Rectal Sparing Approach After Preoperative Radio and/or Chemotherapy in Patients With Rectal Cancer

The proposed study is an observational, prospective, multicenter study of patients undergoing neoadjuvant therapy for medium-low rectal cancer. Recently the investigators have published the findings of a multicenter Italian phase II study showing that the rate of local recurrence, with a 3 year follow-up, is less than 5% in patients with baseline T2-3 mid-low rectal cancer who, after preoperative chemoradiotherapy (pCRT), showed a major clinical response and underwent a transanal local excision. Based on these results, an organ-sparing approach for patients showing a major clinical response is feasible without reducing the good results obtained with the standard treatment. While a phase III trial is the best way to compare the standard treatment with the organ-sparing approach (local excision or wait-and-see) it is impracticable and likely unethical. An observational study is therefore one of the best way to evaluate the impact that an organ-sparing approach may have on oncological outcomes, quality of life, and bowel function for patients with rectal cancer who, after a pCRT, show a clinical major/complete response. This phase II trial is designed to test the hypothesis that conservative treatments, in patients with low-mid rectal cancer who undergo a major or complete clinical response after neoadjuvant treatment, will be safe and effective compared to standard surgery. The investigators will compare rectum-sparing approaches to standard surgery, firstly in terms of rate of organ preservation at 2 years. Additionally they will compare survival outcomes (DFS, OS), stoma rates, clinical and tumor factors related to pathological complete response, correlation between major and complete clinical response. To add value, the investigators will measure QoL in patients treated with rectum-sparing approaches in comparison to patients treated with standard surgery (TME or abdomino-perineal amputation). Rectum-sparing approach can be considered clinically acceptable if