Neoadjuvant oxaliplatin and capecitabine combined with bevacizumab plus radiotherapy for locally advanced rectal cancer: results of a single-institute phase II study

Background: Neoadjuvant chemoradiotherapy followed by surgery is recommended as the standard of care for locally advanced rectal cancer, reducing local recurrence but not distant metastasis. Intensified systemic therapy is warranted to reduce the risk of distant metastasis. The present study aimed to evaluate the safety and efficacy of neo-adjuvant oxaliplatin and capecitabine (XELOX) combined with bevacizumab plus radiotherapy for locally advanced rectal cancer. Methods: Patients with stages II to III rectal cancer received one cycle of induction chemotherapy and concurrent chemoradiotherapy with XELOX plus bevacizumab. Surgery was performed 6-8 weeks after completion of radiotherapy, and postoperative chemotherapy with three cycles of XELOX and two cycles of capecitabine were given. The primary endpoints were pathologic complete response (pCR) rate and safety, and the secondary endpoints were 3-year overall survival and progression-free survival. Results: Forty-five patients were enrolled between February 2013 and April 2015. All completed the neoadjuvant therapy. Seven patients (15.6%) refused subsequent surgical therapy for personal reasons, and the other 38 patients received radical resection, with a sphincter preservation rate of 84.2% and a pCR rate of 39.5%. Toxicity was acceptable, with grades 3-4 hematological toxicity and diarrhea observed in six and two patients, respectively. Incidence of anastomotic leak that required surgical intervention was 13.3%. After a median follow-up period of 37 months, five patients developed disease progression and two died of cancer. The 3-year overall survival rate and 3-year progression- free survival rate were 95.3% and 88.6%, respectively. Conclusions: The addition of bevacizumab to neoadjuvant chemoradiotherapy resulted in a satisfying pCR rate and 3-year survival, but also may increase the risk of anastomotic leak, thus this regimen is not suitable to be considered for regular recommendation for locally advanced rectal cancer.