A case report of vesicovaginal fistula following Bevacizumab without pelvic disease and radiochemotherapy.

Background: Bevacizumab has gradually become an important adjuvant therapy for many advanced tumors including lung cancer. Although it can improve the survival of many cancer patients, it also brings many adverse reactions, including fistula formation. However, vesicovaginal fistula in the absence of pelvic lesions and radiation history has not been reported before. Case Description: We diagnosed an advanced non-small cell lung cancer patient with left pleural, bone and liver metastases in February 2017. She then received Gefitinib-targeted therapy. Ten months later, liver metastases achieved complete remission and the remaining metastases partial response. Then she received whole brain radiotherapy (30 Gy/10 F) for new brain metastases, and Oxitinib was used to replace Gefitinib. In March 2018, the patient underwent TVT-O sling surgery for stress urinary incontinence, and recovered well after the operation. The patient was treated with Bevacizumab at 400 mg once every 3 weeks in March 2019 because of the poor efficacy of Oxitinib. After using bevacizumab for 3 months, the patient complained about frequent urination, urgency, dysuria, and vaginal leakage. The presence of vesicovaginal fistula was confirmed by color Doppler ultrasound and positron emission tomography/computed tomography (PET-CT). After discontinuation of Bevacizumab, urine leakage was disappeared. Conclusions: Bevacizumab can also cause vesicovaginal fistula, even without pelvic lesions and radiotherapy. Previous pelvic surgery and foreign materials implantation may be factors that promote the formation of vesicovaginal fistula.