Long-term oncologic outcomes in pathologic tumor response after neoadjuvant chemoradiation for locally advanced rectal cancer

Abstract

Purpose: The status of tumor regression in rectal cancer after neoadjuvant concurrent chemoradiotherapy (CCRT) has significant effect on tumor recurrence and patient survival. The aim of this study was to evaluate the long-term oncologic outcomes of rectal cancer patients presenting complete response or down-staging of rectal cancer compared to patients with non-response after neoadjuvant therapy in advanced mid-to-lower rectal cancer. Methods: We retrospectively reviewed 79 patients with stage II/III mid-to-lower rectal cancer following neoadjuvant CCRT between March 2003 and April 2012. Patients were classified into three groups according to down-staging tumor response after neoadjuvant CCRT: complete response group (CRG), partial response group (PRG), and non-response group (NRG). Results: Of the 79 patients in the study, eight (10.1%), 31 (39.2%), and 40 (50.7%) were classified as CRG, PRG, and NRG, respectively. Median follow-up period was 57 months. There was significant difference in local recurrence (P=0.012) between the three groups, yet there was no significant difference in overall survival (CRG, 100%; PRG, 82.5%; NRG, 74.0%; P=0.244). There was a significant difference in disease- free survival (CRG, 100%; PRG, 90.1%; NRG, 57.7%; P=0.006). Conclusion: Tumor response with complete response or down-staging provided better oncologic outcomes in terms of disease-free survival and local recurrence in locally advanced rectal cancer patients.