oncological outcomes. This review aims to evaluate the emerging role of ICG during LLND and present the benefits of its application.

MATERIALS AND METHODS

Systematic electronic research was conducted in PubMed and Google Scholar using a combination of medical subject headings (MeSH). Studies presenting the use of ICG during LLND, especially in terms of harvested lymph nodes, were included and reviewed. Studies comparing LLND with ICG (LLND + ICG) or without ICG (LLND-alone) were further analyzed for the number of lymph nodes and postoperative outcomes.

RESULTS

In total, 13 studies were found eligible and analyzed for different parameters. LLND + ICG is associated with significantly increased number of harvested lateral lymph nodes (p < 0.05), minor blood loss, decreased operative time, and probably decreased urinary retention postoperatively compared with LLND-alone.

CONCLUSIONS

The use of ICG fluorescence during LLND is a safe and feasible technique for balancing postoperative outcomes and the number of harvested lymph nodes. Well-designed studies with long-term results are required to elucidate the oncological benefits and establish this promising technique.

Comparison of the short-term surgical outcomes of lateral lymph node dissection for low rectal cancer using a robotic-assisted transabdominal approach alone or supported by a transanal approach

BACKGROUND

Lateral lymph node metastases are a major cause of local recurrence after surgery for advanced low rectal cancer. Lateral lymph node dissection (LLND) may reduce the risk of local recurrence in patients with suspected lateral lymph node metastasis. Recent reports have shown that robotic-assisted LLND can help to reduce the postoperative complication rate, such as urinary disturbance. Furthermore, with the advent of transanal total mesorectal excision, a novel LLND procedure that combines a transabdominal approach with a transanal approach has been reported. This study aimed to clarify the safety and feasibility of robotic-assisted LLND supported by a transanal approach for advanced low rectal cancer.

METHODS

Thirty-nine patients diagnosed to have low rectal cancer between June 2019 and May 2023 were retrospectively enrolled and divided according to whether they underwent LLND via a robotic-assisted transabdominal approach alone (transabdominal group, n = 19) or in combination with a transanal approach (2team group, n = 20). The patient characteristics and short-term surgical outcomes were compared between the two groups.

RESULTS

The total operation time was significantly shorter in the 2team group than in the transabdominal group (366 min vs. 513 min, P < 0.001), as was the time taken to perform unilateral LLND (64 min vs. 114 min, P < 0.001). Furthermore, there was significantly less intraoperative bleeding in the 2team group (30 mL vs. 80 mL, P = 0.004). There was no significant between-group difference in postoperative complications. The incidence of postoperative urinary disturbance was satisfactory at 5% in both groups.

CONCLUSIONS

The operation time for LLND performed by a robotic-assisted transabdominal approach was shortened when supported by a transanal approach. The frequency of postoperative urinary disturbance was low in both groups. Therefore, robotic-assisted abdominal LLND supported by a transanal approach can be considered a promising treatment option for advanced low rectal cancer.

Prediction model of the risk for lateral local recurrence in locally advanced rectal cancer without enlarged lateral lymph nodes: Lessons from a Japanese multicenter pooled analysis of 812 patients

Aim

Although the oncological impact of lateral lymph node dissection on enlarged lateral lymph nodes has been gradually accepted over the last decade, that on lateral lymph nodes without swelling remains doubtful. This study aimed to develop a prediction model for the future risk of lateral local recurrence and to clarify the value of adding lateral lymph node dissection in locally advanced rectal cancer without enlarged lateral lymph nodes.

Methods

This retrospective, multi-institutional study recruited 812 patients with cStage II/III low rectal cancer without enlarged lateral lymph nodes <7 mm. Total lateral local recurrence was a hypothetical value of future risk of lateral local recurrence when lateral lymph node dissection was never performed.

Results

Overall, total lateral local recurrences were observed in 67 patients (8.3%). In the multivariate analyses, the strongest risk factor for total local recurrences was no preoperative chemoradiotherapy (odds ratio [OR][95%Cl]: 33.2 [4.56-241.7], P < 0.001), followed by tumor distance ≤40 mm (OR [95%Cl]: 2.71 [1.51-4.86], P < 0.001) and lateral lymph node 5-7 mm (OR[95%Cl]: 2.38 [1.26-4.48], P = 0.007). In patients with lateral lymph nodes of 5-7 mm, the total lateral recurrence rate was 4.8% after preoperative chemoradiotherapy. Lateral lymph node dissection could reduce from a total lateral local recurrence of 21.6% to an actual lateral local recurrence of 8.0% in patients without preoperative treatment.

Conclusion

We introduce a novel prediction model of future risk of lateral local recurrences, which has the potential to enable us to indicate lateral lymph node dissection selectively according to the patients' risks.

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.

Late Local Recurrence after Neoadjuvant Therapy and Radical Resection for Locally Advanced Rectal Cancer

Neoadjuvant radiochemotherapy (RCT) and lately total neoadjuvant therapy (TNT) improved local recurrence rates of rectal cancer significantly compared to total mesorectal excision (TME) alone. Yet the occurrence and impact of late local recurrences after many years appears to be a distinct biological problem. We included n = 188 patients with rectal cancer after RCT and radical resection in this study; n = 38 of which had recurrent disease (sites: local (8.0%), liver (6.4%), lung (3.7%)). We found that 68% of all recurrences developed within the first two years. Four patients, however, experience recurrence >8 years after surgery. Here, we report and characterize four cases of late local recurrence (10% of patients with recurrent disease), suggesting that neoadjuvant therapy in principle delays local recurrence.

