Multimodal Management of Retroperitoneal Lymph Node Metastases in Colorectal Cancer: A Single-Center Retrospective Analysis.

[BACKGROUND] Retroperitoneal lymph node metastases (RLNMs) of colorectal cancer (CRC) have a low incidence, and the optimal treatment strategy remains unclear due to limited evidence. This study aimed to analyze morbidity and long-term oncologic outcomes associated with different multimodal approaches including systemic chemotherapy, surgery with or without preoperative radiotherapy.

[METHODS] This retrospective, single-center study included consecutive patients treated from 2000 to 2023 for sub-renal RLNM from CRC. After induction chemotherapy, the patients were divided into two groups: those receiving radio(chemo)therapy (RCT) followed by surgery (RCT-surgery group; n = 30) and those undergoing upfront surgery (surgery-alone group; n = 24). The study analyzed treatment methods, perioperative data, morbidity, mortality, overall survival (OS), and recurrence-free survival (RFS).

[RESULTS] The study included 54 patients (32 males, 22 females, age 51 years). Presentation of RLNM was synchronous in 48.1% (n = 25) of the patients, and 25.9% (n = 14) of the patients had previously treated extra-nodal metastases. Standardized retroperitoneal nodal dissection (RND) was performed for 40 (90.7%) patients. Operative time, blood loss, severe postoperative morbidity, and hospital length of stay were similar between the RCT-surgery and surgery-alone groups. Preoperative RCT was associated with a higher rate of complete response (18.2% vs 0%; p = 0.018). The median RFS was 13.1 months for the RCT-surgery group and 8.6 months for the surgery-alone group (p = 0.153). The median OS was 73.9 months for the surgery-alone group and not reached in the RCT-surgery group (p = 0.909).

[CONCLUSION] A multimodal curative strategy combining nodal dissection after systemic chemotherapy with or without preoperative RCT for RLNM from CRC is feasible, demonstrating low morbidity and promising oncologic outcomes in advanced metastatic disease.