Tumor-bowel fistula: what radiologists should know.

Tumor-bowel fistula is an under reported complication of abdomino-pelvic malignancies which may occur spontaneously due to tumor growth or can be associated with cancer treatment. Chemotherapy and radiotherapy are commonly responsible for tumor-bowel fistulas. Molecular targeted therapies are a new class of drugs that can cause tumor fistulization due to their antiangiogenic properties. Clinically, the fistula can be asymptomatic or can result in devastating complications. Imaging helps in the prompt detection of these fistulas and the complications associated with them. Management of tumor-bowel fistula is individualized but often involves discontinuation of the associated treatment. Radiologists should promptly alert the oncology team about the presence of tumor-bowel fistula and any risk factors for its occurrence like pneumatosis or large metastatic deposits close to bowel loops.