Total Mesorectal Excision with or without Lateral Pelvic Lymph Node Dissection in Rectal Cancer

Results

Incidence of local recurrence was slightly higher in Group A (8.7%) than in Group B (4.3%) but was not statistically significant. There was no statistical significance between both groups regarding distant metastasis (8.7% in Group A and 13% in Group B). Urinary and sexual dysfunctions were higher in Group B (26.1%) compared to those in Group A (21.7%) but were not statistically significant. The incidence of lateral pelvic lymph node metastasis was 30.4%. Also, intraoperative blood loss was higher and operative time was longer in Group B which was statistically significant (P value <0.001).

Conclusion

Our conclusion was that prophylactic addition of LPLD to TME was not associated with a statistically significant decrease in the risk of local recurrence or distant metastasis in patients with rectal cancer, although it was numerically better. LPLD is associated with longer operative time and higher intraoperative blood loss.

Low Rectal Cancers at Initial Staging MRI

Low rectal cancers, which are associated with increased risk of local recurrent disease and poorer prognosis, have unique anatomic considerations and issues for staging and treatment that do not apply to mid and high rectal cancers. Although tumor histology help drive the staging and treatment of all rectal cancers, it is of particular importance in low rectal cancers, which may involve the anal canal, to help establish whether a low rectal mass should be staged and treated as a rectal cancer (ie, adenocarcinoma) or an anal cancer (ie, squamous cell carcinoma). Optimal staging and treatment of rectal cancer are contingent on tumor location and local extent, which help guide management decisions including neoadjuvant therapy and curative surgical treatment strategies. Tumor location in the low rectum and local involvement of the anal canal, sphincter, and pelvic floor help determine whether a patient can undergo sphincter-preserving resection such as a low anterior resection versus abdominoperineal resection to achieve negative surgical margins. Issues exist related to the anatomy and patterns of disease spread that are unique to the low rectum and include how to determine and stage anal sphincter involvement, mesorectal fascia status at the pelvic floor, and nodal status of extramesorectal nodes such as the external iliac and inguinal lymph nodes. For these reasons, it is imperative that radiologists who interpret rectal cancer staging MRI examinations feel comfortable with the unique anatomy of the low rectum and anal canal, nuances of low rectal cancer local disease spread, and treatment paradigms for low rectal cancer. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center. See the invited commentary by Gollub in this issue.

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.

Global Status of Research on Lateral Lymph Nodes in Rectal Cancer from 1994 to 2022: A Bibliometric Analysis

Tremendous progress has been made in the field of lateral lymph nodes (LLNs) in rectal cancer, but no bibliometric analysis in this field has been carried out and published. To reveal the current status and trends in LLNs in rectal cancer, this bibliometric analysis was performed. Cooperation network, co-citation and keyword co-occurrence analyses were conducted. Annual publication, cooperation relationships among authors, institutions and countries, co-cited journal, co-cited author, co-cited reference and keywords were the main outcomes. A total of 345 studies were included in this bibliometric analysis. The number of articles published in this field has been increasing year by year. The authors, institutions and countries worked closely together in this field. Japan has the largest number of published articles, accounting for 51.59% of the total publications. International Journal of Colorectal Disease (30 papers, 8.70%) published the most papers in this field. The JCOG0212 trial was the most cited article. Preoperative chemoradiotherapy, multicenter, lateral lymph node dissection (LLND) and metastasis are recent hot keywords, and LLND had the highest burst strength. In conclusion, this bibliometric analysis found that Japanese institutions and authors dominated the field of LLNs in rectal cancer. The JCOG0212 trial was the most influential article, which had a significant impact on the development of guidelines. LLND is a hotspot in this field with the highest burst strength. Further prospective studies are needed in this field.

Total neoadjuvant treatment to increase the clinical complete response rate for distal locally advanced rectal cancer (TESS): A study protocol of a prospective, open-label, multicenter, single-arm, phase 2 trial

BACKGROUND

Standard treatment of locally advanced rectal cancer (LARC) was neoadjuvant chemoradiotherapy (CRT), followed by total mesorectal excision (TME). Total neoadjuvant treatment (TNT), a new concept, attempts to deliver both systemic chemotherapy and neoadjuvant CRT prior to surgery. Patients treated with neoadjuvant chemotherapy were more likely to show higher tumor regression. The objective of this trial was to increase complete clinical rate (cCR) for LARC patients by optimizing tumor response, using TNT regimen as compared to conventional chemoradiotherapy. TESS, a prospective, open-label, multicenter, single-arm, phase 2 study, is underway.

METHODS

Main inclusion criteria include cT3-4aNany or cT1-4aN+ rectal adenocarcinoma aged 18-70y; Eastern Cooperative Oncology Group (ECOG) performance 0-1; location ≤5 cm from anal verge. Ninety-eight patients will receive 2 cycles of neoadjuvant chemotherapy Capeox (capecitabine + oxaliplatin) before, during, and after radiotherapy 50Gy/25 fractions, before TME (or other treatment decisions, such as Watch and Wait strategy) and adjuvant chemotherapy capecitabine 2 cycles. Primary endpoint is the cCR rate. Secondary endpoints include ratio of sphincter preservation strategy; pathological complete response rate and tumor regression grade distribution; local recurrence or metastasis; disease-free survival; locoregional recurrence-free survival; acute toxicity; surgical complications; long-term anal function; late toxicity; adverse effect, ECOG standard score, and quality of life. Adverse events are graded per Common Terminology Criteria for Adverse Events V5.0. Acute toxicity will be monitored during antitumor treatment, and late toxicity will be monitored for 3 years from the end of the first course of antitumor treatment.

