[Ischemic anastomotic bowel perforation during treatment with bevacizumab 10 months after surgery]

Bevacizumab (Avastin) is a monoclonal antibody against vascular endothelial growth factor (VEGF) receptor that has demonstrated increased overall survival when added to standard chemotherapy regimens in patients with metastatic colorectal cancer. Gastrointestinal perforation is a known risk factor of unknown etiology associated with the use of bevacizumab.

We report a 61-year-old woman with adenocarcinoma of the colon ascendens who underwent hemicolectomy and adjuvant chemotherapy with oxaliplatin, 5-fluorouracil, and leucovorin. Eight months after the operation, we started therapy with bevacizumab combined with irinotecan, 5-fluorouracil, and leucovorin due to disease progression. Two months after completion of this therapy, ischemic anastomotic bowel perforation occurred and a resection of the anastomosis was performed. Because of anastomotic insufficiency 8 days later, a further revision had to be done and the terminal ileum and the colon were brought out through a stoma.

This case is unusual because the time interval between the primary operation and the application of bevacizumab is regarded as safe with regard to the risk of perforation. An ischemic genesis of the perforation was considered on the basis of the histopathological workup. In case of perforations during therapy with bevacizumab, a safe surgical approach should be preferred, i.e., a transient stoma instead of a primary reconstruction of the bowel passage.