Analysis of bevacizumab-based preoperative radiochemotherapy in patients with locally advanced rectal cancer on surgery-associated spectrum of complications

Background. Preoperative radiochemotherapy (RCT) is a standard of care for patients with locally advanced rectal cancer (LARC; stages II and III). Results of our phase II study (BevXelOx-RT) have shown that this regimen is feasible but without a significant improvement of pathological complete response. Whether preoperatively administered bevacizumab, due to its specific toxicity profile, leads to increased rates of surgical complications is currently a subject for debate. This analysis focusses on the surgery-associated spectrum of complications. Methods. Data from 62 patients with rectal cancer (uT3-4; N0/1, M0) of the phase II trial were analyzed. Patients received radiotherapy (50.4/1.8 Gy fractions), simultaneous bevacizumab 5 mg/kg (d1, d15, d29), and capecitabine 825 mg/m² twice daily (d1-14, d22-35), oxaliplatin 50 mg/m² (d1, d8, d22, d29). Four to six weeks after RCT, surgical resection was performed. Results. Overall, 69/69 patients underwent surgery, and 66 (95.7 %) patients had R0 resection. Surgery was mainly conducted (in 66 %) by highly experienced surgeons (>20 resections of rectal cancer/year) with differences between the institutions due to the operative procedures but without effects on the rate of R0 resection or complications. The average duration of surgery was 239 min (±10). Frequency of multivisceral resections (11 %), intraoperative (8 %) and postoperative (43 %) complications were all in the expected range. In particular, we did not observe an increased rate of postoperative bleedings (3 %). The postoperative mortality rate was 0 %. Conclusions. Quantity and the kind of surgery-associated spectrum of complications followed by a preoperative bevacizumab-containing RCT regimen in patients with LARC were in line with comparable trials of bevacizumab-based approaches.