[A case of osteonecrosis of the jaw during treatment by bevacizumab for sigmoid colon cancer].

A 67-year-old man was diagnosed to have sigmoid colon cancer with peritonitis carcinomatosa. The cancer was surgically resected, and he thereafter underwent chemotherapy with mFOLFOX6+bevacizumab. He complained of gingival swelling throughout treatment and osteonecrosis of the jaw was noted. The bevacizumab therapy was therefore discontinued and the necrotic tissue removed. No recurrent necrosis has occurred. The addition of bevacizumab to the FOLFOX or FOLFIRI chemotherapy regimens has been shown to improve the survival rate and response rate in colorectal cancer. Osteonecrosis of the jaw is a rare toxicity of bevacizumab. Bevacizumab might compromise the microvessel integrity in the jaw, which thus may lead to bone necrosis. Osteonecrosis of the jaw in this case recovered after the discontinuation of bevacizumab and the removal of the necrotic tissue. The pathogenesis and treatment of osteonecrosis have not been elucidated.