DISCUSSION

The TESS trial aims to explore a new TNT strategy, which is expected to increase the rate of cCR and sphincter preservation rate. This study will provide new options and evidence for a new sandwich TNT strategy in patients with distal LARC.

Transanal lateral lymph node dissection with intraoperative hologram support in low rectal cancer

BACKGROUND

In Japan, the standard treatment for stage II/III advanced low rectal cancer is total mesorectal excision plus lateral lymph node dissection (LLND). There are also recent reports on the use of transanal LLND. However, the transanal anatomy is difficult to understand, and additional support tools are required to improve the surgical safety. The present study examined the utility of holograms with mixed reality as an intraoperative support tool for assessing the complex pelvic anatomy.

METHODS

Polygon (stereolithography) files of patients' pelvic organs were created and exported from the SYNAPSE VINCENT imaging system and uploaded into the Holoeyes MD virtual reality software. Three-dimensional images were automatically converted into patient-specific holograms. Each hologram was then installed into a head mount display (HoloLens2), and the surgeons and assistants wore the HoloLens2 when they performed transanal LLND. Twelve digestive surgeons with prior practice in hologram manipulation evaluated the utility of the intraoperative hologram support by means of a questionnaire.

RESULTS

Intraoperative hologram support improved the surgical understanding of the lateral lymph node region anatomy. In the questionnaire, 75% of the surgeons answered that the hologram accurately reflected the anatomy, and 92% of the surgeons answered that the anatomy was better understood by simulating the hologram intraoperatively than preoperatively. Moreover, 92% of the surgeons agreed that intraoperative holograms were a useful support tool for improving the surgical safety.

CONCLUSIONS

Intraoperative hologram support improved the surgical understanding of the pelvic anatomy for transanal LLND. Intraoperative holograms may represent a next-generation surgical tool for transanal LLND.

Robot-assisted lateral pelvic lymph node dissection in patients with advanced rectal cancer: a single-center experience of 65 cases

The treatment of lateral pelvic lymph node (LPLN) metastasis of rectal cancer has evolved because of technical difficulties from open surgery to laparoscopy and, recently, robot-assisted surgery. This study aimed to evaluate the technical feasibility and short- and long-term outcomes of robot-assisted LPLN dissection (LPND) following total mesorectal excision (TME) in advanced rectal cancer. Clinical data of 65 patients who underwent robotic-assisted TME with LPND from April 2014 to July 2022 were reviewed. Data regarding operative details, postoperative morbidity (within 90 postoperative days) for short-term outcomes and lateral recurrence as long-term outcomes were analyzed. Among the 65 patients with LPND, preoperative chemoradiotherapy was performed in 49 (75.4%). The mean operative time was 306.8 (range 191-477) min, and the mean time of unilateral LPND was 38.6 (range 16-66) min. LPND was bilaterally performed in 19 (29.2%) patients. The mean number of each side of harvested LPLNs was 6.8. Lymph node metastasis was observed in 15 (23.0%) patients, and 10 (15.4%) patients had postoperative complications. Lymphocele (n = 3) and pelvic abscess (n = 3) were the most common, followed by voiding difficulty, erectile dysfunction, obturator neuropathy, and sciatic neuropathy (all n = 1). During the 25 months of median follow-up, no lateral recurrence of the LPND site was noted. Robot-assisted LPND following TME is safe and feasible and showed acceptable short- and long-term outcomes. Despite some study limitations, we may be able to apply this strategy more widely through subsequent prospective controlled studies.

Transanally assisted lateral pelvic lymph node dissection for rectal cancer

BACKGROUND

Although lateral pelvic lymph node dissection (LLND) might be an effective approach for patients with rectal cancer with lateral lymph node metastasis, it is technically challenging because of the anatomical complexity and location of the deep pelvis. An assistance by transanal approach might be useful for a successful LLND.

METHODS

From September 2016 to May 2021, 39 patients with low rectal cancer underwent transanal total mesorectal excision with LLND. Among them, 18 patients underwent LLND using a conventional laparoscopic approach alone, while the remaining 21 underwent LLND using both conventional and transanal approaches. Their clinical outcomes were retrospectively compared.

RESULTS

The operation time for LLND on each side was significantly shorter in the transanal group (105 min vs. 54 min, P < 0.001). The intraoperative blood loss was also significantly less in the transanal group (40 g vs. 0 g, P = 0.031). The rate of overall postoperative complications ≥ grade II according to the Clavien-Dindo classification was significantly less in the transanal group (66.7% vs. 28.6%, odds ratio: 5.000, 95% confidence intervals: 1.313-19.047, P = 0.040). The number of harvested lateral lymph nodes in both groups was similar (8.5 vs. 8, P = 0.544).

CONCLUSION

The transanal approach for LLND reduced operative time, blood loss, and morbidity compared with the conventional approach alone in a cohort of patients with rectal cancer.

