Is there a role for adjuvant chemotherapy in pathological complete response rectal cancer tumors following neoadjuvant chemoradiotherapy?

To investigate the contribution of neoadjuvant chemotherapy in rectal cancer patients with pathological complete response (pCR).

Data were collected on all consecutive locally advanced rectal cancer patients treated with neoadjuvant chemotherapy and later resected in our institution between 2001 and 2013. Surgery was performed by a single proctology team, and tumor specimens were evaluated by the hospital pathologists.

The medical records of 260 patients were analyzed, and 54 patients of those patients were found to have achieved pCR (20.8 %). Two of those patients were lost to follow-up. Thirty-five of the 54 pCR patients received adjuvant chemotherapy (Group A) and 17 did not (Group B). With the sole exception of the Group A patients being younger than the Group B patients (60.9 ± 11.9 vs. 68.7 ± 10.8 years, respectively, p = 0.0272), all other evaluated parameters were identical between the two groups. There was no advantage for the administration of adjuvant chemotherapy for disease-free survival (DFS) and overall survival (OS).

Adjuvant chemotherapy played no part in disease-free survival and OS of patients with rectal cancer who had been treated with neoadjuvant chemotherapy and achieved pCR. Our findings indicate a tendency for adjuvant chemotherapy to be administered to younger rectal cancer patients. A randomized trial should be conducted to resolve the question of whether they derive any benefit from it.