Value of postoperative adjuvant chemotherapy in locally advanced rectal cancer patients achieving pathologically complete response after operation following concurrent three-dimensional conformal radiotherapy and chemotherapy

Objective: To investigate the value of postoperative adjuvant chemotherapy in the patients with locally advanced rectal cancer who achieved a pathologically complete response (pCR) after operation following concurrent three-dimensional conformal radiotherapy (3DCRT) and chemotherapy. Methods: Retrospective analysis was performed on the clinical records of 49 patients with locally advanced rectal cancer, who achieved a pCR after operation following concurrent 3DCRT and chemoradiotherapy in our center from August 2005 to October 2010. These patients were divided into group A (n = 38) that received postoperative adjuvant chemotherapy and group B (n = 11) that did not receive postoperative adjuvant chemotherapy. The two groups were compared in terms of treatment outcome. Results: The follow-up rate was 100%; 22 patients were followed up for at least 3 years. The 3-year overall survival rate, relapse-free survival rate, and cancer-specific survival rate of all patients were 92%, 90%, and 95%, respectively; group A and group B had overall survival rates of 90% and 100% (χ² = 0.05, P = 0.818), relapse-free survival rates of 92% and 80%(χ² = 1.00, P = 0.316), and cancer-specific survival rates of 94% and 100% (χ² = 0.31, P = 0.581). The 3-year recurrence rate of all patients was 8%; group A and group B had 3-year recurrence rates of 8% and 9% (χ² = 1.00, P = 0.316). Conclusions: The patients with locally advanced rectal cancer who achieve a pCR after operation following concurrent 3DCRT and chemotherapy have low cumulative recurrence rate. Postoperative adjuvant chemotherapy does not improve the clinical outcomes in these patients. Because of short follow-up period and small number of subjects in this study, the effect of postoperative adjuvant chemotherapy needs to be further investigated in randomized controlled clinical trial. (authors)