Reappraisal of the Lymphatic Drainage System of the Distal Rectum: Functional Lymphatic Flow into the Presacral Space and Its Clinical Implication in Rectal Cancer Treatment

Understanding the source and route of pelvic metastasis is essential to developing an optimal strategy for controlling local and systemic diseases of rectal cancer. This study aims to delineate the distribution of lymphatic channels and flow from the distal rectum. In fresh-frozen cadaveric hemipelvis specimens, the ligamentous attachment of the distal rectum to the pelvic floor muscles and the presacral fascia were evaluated. Using indocyanine green (ICG) fluorescence imaging, we simultaneously evaluated the gross anatomy of the lymphatic communication of the distal rectum. We also investigated the lymphatic flow in the pelvic cavity intraoperatively in rectal cancer patients who underwent radical rectal resection with total mesorectal excision (TME). In fresh cadavers, multiple small perforating lymphovascular branches exist in the retrorectal space, posteriorly connecting the mesorectum to the presacral fascia. The lymphatic flow from the distal rectum drains directly into the presacral space through the branches. In patients who underwent TME for rectal cancer, intraoperative ICG fluorescence signals were seen in the pelvic sidewalls and the presacral space. This anatomical study demonstrated that the lymphatic flow from the distal rectum runs directly to the pelvic lateral sidewalls and the presacral space, suggesting a possible route of metastasis in distal rectal cancer.

Can patients with good tumor regression grading after neoadjuvant chemoradiotherapy be exempted from lateral lymph node dissection?

OBJECTIVE

To investigate whether lateral lymph node (LLN) dissection (LLND) can be exempted in patients with good tumor regression grading (TRG) after neoadjuvant chemoradiotherapy (nCRT)?

METHODS

A retrospective study was conducted on consecutive patients with advanced rectal cancer who underwent nCRT and total mesorectal resection plus selective LLND at our institution. The primary outcomes are the relationship between LLN metastasis (LLNM) and magnetic resonance imaging TRG (mrTRG) and the relationship between LLNM and pathological TRG (pTRG).

RESULTS

A total of 91 patients were included, of which 24 patients (26.4%) had LLNM, 67 patients (73.6%) had no LLNM. There were significant differences of the maximum short-axis of LLN before and after nCRT, short-axis reduction rate of the LLN with maximum short-axis, length diameter reduction rate of primary tumor, mrTRG, and pTRG between the two groups. Multivariate logistic regression showed that mrTRG (P = 0.026) and pTRG (P = 0.013) were independent predictors for LLNM. The combination used by mrTRG and the maximum short-axis of LLNs ≥ 8 mm before nCRT and the maximum short-axis of LLN ≥ 5 mm after nCRT achieved specificity of 0.970, positive predictive value (PPV) of 0.867, and negative predictive value (NPV) of 0.855. The same combination used by pTRG achieved the specificity of 0.970, PPV of 0.857 and NPV of 0.844.

CONCLUSION

The suspected positive LLNs tend to be sterilized by nCRT in patients who have a very good response to nCRT. It is rational to avoid LLND in patients whose primary tumor and LLNs both show good response to nCRT.

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.

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.

Risk factors and prognostic significance of postoperative complications following lateral pelvic lymph node dissection for rectal cancer: results of the multicenter lateral node study in China

OBJECTIVE

Total mesorectal excision (TME) plus lateral pelvic lymph node (LPN) dissection (LPND) is a technically complex and challenging procedure with higher morbidity than TME alone. We aimed to investigate the risk factors for postoperative complications after TME + LPND, and the impact of complications on patient prognosis.

METHODS

A total of 387 rectal cancer patients with clinical LPN metastasis (LPNM) who underwent TME + LPND at three institutions affiliated with the Chinese Lateral Node Collaborative Group were included. Logistic regression models were used to identify the risk factors for post-surgical complications, and the log-rank test was used to compare the prognosis. Severe complications were described as grade III-V.

RESULTS

The incidence rates of overall complications and severe complications after TME + LPND were 15.2% (59/387) and 7.8% (30/387), respectively. Multivariate analysis showed that a duration of operation ≥260 min was an independent risk factor for both overall (odds ratio [OR] = 3.03, 95% confidence interval [CI] = 1.57-5.85, P = 0.001) and severe postoperative complications (OR = 2.67, 95% CI = 1.06-6.73, P = 0.037). The development of overall postoperative complications (P = 0.114) and severe postoperative complications (P = 0.298) had no significant impact on the overall survival. However, patients with overall complications (P = 0.015) or severe complications (P = 0.031) with a postoperative hospital stay >30 days had significantly an overall worse survival.

CONCLUSION

A surgical duration of ≥260 min is a significant risk factor for both overall and severe postoperative complications after TME + LPND for middle-low rectal cancer. Furthermore, the development of overall complications or severe complications that require a postoperative hospital stay >30 days significantly worsens the prognosis.

Significant improvement after training in the assessment of lateral compartments and short-axis measurements of lateral lymph nodes in rectal cancer

OBJECTIVES

In patients with rectal cancer, the size and location of lateral lymph nodes (LLNs) are correlated to increased lateral local recurrence rates. Sufficient knowledge and accuracy when measuring these features are therefore essential. The objective of this study was to evaluate the variation in measurements and anatomical classifications of LLNs before and after training.

METHODS

Fifty-three Dutch radiologists examined three rectal MRI scans and completed a questionnaire. Presence, location, size, and suspiciousness of LLNs were reported. This assessment was repeated after a 2-hour online training by the same radiologists with the same three cases plus three additional cases. Three expert radiologists independently evaluated these 6 cases and served as the standard of reference.

