Tumor fistulization associated with targeted therapy: Computed tomographic findings and clinical consequences

Purpose: To describe the computed tomographic (CT) appearances and clinical consequences of tumor fistulization as a complication of targeted therapy for cancer. Methods: The committee on human research approved this Health Insurance Portability and Accountability Act-compliant study and waived written informed consent. Based on the records of the senior author and our multidisciplinary Tumor Boards, we retrospectively identified 4 patients (1 man and 3 women with a mean age of 55.25 years; range, 47 to 64 years) who developed tumor fistulization while being treated with targeted therapy consisting of sunitinib (n = 2); bevacizumab (n = 1); and XL184, an investigational c-Met inhibitor (n = 1). All available clinical, imaging, and histopathological records were reviewed, with particular emphasis on treatment administered, CT findings, and clinical course. Results: All 4 patients developed fistulae from large metastatic deposits in the abdomen (mean size before treatment, 10.55 cm; range, 7.4-13.4 cm) to the gastrointestinal tract, and one patient also developed fistulae from a lung metastasis of undetermined size to the bronchial tree. All fistulae manifested as the appearance of air within a pre-existing tumor mass. At the time of fistula detection, disease at other sites in the 4 patients showed signs of regression (n = 1), progression (n = 2), or stability (n = 1). Currently, one patient is alive without evidence of disease, and the 3 other patients are deceased. Conclusions: Targeted therapy can be associated with tumor fistulization to the gastrointestinal tract or tracheobronchial tree; familiarity with the CT findings should facilitate the diagnosis of this complication, which seems to be of variable and patient-specific prognostic significance.