Lymph Node Metastasis in Extraperitoneal Rectal Cancer After Neoadjuvant Therapy: An Unsolved Problem?

Area of Science:

• Oncology
• Surgical Oncology
• Gastroenterology

Background:

• Growing interest in organ-sparing approaches like transanal local excision and watch-and-wait for locally advanced rectal cancer post-neoadjuvant chemoradiotherapy (nCRT).
• Complete lymph nodal response (pN0) is a mandatory criterion for organ-sparing surgery.
• Current radiological methods have limited specificity in accurately staging lymph node involvement, posing a challenge for conservative treatment selection.

Purpose of the Study:

• To determine the actual percentage of patients eligible for conservative surgery after nCRT.
• To identify predictive factors for lymph node response in rectal cancer patients.

Main Methods:

• Retrospective analysis of 59 rectal cancer patients treated with nCRT followed by total mesorectal excision.
• Exclusion of patients with metastatic disease or those treated with upfront surgery.
• Primary endpoint: pathological lymph nodal response (pN0) rate; Secondary endpoint: identification of predictive factors for lymph node response.

Main Results:

• 62.71% of patients achieved a pN0 status, indicating eligibility for organ-sparing approaches.
• 37.28% of patients had lymph node involvement (pN+), making organ-sparing surgery oncologically unsafe.
• Lower tumor size (T0-T2) and lower tumor grade (
• Higher lymph node ratio, higher pathological stage, and pN+ status were linked to poorer disease-free survival.

Conclusions:

• Organ-sparing approaches are a viable option for select rectal cancer patients with a complete response to nCRT.
• Accurate assessment of lymph node status is critical to avoid understaging and ensure oncological safety.
• Total mesorectal excision remains the preferred approach for advanced rectal tumors, even after nCRT.