RESULTS

Correct identification of the anatomical location improved in case 1 (62 to 77% (p = .077)) and in case 2 (46 to 72% (p = .007)) but decreased in case 3 (92 to 74%, p = .453). Compared to the first three cases, cases 4, 5, and 6 all had a higher initial consensus of 73%, 79%, and 85%, respectively. The mean absolute deviation of the short-axis measurements in cases 1-3 were closer-though not significantly-to the expert reference value after training with reduced ranges and standard deviations. Subjective determination of malignancy had a high consensus rate between participants and experts.

CONCLUSION

Though finding a high consensus rate for determining malignancy of LLNs, variation in short-axis measurements and anatomical location classifications were present and improved after training. Adequate training would support the challenges involved in evaluating LLNs appropriately.

KEY POINTS

• Variation was present in the assessment of the anatomical location and short-axis size of lateral lymph nodes. • In certain cases, the accuracy of short-axis measurements and anatomical location, when compared to an expert reference value, improved after a training session. • Consensus before and after training on whether an LLN was subjectively considered to be suspicious for malignancy was high.

Near-Infrared Imaging Using Indocyanine Green for Laparoscopic Lateral Pelvic Lymph Node Dissection for Clinical Stage II/III Middle-Lower Rectal Cancer: A Propensity Score-Matched Cohort Study

BACKGROUND

The examination of the efficacy of near-infrared imaging using indocyanine green in laparoscopic lateral pelvic lymph node dissection remains insufficient.

OBJECTIVE

The aim of this study was to examine whether near-infrared imaging contributed to an increase in the total number of harvested lateral pelvic lymph nodes in laparoscopic lateral pelvic lymph node dissection.

DESIGN

This was a retrospective, multi-institutional study with propensity score matching.

SETTINGS

We conducted this study within the framework of the Yokohama Clinical Oncology Group in Japan.

PATIENTS

The study population included consecutive patients with middle-low rectal cancer (clinical stage II to III) who underwent laparoscopic lateral pelvic lymph node dissection between January 2013 and February 2018.

MAIN OUTCOME MEASURES

The total number of harvested lateral pelvic lymph nodes was compared in laparoscopic lateral pelvic lymph node dissection with and without near-infrared imaging.

RESULTS

A total of 172 eligible patients were included; 84 of these patients underwent laparoscopic surgery with near-infrared imaging. After propensity score matching, 58 patients were matched in each of the near-infrared and the non-near-infrared groups. The operation time in the near-infrared group was significantly longer than that in the non-near-infrared group (426 vs 369 min), and the amount of intraoperative blood loss in the near-infrared group was significantly smaller than that in the non-near-infrared group (13 vs 110 mL). The total number of harvested lateral pelvic lymph nodes in the near-infrared group was significantly higher than that in the non-near-infrared group (14 vs 9). There were no significant differences in the postoperative complication rates of the 2 groups.

LIMITATIONS

The limitations of the present study include its retrospective design.

CONCLUSIONS

This study revealed that laparoscopic lateral pelvic lymph node dissection combined with near-infrared imaging could increase the total number of harvested lateral pelvic lymph nodes without impairing functional preservation. See Video Abstract at http://links.lww.com/DCR/B800.This study was registered with the Japanese Clinical Trials Registry as UMIN000041372 (http://www.umin.ac.jp/ctr/index.htm).IMÁGENES CASI-INFRARROJAS UTILIZANDO VERDE DE INDOCIANINA EN LA DISECCIÓN LAPAROSCÓPICA DE GANGLIOS LINFÁTICOS PÉLVICOS LATERALES EN CASOS DE CÁNCER DE RECTO MEDIO-INFERIOR DE ESTADIO CLÍNICO II / III: ESTUDIO DE COHORTES CON PUNTUACIÓN DE PROPENSIÓNANTECEDENTES:El examen de la eficacia de las imágenes casi-infrarrojas utilizando le verde de indocianina en la disección laparoscópica de los ganglios linfáticos pélvicos laterales sigue siendo insuficiente.OBJETIVO:El objetivo de este estudio fue examinar si las imágenes casi-infrarrojas contribuyeron a un aumento en el número total de ganglios linfáticos pélvicos laterales recolectados durante su disección laparoscópica.DISEÑO:Estudio retrospectivo, multi-institucional con emparejamiento por puntuación de propensión.AJUSTES:Estudio realizado dentro el marco establecido por el Grupo de Oncología Clínica de Yokohama, Japón.PACIENTES:La población estudiada incluyó pacientes consecutivos con cáncer de recto medio-bajo (estadio clínico II a III) que se sometieron a una disección laparoscópica de los ganglios linfáticos pélvicos laterales entre enero de 2013 y febrero de 2018.PRINCIPALES RESULTADOS MEDIDAS:El número total de ganglios linfáticos pélvicos laterales extraídos se comparó en la disección laparoscópica de ganglios linfáticos pélvicos laterales con y sin imágenes casi-infrarrojas.RESULTADOS:Se incluyeron un total de 172 pacientes elegibles; 84 de estos pacientes se sometieron a cirugía laparoscópica con imágenes casi-infrarrojas. Después del emparejamiento por puntuación de propensión, 58 pacientes fueron emparejados en cada uno de los grupos de luz casi-infrarroja y los sin luz. El tiempo de operación en el grupo de luz casi-infrarroja fue significativamente más largo que en el grupo sin luz (426 frente a 369 min), y la cantidad de pérdida de sangre intraoperatoria en el grupo de luz casi-infrarroja fue significativamente menor que en el grupo sin luz (13 frente a 110 ml). El número total de ganglios linfáticos pélvicos laterales recolectados en el grupo de luz casi-infrarroja fue significativamente mayor que en el grupo sin luz (14 frente a 9). No hubo diferencias significativas en las tasas de complicaciones posoperatorias de los dos grupos.LIMITACIONES:Las limitaciones del presente estudio incluyen su diseño retrospectivo.CONCLUSIONES:Este estudio reveló que la disección laparoscópica de los ganglios linfáticos pélvicos laterales combinada con imágenes casi-infrarrojas podría aumentar el número total de ganglios linfáticos pélvicos laterales recolectados sin afectar la preservación funcional. Consulte Video Resumen en http://links.lww.com/DCR/B800. (Traducción-Dr. Xavier Delgadillo)Este estudio se registró en el Registro de Ensayos Clínicos de Japón como UMIN000041372 (http://www.umin.ac.jp/ctr/index.htm).

