Management, treatment and prognostic significance of lateral lymph node metastases in rectal cancer-a regional cohort study

Purpose Lateral lymph node metastases in rectal cancer remain a clinical challenge. Different treatment regimens have been suggested. This retrospective regional cohort study examines outcome after combined oncological and surgical treatment of MRI-positive lateral lymph nodes (LLN). Methods Data from the Swedish Colorectal Cancer Registry (SCRCR) and patient records were used for retrospective analysis of resected high-risk rectal cancers between 2009 and 2014. The aim was to compare tumour characteristics, neoadjuvant therapy, recurrence and outcome after lateral lymph node dissection. Results One thousand and one hundred nineteen cases were identified and after exclusion 344 patients with cT3-T4 <= 10 cm from the anal verge were analysed. Thirty (8.7%) patients with MRI-positive LLN were identified. Synchronous distant metastases were associated with MRI-positive LLN (p-value 0.019). Long-course chemoradiotherapy was clinical practice in cases of MRI-positive LLN. No differences in local (p-value 0.154) or distant (p-value 0.343) recurrence rates between MRI-positive LLN patients and MRI-negative patients were detected. Only four patients underwent lateral lymph node dissection (LLND). There was no significant difference in overall survival during follow-up between the MRI-negative (CI at 95%; 99-109 months) and MRI-positive group (CI at 95%; 69-108 months; p-value 0.14). Conclusion Lateral lymph node metastases present a challenging clinical situation. The present study shows that combination of neoadjuvant therapy and selective LLND is an applicable strategy in cases of MRI-positive LLN.

Automated summary

Lateral lymph node metastases in rectal cancer pose a clinical challenge. This study found that synchronous distant metastases were associated with MRI-positive LLN, but there were no significant differences in recurrence rates between patients with MRI-positive and MRI-negative LLN. Long-course chemoradiotherapy was a standard practice in cases of MRI-positive LLN.