Outcomes of Neoadjuvant Radiochemotherapy of Locally Advanced Rectal Adenocarcinoma: Results of 8 Year Experience in Iran Cancer Institute

Background: Colorectal carcinoma is one of most common cancers in Iran with increasing incidence. The mean age of the affected is decreasing. With progresses in multimodality treatment, we witnessed improved prognosis in colorectal cancers. Objectives: This study aimed at evaluating the outcomes of patients with rectal adenocarcinoma treated with neoadjuvant chemoradiotherapy followed by surgery. Methods: In this retrospective cohort study, we assessed the oncologic treatment outcomes of patients with locally advanced (T3-4 or N+ve) rectal adenocarcinoma in our high volume cancer center, Iran cancer institute, Tehran, Iran. Patients with synchronous metastasis, previous malignancy, and history of pelvic radiation were excluded. The primary endpoint was overall survival (OS) rate and secondary endpoints were disease-free survival and pathologic response. Results: Of patients being treated between 2008 and 2014, 158 were entered to final analysis; they completed planned neoadjuvant treatment and retuned after surgery with pathology report. The mean age was 56 years and mean interval from radiotherapy to surgery was 9 weeks. Thirty percent achieved pathologic complete response. Two-year overall and disease-free survival rate was 87% and 80%, respectively. In multivariate analysis age, sex, local recurrence, clinical stage, and radiotherapy to surgery interval failed to predict OS. The pathologic response (complete vs. non-complete) and the absence of distant metastasis were independent predictors of OS. Conclusions: The rate of pathologic response and survival in our series was comparable to other big randomized studies in the world and even better than previous national reports. These findings emphasize the necessity of treating patients with locally advanced rectal cancer in high volume centers.