Robotic pelvic side-wall dissection and en-bloc excision for locally advanced and recurrent rectal cancer: outcomes on feasibility and safety

BACKGROUND

Global differences exist in managing lateral pelvic nodes in rectal cancer. Recent studies demonstrate improved local recurrence rates in patients undergoing lateral pelvic lymph node dissections (LPND) in addition to total mesorectal excision (TME) for advanced lower rectal cancer. This study aims to report on the safety and feasibility of the robotic approach in patients undergoing pelvic sidewall lymph node dissection or en-bloc sidewall resection for advanced lower rectal cancer.

METHODS

Patients who underwent an elective robotic pelvic sidewall lymph node dissection or en-bloc sidewall resection for locally advanced rectal cancer with suspicious lateral lymph nodes or pelvic side wall involvement between January 2018 and March 2021 were included. Demographic, clinical, perioperative and histopathological variables were recorded and analysed.

RESULTS

Eight patients (3 males) with a mean age of 55 (33-73) years and mean body mass index of 26.3 (20.7-30.0) kg/m² were included. The median operative time and blood loss were 458.75 (360-540) min and 143.75 (100-300) mL, respectively. There were no conversions or intra-operative complications. There were three post-operative complications recorded (two ileus and one anastomotic leak which required an endoscopic washout in theatre and intravenous antibiotics thereafter). Median length of stay was 12.75 (7-23) days. All patients had an R0 resection, and the median lateral pelvic lymph node yield was 9.1 (6-14).

CONCLUSION

This series demonstrates the practicality and the safety of the robotic approach in the introduction of this technique for en-bloc resection or LPND in patients with locally advanced rectal cancer.

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.

TeachMe: a web-based teaching system for annotating abdominal lymph nodes

The detection and characterization of lymph nodes through interpreting abdominal medical images are significant for diagnosing and treating colorectal cancer recurrence. However, interpreting abdominal medical images manually is labor-intensive and time-consuming. The related radiology education has many limitations as well. In this context, we seek to build an extensive collection of abdominal medical images with ground truth labels for lymph nodes recognition research and help junior doctors to train their interpretation skills. Therefore, we develop TeachMe, which is a web-based teaching system for annotating abdominal lymph nodes. The system has a three-level annotation-review workflow to construct an expert database of abdominal lymph nodes and a feedback mechanism helping junior doctors to learn the tricks of interpreting abdominal medical images. TeachMe’s functionalities make itself stand out against other platforms. To validate these functionalities, we invite a medical team from Gastrointestinal Surgery Center, West China Hospital, to participate in the data collection workflow and experience the feedback mechanism. With the help of TeachMe, an expert dataset of abdominal lymph nodes has been created and an automated detection model for abdominal lymph nodes with incredible performances has been proposed. Moreover, through three rounds of practicing via TeachMe, our junior doctors’ interpretation skills have been improved.

Oncologic Status of Obturator Lymph Node Metastases in Locally Advanced Low Rectal Cancer: A Japanese Multi-Institutional Study of 3487 Patients

BACKGROUND

The American Joint Committee on Cancer tumor-node-metastasis staging system for rectal cancer defines lateral pelvic lymph nodes (LPLNs) only in the internal iliac region as regional. However, the Japanese Society for Cancer of the Colon and Rectum (JSCCR) staging system, also considers obturator lymph nodes (LNs) as regional. This retrospective cohort study evaluated the oncologic status of obturator LNs in low rectal cancer.

METHODS

The study identified 3487 patients with pT3-T4 low rectal cancer who had undergone curative resections without preoperative radiotherapy or chemotherapy between 2003 and 2011 in the JSCCR database and divided them into six groups. Overall survival (OS) and recurrence-free survival (RFS) were analyzed by groups.

RESULTS

Histologic LPLN metastases were identified in 8% (279/3487) of all the patients and in 18.2% (279/1530) of the patients who underwent lateral pelvic node dissection. The 5-year OS and RFS rates of the obturator-LPLN group (P = 0.095) were worse than those of the internal-LPLN group (P = 0.075), but the difference was not significant. The OS of the obturator-LPLN group was similar to that of the resectable liver metastasis group (P = 0.731), and the RFS of the obturator-LPLN group was significantly better than that of the other-LPLN group (P = 0.016).

CONCLUSION

The prognosis for obturator LN metastases in low rectal cancer was not significantly worse than for internal iliac LN metastases, defined as regional by the current American Joint Committee on Cancer staging system, and the oncologic status of obturator LNs warrants more studies.

Comparison of postoperative laparoscopic and open total mesorectal excision on lower urinary tract function in men with rectal cancer

OBJECTIVES

This study investigated male voiding dysfunction (VD) or lower urinary tract function in rectal cancer (RC) patients after laparoscopic or open total mesorectal excision with pelvic autonomic nerve preservation (PANP).

