IOSR Journal of Dental and Medical Sciences (IOSR-JDMS) e-ISSN: 2279-0853, p-ISSN: 2279-0861.Volume 20, Issue 8 Ser.10 (August. 2021), PP 23-26 www.iosrjournals.org DOI: 10.9790/0853-2008102326 www.iosrjournal.org 23 | Page Small Bowel Perforation in Non-Squamous Non-Small Lung Cancer after Bevacizumab Therapy: A Case Report Nikolaos Tepelenis 1 , Kostas Tepelenis 2* , Stefanos K. Stefanou 3 , Christos K. Stefanou 4 ,George Gogos-Pappas 1 , Konstantinos Vlachos 1 1 Department of Pathology, Agia Sofia Children’s Hospital, Athens, 11527, Greece. 2 Department of Surgery, University Hospital of Ioannina, Ioannina, 45500, Greece. 3 Department of Surgery, General Hospital of Ioannina “G. Xatzikosta”, Ioannina, 45500, Greece. 4 Department of Surgery, General Hospital of Filiates, Filiates, 46300, Greece. Corresponding author: Kostas Tepelenis MD, MSc Abstract Background: Bevacizumab-associated gastrointestinal perforation reported incidence is less than 1%, with a mortality of 15-20%. Case presentation: Herein, we report a 75-year-old male was diagnosed with metastatic non-small cell adenocarcinoma of the left lung. Fifteen days after the first cycle of chemotherapy (carboplatin, paclitaxel, and bevacizumab), the patient experienced abdominal pain. A fluid collection10 x 4 cm adjacent to small bowel loops containing air was noted on the computed tomography. Unfortunately, the percutaneous drainage of the collection was not feasible, and the patient underwent exploratory laparotomy. Intraoperatively, an enterectomy with side-to-side anastomosis due to necrosis and perforation of the bowel wall, and drainage of the intra- abdominal abscess were carried out. Conclusion: Bevacizumab-associated gastrointestinal perforation is a potentially fatal complication. Its diagnosis could be challenging due to immunosuppression. The management is complex and requires a multidisciplinary approach that engages surgeons, interventional radiologists, and oncologists. Keywords: Bevacizumab; non-squamous non-small cell lung cancer; gastrointestinal perforation; complications; management. --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 06-08-2021 Date of Acceptance: 20-08-2021 --------------------------------------------------------------------------------------------------------------------------------------- I. Introduction Bevacizumab (Bev), a recombinant human monoclonal antibody that deactivates vascular endothelial growth factor (VEGF), is widely used in the treatment of locally advanced or metastatic colon cancer, cervical cancer, non-squamous non-small cell lung cancer (non-squamous NSCLC), and glioblastoma multiforme (1). In non-squamous NSCLC, Bev combined with other chemotherapeutic agents prolongs overall survival and improves progression-free survival and response rate (2, 3). Generally, Bev is well-tolerated with acceptable toxicity. The typical side effects include hypertension and proteinuria. Other rare complications encompass epistaxis, gastrointestinal bleeding, pulmonary bleeding, arterial or venous thrombosis, and delayed wound healing (4, 5). One potentially fatal complication is Bev-associated gastrointestinal perforation (BAP), which has a high mortality. The reported incidence of BAP is less than 1%, with a mortality of 15-20%. The most typical site of perforation is the large bowel, followed by the small intestine and stomach. Although several theories have been proposed to explain the development of BAP, the exact mechanism remains unclear (6, 7). Diagnosis of BAP is challenging as typical symptoms and signs of gastrointestinal perforation might be absent due to immunosuppression. The optimal management of BAP is complex and requires a multidisciplinary approach that engages surgeons, interventional radiologists, and oncologists (1). II. Case presentation A 75-year-old male was diagnosed with metastatic non-small cell adenocarcinoma of the left lung with bilateral lung metastases two months ago. He was scheduled for palliative chemotherapy containing carboplatin, paclitaxel, and bevacizumab. Fifteen days after the first cycle of chemotherapy, the patient appeared to the emergency department with a six-day history of abdominal pain localized in the left upper quadrant associated with vomiting and diarrhea. No history of fever, constipation or urinary complaints was noted. The patient