Fewer than 12 lymph nodes can be expected in a surgical specimen after high-dose chemoradiation therapy for rectal cancer.

Purpose: Lymph node harvest of >or=12 has been adopted as a marker for adequacy of resection for colorectal cancer. We have noted a paucity of lymph nodes in rectal cancer specimens after neoadjuvant therapy, positing that the number of lymph nodes depends on the response to radiation and may not be an appropriate benchmark. Our purpose was to determine whether the number of lymph nodes harvested after neoadjuvant therapy is a useful quality indicator.

Methods: A database of rectal cancer patients was queried to identify patients undergoing total mesorectal excision after neoadjuvant chemoradiation between January 1997 and August 2007. We compared patients with <12 lymph nodes to those with >or=12 lymph nodes relative to multiple patient and treatment factors.

Results: One hundred seventy-six patients were identified (119 men; mean age, 60.4 y (range, 22-87)). Mean lymph node harvest was 10.1 (range, 1-38). Only 28% had >or=12 lymph nodes and 32% had <6 lymph nodes. There was no statistically significant difference in lymph node harvest relative to radiation dosage, age, tumor response, or type of surgery. There was no correlation between the number of lymph nodes harvested and the number of nodes positive for cancer.

Conclusions: With a standardized surgical technique and pathologic evaluation, the number of lymph nodes present after neoadjuvant chemoradiation and total mesorectal excision for rectal cancer varies greatly.