Long-term Survival and Propensity Score Matched Outcomes of Bilateral vs. Unilateral Diaphragm Interventions in Cytoreductive Surgery plus Intra-peritoneal Chemotherapy

Background/Aim: To assess the impact of short- and long-term outcomes of bilateral vs. unilateral diaphragm interventions in cyto-reductive surgery (CRS) and intra-peritoneal chemotherapy (IPC). Patients and Methods: A total of 652 CRS/IPC procedures, between 1996 and 2018, required diaphragm interventions. Among these, 388 underwent bilateral intervention. Preoperative heterogeneity was assessed in 6 parameters and addressed with propensity score matching. The association of each respective analysis was assessed with 11 outcomes. Overall survival was assessed based on histology. Results: CRS/IPC requiring bilateral diaphragmatic interventions illustrated significantly increased operative hours (9.6 vs. 8.6 hours, p<0.001). Postoperatively, there was significantly increased red blood cell (RBC) transfusion (6.37 units vs. 4.47 units, p=0.007) and grade III and IV complications (57.3% vs. 40.6%, p=0.004). No difference was noted in ICU stay, total length of stay, hospital death and return to OT. In terms of respiratory complications, an increased incidence of pneumothorax (16.5% vs. 6.2%, p<0.001) was noted whilst pleural effusions and pneumonia occurrences were non-significant. Overall survival, revealed bilateral interventions in low-grade appendiceal mucinous neoplasm conferred an increased relative risk (p=0.037, RR=2.230, 95%CI=1.052-4.730). They did not have an effect on OS in colorectal cancer and mesothelioma. Conclusion: Despite the increase in short-term morbidity, bilateral diaphragm interventions resulted in similar long-term survival to unilateral interventions.