This phase II trial is studying the efficacy and safety of total neoadjuvant treatment for MRI defined high-risk locally advanced rectal cancer.~MRI imaging features as mrT3c/T3d/T4a/T4b, threatening circumferential resection margin, mrN2 disease or extramural vascular invasion are defined as high-risk factor and proved to associated with unfavorable oncological outcome, especially for distant metastasis. Induction and consolidation chemotherapy plus radiation may increase both systemic and local control. Total neoadjuvant treatment schedule also has advantages as improved patient tolerance, early closure of defunctioning ileostomy etc.~In this study, patients with MRI defined high-risk rectal cancer will receive 3 cycles induction CapeOX, intensity modulated radiotherapy with concurrent capecitabine and 2 cycles consolidation CapeOX and Total mesorectal excision.~The induction chemotherapy related G3-4 toxicity occurred in 42% of patients in GCR-3 trial (23% during RT, 19% during induction chemotherapy). It is hypothesized that the neoadjuvant chemotherapy related G3-4 toxicity rate of the present regimen will be lower than 25% (10% during IMRT, 15% during induction/consolidation chemotherapy). A sample size of 67 achieves 80% power to detect a difference (△P =17%, P1=25%, P0=42%) using a one-sided binomial test. (α= 0.05). If the number of G3-4 toxic event is 21 or less, the hypothesis that P1>= 42% is rejected. About 10 % loss to follow-up was anticipated, so an additional eight patients will be recruited. The study requires 75 subjects in all.
This study is designed to test the efficacy and safety of total neoadjuvant induction and consolidation CapeOX plus neoadjuvant intensity modulated radiotherapy with concurrent capecitabine for MRI defined high-risk rectal cancer.