LAUSR

Background/Aim: This study sought to investigate the difference in survival outcomes in patients with complete cytoreduction (CC)-0 or CC-1 mucinous appendiceal cancer undergoing cytoreductive surgery (CRS) and heated intraperitoneal chemotherapy (HIPEC). It also investigated what effect early postoperative intraperitoneal chemotherapy (EPIC) may have on survival based on CC score and histology. Patients and Methods: This was a retrospective single centre study of patients that underwent CRS/HIPEC +/− EPIC for mucinous appendiceal neoplasms from June 2003 to February 2022. Results: A total of 545 patients were identified. Although there was a survival difference between CC-0 and CC-1 on univariate analyses, this was not statistically significant on multivariate analysis. Histology, peritoneal cancer index, and EPIC status were demonstrated to be independent factors that affected overall survival (OS) on multivariate analysis. Patients with CC-1 that received EPIC had significantly improved OS (mean OS 14 years) when compared to patients that did not receive EPIC (mean OS 6 years). In CC-1, OS was significantly improved in patients that received EPIC in both low-grade (p<0.001) and high-grade (p=0.012) disease. OS for patients that received EPIC at 1, 5, and 10 years was 95%, 80%, and 59%, respectively. OS for patients that did not receive EPIC at 1, 5, and 10 years was 84%, 49%, and 30%, respectively. Conclusion: There was no difference in OS between CC-0 and CC-1. The implementation of EPIC in patients with CC-1 significantly improved OS in both low-grade and high-grade disease and thus we recommend its addition in CC-1 disease to achieve optimal survival outcome.