Methods: This trial aim to evaluate induction treatment with CAPOX, followed by short-course radiotherapy consolidation chemotherapy with CAPOX. After 5-7 weeks, patients will be evaluate by MRI. Patients with incomplete clinical response will be referred to immediate surgery and patients with complete clinical response will be managed with watch and wait approach. Patients with progression disease during the treatment phase will be withdrawn from the study and will receive their treatment according to the investigator's judgment.~The sample size was calculated according to Simon's optimal two-stage design. Accordingly, 21 patients must be included in each group during the first stage and 24 during the second stage. Treatment regimen will be considered effective if 9 or more patients show good response (final analysis), reaching 80% power with an alpha of 0.10 level of significance.
Short-course radiotherapy followed by consolidation chemotherapy has shown a better response rate when compared to chemoradiotherapy treatment.~In addition, recent studies have shown better tolerance with total neoadjuvant treatment, with induction or consolidation chemotherapy. Induction chemotherapy could reduce the size of the tumor, treat micrometastases early and allow treatment to start immediately (avoiding potential delays in waiting for radiotherapy). While consolidation chemotherapy allows longer waiting times for surgery, with higher response rates.