Long term survival and perioperative propensity score matched outcomes in diaphragmatic interventions in cytoreductive surgery + intra-peritoneal chemotherapy

Objectives To assess the impact of short and long term outcomes of diaphragmatic interventions in cyto-reductive surgery (CRS) and intra-peritoneal chemotherapy (IPC). Methods 1230 consecutive CRS/IPC procedures were preformed between 1996 and 2018 in Sydney, Australia. Redo procedures and incomplete cyto-reductions were excluded. Among these, 599 underwent diaphragmatic intervention. Preoperative heterogeneity was assessed for in 6 parameters and addressed with propensity score matching. CRS/IPC requiring diaphragmatic interventions were compared to CRS/IPC without diaphragmatic involvement. Ten perioperative outcomes were measured. Overall survival was assessed based on diagnosis type. Results Intraoperative results revealed a significant increase in operative hours (7.85 vs. 7.28, p = 0.033). Transfusion requirements were insignificantly different. Postoperatively, increased grade III and IV complications (36% vs. 26%, p = 0.052) were noted. There was no difference with regards to intensive care stay, hospital length of stay, hospital death and return to theatre. In terms of respiratory specific complications, an increased incidence of pneumothorax (13% vs. 3%, p = 0.001) and pleural effusions (24% vs. 16%, p = 0.043) were noted, whilst the differences in pneumonia were insignificant. Overall survival revealed diaphragm interventions; did not affect survival outcomes in colorectal cancers (p = 0.750, RR = 1.077, CI 0.683–1.697) and increased relative risk in low-grade appendiceal mucinous neoplasms (p = 0.025, RR = 2.437, CI 1.121–5.298). Conclusion After our three-tiered research strategy, we conclude that despite the marginal increase in short term morbidity; diaphragmatic interventions do not decrease survival in colorectal cancers and diaphragmatic disease in LAMNs maybe an independent prognosticator of disease aggression.