Lateral pelvic lymph node dissection for rectal cancer after neoadjuvant chemoradiotherapy. Results of a prospective study

AIM: to evaluate the early results of selective lateral pelvic lymph node dissection (LPLD) in patients with middle and low rectal cancer after neoadjuvant CRT with suspected lateral lymph nodes (LLN) involvement based on MRI data.

PATIENTS AND METHODS: a prospective single-arm single-center study included 70 patients with a verified diagnosis of rectal cancer (mrT1–4N1–2сM0–1) who underwent total mesorectal excision (TME) with LTLD after neoadjuvant chemotherapy between January 2023 and May 2025. Intraoperatively, all patients underwent fluorescent navigation with indocyanine green and LLN ultrasound. The primary endpoint was the presence of metastases in the LLN based on histology. Secondary endpoints included: sensitivity and specificity of MRI in detecting LLN metastases, postoperative morbidity, local recurrence rate, operation time, blood loss, hospital stay, and the relationship between LLN size and the presence of metastases.

RESULTS: in 23/70 (33%) patients, metastatic involvement of the LLN was confirmed. The sensitivity and specificity of MRI were 91% (95% CI: 72.0%–98.9%) and 38% (95% CI: 24.5%–53.6%). A comparison of the median short axis in patients with metastatic LLN involvement (9.2 (7.8; 11.3) mm) and in patients without metastasis (5.4 (4.2; 6.5) mm) revealed a significant difference (p < 0.001). The operation time was 210 (170; 265) minutes, and total blood loss was 60 (30; 120) ml. Clavien–Dindo grade I-II complications detected in 16/70 (23%) patients. No cases required re-operation. The hospital stay was 12 (10; 16) days. Local recurrences revealed in 3/70 (4%) patients with follow-up of 14 (8; 20) months.

CONCLUSION: selective LPLD after neoadjuvant HLT is a potentially effective method for reducing the risk of local recurrence in patients with suspected LLN involvement in rectal cancer. However, randomised controlled trials with a long follow-up period are needed to definitively assess its contribution to improving late outcomes.

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