METHODS

One hundred and eighty-seven male RC patients admitted between January 2016 and May 2019 were enrolled in this study, 112 of whom underwent laparoscopic total mesorectal excision (LTME) and 75 underwent open total mesorectal excision (OTME). The International Prostatic Symptom Score (IPSS) was compared between the two groups.

RESULTS

The postoperative IPSS in patients with RC was elevated on day 7 and gradually decreased during the first month after surgery. Compared with the OTME group, the IPSS scores decreased less in the LTME group at week 1, and months 1 and 3 postoperatively (6.82 ± 2.13 vs 10.15 ± 3.86, 5.70 ± 2.45 vs 7.21 ± 2.0, and 5.01 ± 2.09 vs 5.75 ± 2.55, respectively; P < 0.05). The VD rate was significantly lower in the LTME group than the OTME group at 1, 2, and 3 weeks postoperatively (21.4% vs 26.8%,13.4% vs 25.3%, and 9.8% vs18.6%, respectively; P < 0.05); however, there was no major difference in the incidence of VD 6 months postoperatively between the two groups (P > 0.05). VD was more frequent in the OTME group than the LTME group 6 months postoperatively, but the difference was not statistically significant (odds ratio = 1.857, 95% CI, 0.964-3.645, P = 0.064).

CONCLUSIONS

LTME may be superior to OTME with respect to PANP of lower urinary tract function in males with RC.

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.

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.

Laparoscopic Lateral Pelvic Lymph Node Dissection for Advanced Lower Rectal Cancer: a Preliminary Vietnamese Study

Background

Lateral pelvic lymph node dissection (LPLD) in rectal cancer has been carried out in several major centers. However, there are still many controversial issues regarding this method such as feasibility, safety, and oncological outcome.

Objective

The aim of this study was to evaluate the short-term outcomes, safety, and feasibility of LPLD.

Methods

This was a retrospective study. A total of 117 patients with lower rectal cancer (clinical stage II/III) below the peritoneal reflection underwent surgery between January 2019 and November 2020 at 108 Military Central Hospital, Hanoi, Vietnam.

Results

Total amount of 25 patients underwent laparoscopic total mesorectal excision (TME) plus LPLD and 92 patients underwent laparoscopic TME without LPLD. The rate of lateral pelvic lymph node metastasis in the LPLD group was 16% (4/25), of which 12% (3/25) were on the left side and 4% (1/25) were on the right side. The rate of intraoperative complications in the LPLD group was significantly higher at 16.0% (4/25) compared with 3.3% (3/92) in the TME only group (p = 0.037). There were no statistically significant differences in the rate of postoperative complications between the two groups (24.0% of patients in the LPLD group compared with 26.1% patients in the no LPLD group, p = 0.832).

Conclusion

Pelvic lymphadenectomy has an important role in the treatment of advanced lower rectal cancer. LPLD is a safe and feasible procedure. However, it is necessary to study a larger number of patients with a longer follow-up period to fully evaluate oncological outcomes.

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.

Open versus laparoscopic lateral lymph node dissection for mid- and low- rectal cancer: a propensity score matching study

BACKGROUND

This study aimed to evaluate the perioperative, pathological and oncological outcomes of open versus laparoscopic total mesorectal excision (TME) plus lateral lymph node dissection (LLND) for mid- and low- rectal cancer using propensity score matching.

METHODS

Between September 2009 and December 2018, consecutive patients who underwent open or laparoscopic TME plus LLND were collected. Based on the propensity score matching analysis, laparoscopic TME plus LLND was compared with open TME plus LLND for the perioperative, pathological, and oncological outcomes.

RESULTS

A total of 77 patients were collected. There were 13 patients who underwent open TME plus LLND (open group) and 64 patients who underwent laparoscopic TME plus LLND (laparoscopic group). After propensity score matching, 13 patients in the open group were matched to 39 patients in the laparoscopic group (1:3). The laparoscopic group had a significantly shorter length of incision (5 cm vs. 20 cm, p < 0.01), less intraoperative blood loss (80 mL vs. 100 mL, p = 0.02), and shorter time to postoperative liquid diet (72 h vs. 96 h, p = 0.05). There were no significant differences in both early and late postoperative complications. The 3-year overall survival was 85.9% in the laparoscopic group and 76.9% in the open group (p = 0.75), respectively. The 3-year disease-free survival was 70.6% in the laparoscopic group and 74.1% in the open group (p = 0.83), respectively.

CONCLUSION

Laparoscopic LLND had comparable oncological outcomes to open LLND. Moreover, laparoscopic LLND had postoperative recovery advantages over open LLND.

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.

The expression of carcinoembryonic antigen mRNA in the lavage of the dissected area of the lateral lymph nodes influences the lateral recurrence of lower rectal cancer

PURPOSE

To determine whether or not migrating cancer cells are present on the surgical plane after lateral lymph node dissection (LLND) for lower rectal cancer and related to lateral recurrence (LR), we evaluated the lavage of LLND areas by reverse-transcription polymerase chain reaction (RT-PCR) to check the expression of CEA mRNA in the residual cancer cells.

METHODS

Thirty patients who underwent curative LLND were enrolled. Lavage was collected after LLND and subjected to RT-PCR to detect CEA mRNA. The median follow-up to check for recurrence was 31.4 months.

