Pathological Response Has Survival Benefits for Rectal Cancer following Neoadjuvant Therapy
Abstract Background Studies reporting the results of associated factors of pathological completed response (PCR) and tumor regression response in patients with rectal cancer following neoadjuvant chemoradiation therapy (nCRT) are inconsistent. The purpose of this study was to identify the prognostic factors of tumor response and outcome in rectal cancer patients.Methods The study was a retrospective analysis. Patients with locally advanced rectal cancer underwent nCRT followed by surgery from 2010 to 2014 with 5 years of follow-up. The primary outcomes were associated factors of pathological completed response and downstaging. The risk factors of survival outcome and disease recurrence were also observed.Results A total of 169 rectal cancer patients were included. The PCR rate was 17.8%, and the downstaging rate was 60.9%. Patients with a histology type of adenocarcinoma associated with PCR, and patients positive for clinical N stage were associated with downstaging. Kaplan-Meier analysis showed the PCR group performed better to a statistically significant level both in overall survival and disease recurrence free survival than the no PCR group (p= 0.033 & 0.025, respectively). Patients with a downstaging response also showed better overall survival benefits and disease recurrence free survival benefits than their counter-parts (both p<0.001). After controlling confounding variables, the risk factors of overall survival were downstaging [Hazard Ratio (HR): 0.40, 95% CI: 0.21-0.74], male, abnormal post-nCRT CEA level and abnormal Hb level. In addition, the protective factors of recurrence were downstaging and having adjuvant chemotherapy.Conclusions Among rectal cancer patients who received the neoadjuvant therapy, histology type and clinical N stage were associated with PCR and downstaging, respectively. Downstaging was an important protective factor for better overall survival and recurrence free survival.