Background: Lymph node status is important in staging colorectal cancer. The use of combination treatment for pathological T3N0 (pT3N0) rectal cancer patients has been controversial. We aimed to explore the prognostic significance of the total number of lymph nodes harvested from pT3N0 rectal cancer patients.
Methods: Between June 2004 and November 2011, 289 pT3N0 rectal cancer patients who received total mesorectal excision (TME) with or without postoperative chemotherapy were retrospectively reviewed. The main independent variable was the total number of harvested lymph nodes, and the endpoints included local recurrence-free survival (LRFS), disease-free survival (DFS), and overall survival (OS).
Results: The patients had a median of 13 lymph nodes harvested. When compared with patients who had < 12 lymph nodes harvested, patients who had ≥12 lymph nodes harvested had higher 5-year LRFS (84.7% vs. 98.0%, P < 0.001), DFS (71.4% vs. 86.8%, P < 0.001), and OS (77.6% vs. 94.9%, P < 0.001) rates. Multivariate analysis demonstrated that the patients who had ≥12 lymph nodes harvested had a significantly lower risks of local relapse (hazard ratio [HR], 0.099; P < 0.001), treatment failure (HR: 0.291; P < 0.001), and death (HR: 0.231; P < 0.001) when compared with patients who had <12 lymph nodes harvested.
Conclusions: The number of lymph nodes harvested was independently associated with local relapse, treatment failure, and OS rates in pT3N0 rectal cancer patients who received initial TME with or without postoperative chemotherapy. Postoperative radiotherapy should not be omitted for pT3N0 rectal cancer patients who had <12 lymph nodes harvested.
Keywords: Prognostic significance; T3N0; radiotherapy; rectal cancer; total number of lymph nodes.