Lessons learned: The 5-year oncologic outcomes from the trial regimen were excellent. However, the neoadjuvant and surgical toxicity of this regimen was significant and was the primary reason for the low compliance with adjuvant systemic therapy.Due to the lack of an improvement in the pathologic complete response rate, the substantial associated toxicity, and the negative phase III trials of adjuvant bevacizumab in colon cancer, this regimen will not be pursued for further study.
Background: The addition of bevacizumab to chemotherapy improves overall survival for metastatic colorectal cancer. We initiated a phase II trial to evaluate preoperative capecitabine, oxaliplatin, and bevacizumab with radiation therapy (RT) followed by surgery and postoperative 5-fluorouracil, leucovorin, oxaliplatin (FOLFOX), and bevacizumab for locally advanced rectal cancer. The purpose of this report is to describe the 5-year oncologic outcomes of this regimen.
Methods: In a phase II Simon two-stage design study, we evaluated preoperative treatment with capecitabine (825 mg/m(2) b.i.d. Monday-Friday), oxaliplatin (50 mg/m(2) weekly), bevacizumab (5 mg/kg on days 1, 15, and 29), and RT (50.4 Gy). Surgery was performed by 8 weeks after RT. Beginning 8-12 weeks after surgery, patients received FOLFOX plus bevacizumab (5 mg/kg) every 2 weeks for 12 cycles (oxaliplatin stopped after 9 cycles). The primary endpoint was a pathologic complete response (path-CR) rate of 30%. Fifty-seven patients with resectable T3/T4 rectal adenocarcinoma were enrolled between 2006 and 2010.
Results: Of 57 enrolled patients, 53 were eligible and included in the analysis. Forty-eight (91%) patients completed preoperative therapy, all of whom underwent curative surgical resection. Nine patients (17%) achieved path-CR. There were 29 worst grade 3 events, 8 worst grade 4 events, and 2 patient deaths, 1 of which was attributed to study therapy. Twenty-six patients (54%) began adjuvant chemotherapy. After a median follow-up period of 41 months, the 5-year overall survival (OS) rate for all patients was 80%. Only 2 patients experienced cancer recurrence: 1 distant (liver) and 1 loco-regional (pelvic lymph nodes), respectively. Both of these patients are still alive. The 5-year relapse-free survival rate was 81%.
Conclusion: Despite the path-CR primary endpoint of this trial not being reached, the 5-year OS and recurrence-free survival rates were excellent. However, the neoadjuvant and surgical toxicity of this regimen was significant and was the primary reason for the low compliance with adjuvant systemic therapy. Because of the lack of an improvement in the path-CR rate, the substantial associated toxicity, and the negative phase III trials of adjuvant bevacizumab in colon cancer, this regimen will not be pursued for further study.
Trial registration: ClinicalTrials.gov NCT00321685.
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