Preoperative short-course radiotherapy in rectal cancer patients: results and prognostic factors

The purpose of this study was to evaluate the clinical outcome of preoperative short-course radiotherapy for rectal cancer patients. The study group comprised 210 patients with pathologically proven resectable rectal cancer. Between 2001 and 2013, they were treated preoperatively with short-course radiotherapy (25 Gy delivered in five fractions), followed by total mesorectal excision. Adjuvant 5-fluorouracil-based chemotherapy was administered at the discretion of the treating physician, depending on the pathological stage. After a median follow-up of 57 months, the following 5-year survival rates were observed: overall survival-66.4%, disease-free survival-67.2%, locoregional relapse-free survival-91.7%, and distant metastases-free survival-71.5%. The local failure was observed in 15 patients. Ten patients (4.8%) achieved pathologic complete response. The multivariate analysis demonstrated the regional lymph node involvement to be statistically significant for unfavorable outcomes in terms of all estimated survival rates. Lymphovascular invasion was found to be a strong predictor of survival (HR = 1.68; 95% CI 1.29-3.55) and treatment failure (HR = 1.54; 95% CI 1.08-3.34). The presence of positive surgical circumferential margin was related to six times higher risk of locoregional recurrence. Early and late severe treatment-induced toxicity was reported in 1 and 7.6% patients, respectively. Preoperative short-course radiotherapy followed by total mesorectal excision and adjuvant chemotherapy allows to achieve excellent local control and favorable survival rates. The treatment-induced toxicity is acceptable.