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

The diagnosis and oncological outcomes of obturator and internal iliac lymph node metastasis in middle-low rectal cancer: results of a multicenter Lateral Node Collaborative Group study in China

BACKGROUND

Lateral lymph node dissection (LLND) can decrease local recurrence to lateral compartments in middle-low rectal cancer, but pathological evidence for optimal surgical indications, especially after neoadjuvant (chemo)radiotherapy (nCRT), is lacking. This study aimed to identify the predictive factors and oncological outcomes for different LLN locations associated with pathological metastasis.

METHOD

In this multicenter study, patients from 19 centers who underwent total mesorectal excision (TME) with LLND for locally advanced mid-/low rectal cancer from January 2012 to December 2021 were included.

RESULTS

All 566 included patients underwent TME with LLND surgery; 241 (37.4%) of the largest LLNs were located in the obturator area, and 403 (62.6%) of the largest LLNs were located in the internal iliac area. Multivariate analysis revealed that a short-axis size of 9 mm for the obturator area and 6 mm for internal iliac nodes constituted a reliable indicator of pathological LLN metastasis in non-CRT patients. In nCRT patients, a short-axis node size of 7 mm for obturator nodes and 4 mm for internal iliac nodes could be used to accurately predict pathological LLN metastasis. In contrast to pathological internal iliac node metastasis, pathological obturator node metastasis was associated with lower distant metastasis-free survival (DMFS) (P = 0.001), cancer-specific survival (CSS) (P = 0.043), and overall survival (OS) (P = 0.009), but lower lateral local recurrence-free survival (LRFS) (P > 0.05) was not statistically significant.

CONCLUSIONS

The obturator and internal iliac nodes may be two completely different types of LLNs, and the optimal cutoff value for predicting pathological LLN metastasis is inconsistent regardless of nCRT. Clinical trial registration The protocol of the current study was registered on ClinicalTrials.gov (NCT04850027), and the protocols were in accordance with the standards set by the World Medical Association Declaration of Helsinki.

Short-term outcomes of 47 selective laparoscopic lymph node dissection for rectal cancer: A retrospective study

This study aims to analyze the safety, feasibility, and short-term oncology outcomes of selective laparoscope lateral lymph node dissection (LLND) with total mesorectal excision surgery. Between December 2019 and May 2023, LLND with total mesorectal excision surgery was performed in 47 selected patients with advanced rectal cancer. Surgical complications and 2-year oncology survival outcomes were analyzed in the study. All 47 procedures were technically successful without converting conversion to open surgery. The mean operation time was 200.6 minutes (135-321 minutes), and the mean estimated blood loss was 92.9 mL (range 10-2000 mL). The most common postoperative complications were anastomotic (8.5%, n = 4), ileus (6.4%, n = 3), and chyle leakage (4.3%, n = 2). Lateral pelvic lymph node metastases were found in 19 (40.4%) patients. When divided into lateral pelvic lymph node positive and negative groups, there was no significant impact on overall survival (94.4% vs 100%, Log-rank P = .596) and local recurrence-free survival (LFRS) (76.7% vs 89.6%, Log-rank P = .210), except disease-free survival (DFS) (58.3% vs 90.2%, Log-rank P = .005). Subgroup analysis showed similar short-term survival outcomes between the pN+ group and the internal iliac metastasis group (Log-rank P of overall survival, LFRS, and DFS were all ˃.05). LRFS and DFS in the obturator or external iliac metastasis group were worse than those in the internal iliac metastasis group when the follow-up time was extended (Log-rank P of LFRS and DFS were .05 and .063). Selective laparoscopy LLND for rectal cancer is safety and feasibility, and its complications are manageable. Oncology survival outcomes for lateral pelvic lymph node metastases limited to the internal iliac are similar to the pN+ stage; therefore, it should be treated positively.

Primary staging of rectal cancer on MRI: an updated pictorial review with focus on common pitfalls and current controversies

Magnetic resonance imaging (MRI) plays a pivotal role in primary staging of rectal cancer, enabling the determination of appropriate management strategies and prediction of patient outcomes. However, inconsistencies and pitfalls exist in various aspects, including rectal anatomy, MRI protocols and strategies for artifact resolution, as well as in T- and N-staging, all of which limit the diagnostic value of MRI. This narrative and pictorial review offers a comprehensive overview of factors influencing primary staging of rectal cancer and the role of MRI in assessing them. It highlights the significance of the circumferential resection margin and its relationship with the mesorectal fascia, as well as the prognostic role of extramural venous invasion and tumor deposits. Special attention is given to tumors of the lower rectum due to their complex anatomy and the challenges they pose in MRI staging. The review also addresses current controversies in rectal cancer staging and the need for personalized risk stratification. In summary, this review provides valuable insights into the role of MRI in the primary staging of rectal cancer, emphasizing key aspects for accurate assessment to enhance patient outcomes.

Feasibility and limitations of combined treatment for lateral pelvic lymph node metastases in rectal cancer

Colorectal cancer ranks among the most commonly diagnosed cancers globally, and is associated with a high rate of pelvic recurrence after surgery. In efforts to mitigate recurrence, pelvic lymph node dissection (PLND) is commonly advocated as an adjunct to radical surgery. Neoadjuvant chemoradiotherapy (NACRT) is a therapeutic approach employed in managing locally advanced rectal cancer, and has been found to increase the survival rates. Chua et al have proposed a combination of NACRT with selective PLND for addressing lateral pelvic lymph node metastases in rectal cancer patients, with the aim of reducing recurrence and improving survival outcomes. Nevertheless, certain studies have indicated that the addition of PLND to NACRT and total mesorectal excision did not yield a significant reduction in local recurrence rates or improvement in survival. Consequently, meticulous patient selection and perioperative chemotherapy may prove indispensable in ensuring the efficacy of PLND.