ROLE OF INTRAOPERATIVE INDOCYANINE GREEN FLUORESCENCE ANGIOGRAPHY IN PREVENTING ANASTOMOTIC LEAKAGE FOLLOWING COLORECTAL RESECTION IN CYTOREDUCTIVE SURGERY FOR ADVANCED OVARIAN CANCER

Background Complete surgical resection is a pivotal factor for overall survival in patient with advanced ovarian cancer. Bowel resection is a common procedure performed in cytoreductive surgery, with rectosigmoid resection being the most frequently performed. Complications are possible, such as abdominal abscess, fistula formation and anastomotic leakage; the latter is a major complication associated to longer hospitalization, delayed time to ADJ chemotherapy and higher short-term mortality. Decreased tissue oxygenation as a result of poor perfusion is considered a major risk factor for anastomotic leak, however there is no gold standard for intraoperative assessment of anastomotic perfusion. Objective The aim of this study is to evaluate the effectiveness of indocyanine green fluorescence angiography in preventing anastomotic leakage following colorectal resection in patients undergoing cytoreductive surgery for advanced ovarian cancer. Methods Patients with AOC undergoing either primary or interval cytoreductive surgery with colorectal resection at the European Institute of Oncology, Milan from 01/2009 to 12/2023 were identified. All patient with non-comprehensive medical records and/or available written consent for research were excluded. The implementation of ICG-FA to assess anastomotic perfusion at the institution began on 01/2020. The rate of anastomotic leak after colorectal resection was compared between the group using ICG-FA and the group not using ICG-FA. The association between the use of ICG-FA and the occurrence of anastomotic leakage was evaluated with univariate and multivariate analysis. Results In total, 581 patients were identified. Of those, 38 patients had a colorectal anastomotic leak, with an overall anastomotic leakage rate of 6.5%. In 203 patients (34.9%) ICG-FA was used while in 378 patients (65.1%) ICG-FA was not used. The two groups were comparable in terms of clinico-pathological features. 6/203 patients in the group using ICG-FA had a colorectal anastomotic leak and 32/378 patients in the group not using ICG-FA. The rate of leak in ICG group was 3% while in the non-ICG group it was 8.5% (p=0.010). On univariate analysis, the presence of residual tumor, concurrent small bowel resection and concurrent large bowel resection were predictors of colorectal anastomotic leakage, while the use of ICG-FA was a protective factor. On multivariate analysis, concurrent small bowel resection and residual tumor were independent predictors of colorectal anastomotic leakage, while the use of ICG-FA showed an independent protective role. Conclusion These results confirm the role of ICG-FA for the assessment of colorectal anastomosis perfusion in reducing in the rate of colorectal anastomotic leakage. The technique is demonstrated to be both safe and effective. Based on these results, the use of ICG-FA for the assessment of all colorectal anastomosis performed during cytoreductive surgery for AOC can be recommended.