Comprehensive geriatric assessment (CGA) is a diagnostic method to assess the physical and mental health status of older patients. The purpose of this study was to assess the safety and efficacy of preoperative concurrent chemoradiotherapy (preCRT) for intermediate or locally advanced rectal cancer in older people who were classified as "fit" by CGA. The interim analysis focusing on safety was reported here as the first part of this trial. This is a single arm, multicenter, phase II trial. The eligible patients for this study were aged 70 years or above that fulfilled the standard of intermediate or locally advanced risk category, and met the standard of fit (SIOG1) evaluated by CGA. All patients received preCRT (50 Gy) with Raltitrexed (3 mg/m2 on d1 and d22). Qualitative and quantitative variables were described using descriptive statistics. The surgery adherence predicting was analyzed by multivariate logistic regression. Thirty-nine fit patients were enrolled. All patients except one finished radiotherapy without dose reduction. Thirty-two patients finished the prescribed Raltitrexed therapy as scheduled. A serious toxicity was observed in 12 patients (30.8%), and only six patients (15.4%) experienced non-hematological side effects. Overall, our results showed that preCRT was feasible and safe in older patients with rectal cancer who were evaluated as fit based on CGA, supporting the use of CGA to tailor oncological treatment and predict the tolerance of a specific therapy. Completing this trial as planned would provide further valuable insights. Copyright © 2020. Published by Elsevier Ltd.