Who Should Get Lateral Pelvic Lymph Node Dissection After Neoadjuvant Chemoradiation?

Area of Science:

• Oncology
• Surgical Oncology
• Rectal Cancer Research

Background:

• Lateral pelvic lymph node recurrence remains a significant challenge in rectal cancer management, even with neoadjuvant chemoradiation and total mesorectal excision.
• Identifying appropriate candidates for lateral pelvic lymph node dissection (LPLND) is crucial for optimizing treatment strategies and patient outcomes.

Purpose of the Study:

• To establish clear indications for LPLND in rectal cancer patients following neoadjuvant chemoradiation.
• To correlate imaging-based lymph node size with pathological positivity and recurrence rates.

Main Methods:

• Retrospective analysis of a prospectively collected institutional database from a tertiary care cancer center (2006-2017).
• Inclusion criteria: Rectal cancer patients with suspected lateral pelvic lymph node metastasis undergoing total mesorectal excision with LPLND.
• Primary outcome: Pathologic lateral pelvic lymph node positivity; evaluated associations between pre- and post-treatment lymph node size and recurrence.

Main Results:

• 64 patients were analyzed; mean lateral pelvic lymph node size decreased from 12.6 mm to 8.5 mm post-neoadjuvant chemoradiation.
• A post-treatment size of ≥5 mm was associated with a 64.7% rate of pathological positivity, while <5 mm nodes were all pathologically negative.
• No lateral compartment recurrences were observed in patients who underwent LPLND, particularly in the <5 mm group, with improved survival trends in pathologically negative nodes.

Conclusions:

• Post-neoadjuvant chemoradiation lateral pelvic lymph node size ≥5 mm is a strong predictor of pathological positivity.
• Patients with <5 mm nodes post-treatment did not have positive lymph nodes, suggesting they may not require dissection.
• LPLND should be considered for patients with clinically suspected lateral pelvic lymph node metastasis and post-treatment node size ≥5 mm to prevent recurrence.