Clinical implication of additional selective lateral lymph node excision in patients with locally advanced rectal cancer who underwent preoperative chemoradiotherapy

To identify the indication and prognostic significance of lateral lymph node (LLN) excision in locally advanced rectal cancer patients underwent preoperative chemoradiotherapy. Included were 67 consecutive patients with suspicious LLN metastasis who underwent chemoradiotherapy and surgery including selective LLN excision (82 excisions). The excisions were grouped according to the presence of LLN metastasis and compared in terms of the clinicopathological findings and oncological results. The correlation between the largest short-axis diameter of LLN measured by imaging and metastasis rates was explored. LLN metastases were identified in 32 excisions (40.0 %). The calculated short-axis LLN diameter predicting metastasis was 11.7 mm (before chemoradiotherapy) and 11.4 mm (before surgery). LLN metastasis was observed more frequently in the low rectum (p = 0.031) and associated with higher CEA levels (p = 0.048). The 3-year overall survival rates for patients with and without LLN metastasis were 60.3 % and 90.3 % (p = 0.048), while the 3-year disease-free survival rates were 31.4 % and 70.5 % (p = 0.009). The hazard ratio of LLN metastasis for recurrence was 2.938 (95 % CI = 1.258-6.863). LLN metastasis in rectal cancer patients underwent chemoradiotherapy was a distinct poor prognostic factor. Selective LLN excision based on imaging studies may have a role for such patients.