RESULTS

CEA mRNA was detected in 9 of the 46 dissected areas. Based on the receiver operating characteristic curves, the cut-off value of PCR was set at 0.025. This cut-off point classified five patients into the high-expression group for CEA mRNA. During follow-up, LR developed in 1 of 40 low-expression areas of CEA mRNA and 3 of 6 high-expression areas. The LR rate was higher in the high-expression group than in the low-expression group (p = 0.015). A multivariate analysis showed that the high expression of CEA mRNA was likely an independent prognostic factor of LR.

CONCLUSION

The expression of CEA mRNA in the lavage of LLND areas indicates the presence of residual cancer cells that cause LR.

Risk factors for surgical site infection and association of surgical site infection with survival of lower rectal cancer patients without clinical lateral pelvic lymph node metastasis (clinical Stage II/III): Analysis of data from JCOG0212

This study aimed to examine the risk factors for surgical site infection (SSI) and the association of that with recurrence in JCOG0212. The results for secondary endpoints showed that compared with the mesorectal excision (ME) alone group, ME with lateral lymph node dissection (LLND) group showed significantly longer operative time and significantly higher blood loss. These results suggested that LLND was a risk factor for SSI. All 701 patients registered in JCOG0212 were analyzed in this study. Wound infection was defined as incisional/deep SSI, and pelvic abscess and anastomotic leakage were defined as organ/space SSI. The risk factors for the incidence of SSI and the effect of SSI on relapse-free survival (RFS) were investigated. Multivariable odds ratio of Grade 2 or higher all SSI was 0.58 [95% Confidence interval: 0.36–0.93] for female (vs. male) and that of Grade 2 or higher incisional/deep SSI was 2.24 [1.03–4.86] for blood infusion. For RFS, patients with Grade 3 or higher all SSI showed poor prognosis (multivariable hazard ratio: 1.66 [1.03–2.68]). LLND is not significant factor for the incidence of all SSI. Male sex might be a risk factor of Grade 2 or higher SSI, and blood transfusion is a possible risk factor of Grade 2 or higher incisional/deep SSI. Grade 3 or higher all SSI might be a significant worse prognostic factor for lower rectal cancer.

No benefit after neoadjuvant chemoradiation in stage IV rectal cancer: A propensity score-matched analysis on a real-world population

BACKGROUND

Stage IV rectal cancer occurs in 25% of patients and locoregional control of primary tumor is usually poorly considered, since priority is the treatment of metastatic disease.

AIMS

This study evaluates impact of neoadjuvant chemoradiation followed by surgery (nCHRTS) vs. upfront surgery on locoregional control and overall survival in stage IV rectal cancer.

METHODS

All patients diagnosed with stage IV rectal carcinoma between 2009 and 2019, undergone elective surgery at the National Cancer Institute of Milan (Italy), were included. Propensity score-based matching was performed between the two study groups. Loco-regional recurrence-free survival (LRRFS) and overall survival (OS) were analysed using Kaplan-Meyer method.

RESULTS

A total of 139 patients were analyzed. After propensity score matching, 88 patients were included in the final analysis. The 3-yr LRRFS rates were 80.3% for nCHRTS vs. 90.4% for upfront surgery patients (p = 0.35). The 3-yr OS rates were respectively 81.8% vs. 58% (p = 0.36). KRAS mutation (HR 2.506, p = 0.038) and extra-liver metastases (HR 4.308, p = 0.003) were both predictive of worse OS in univariate analysis.

CONCLUSION

The present study failed to demonstrate a significant impact of nCHRTS on LRRFS or OS in stage IV rectal cancer.

The Significance of Lateral Lymph Node Metastasis in Low Rectal Cancer: a Propensity Score Matching Study

BACKGROUND

The indications for lateral lymph node dissection (LLND) in rectal cancer have been controversial. The purpose of this study was to clarify the significance of lateral lymph node metastasis in low rectal cancer.

METHODS

This was a retrospective study at a high-volume cancer center in Japan. In this study, 40 patients with pathologically positive LLN (LLN+) were matched with 175 negative (LLN-) patients by propensity score matching (PSM). COX regression analysis was used to identify independent risk factors related to prognosis. The relapse-free survival rate (RFS) and overall survival rate (OS) of the 2 groups before and after matching were analyzed.

RESULTS

Of the 64 patients undergoing LLND, 40 (62.5%) patients had LLN+ disease. The LLN+ patients showed deeper infiltration of the primary tumor than the LLN- patients (T3-T4: 87.5% vs. 72.0%; p = 0.044), a greater number of metastatic lymph nodes (N2: 75.0% vs. 35.4%; p < 0.001), and a higher rate of local recurrence (30% vs. 9.1%; p < 0.001). Adjuvant chemotherapy was more common in the 40 LLN+ patients than in the 175 LLN- patients (70.0% vs. 46.8%; p = 0.008). After relapse, the rate of first-line chemotherapy administration for LLN+ patients was higher than that for the LLN- patients (62.5% vs. 29.5%; p = 0.005). The RFS of LLN+ patients was shorter than that of the LLN- patients (p = 0.005). After PSM, although more LLN+ patients received adjuvant chemotherapy than the LLN- patients (70.0% vs. 40.0%; p = 0.007), the local recurrence rate remained higher (30% vs. 10%; p = 0.025). The differences between RFS (p = 0.655) and OS rates (p = 0.164) of the 2 patient groups were not significant.

CONCLUSION

Even after LLND, patients with LLN+ low rectal cancer still showed an elevated local recurrence rate. Controlling local recurrence by adjuvant chemotherapy alone is difficult, and the additional strategic treatments are needed.