OGC P30 Prophylactic HIPEC and Intro-Operative Radiotherapy (IORT) in the Management of Gastric Cancer: An international retrospective case-control study

Abstract

Abstract Background The combination of surgery and peri-operative chemotherapy is a well-established cornerstone of treatment with curative intent for gastric cancer in the UK. However, this approach has not necessarily been adopted globally. Hyperthermic intraperitoneal chemotherapy (HIPEC) and intraoperative radiation therapy (IORT) may improve survival amongst patients with advanced gastric cancer, however the evidence base for its use is limited and its efficacy remains unclear. The present study investigated the effectiveness of prophylactic HIPEC and IORT compared to peri-operative chemotherapy and gastrectomy in patients with gastric cancer. Methods A retrospective study including patients with gastric adenocarcinoma (stages 1-3) between 2014 and 2020 was undertaken. All patients received peri-operative chemotherapy and radical gastrectomy in an academic surgical centre in the Kingdom of Saudi Arabia or a regional tertiary oesophago-gastric centre in the North-West of England. Two groups were formed – one (study group – KSA; HIPEC-IORT) which also received combined prophylactic HIPEC and IORT and one which did not (control – UK; CS). Three parameters were utilized as control variables (age, gender, tumour stage and location). 2:1 matching between the control and study group (86 vs 43 patients) was performed. Results Mean age was 60 (SD = 14.5; 81.5% male). R0 rates were 74.5% in the HIPEC-IORT group vs 82.5% in the CS group. LVI and PNI rates were higher in the HIPEC-IORT group (55.8% vs 32.6%)(55.8% vs 32.6%) as were rates of diffuse-type morphology (39.5% vs 17.5%). Pathological stage distribution in the study group was different (37.2% II and 62.8% III) vs (31.4% I, 34.9% II, 33.7% III). Cox regression analysis which controlled for age, gender, and cancer stage, found no difference in survival between HIPEC-IORT and CS groups (p=0.219). Conclusions The findings of the present study suggest that the combination of prophylactic HIPEC and IORT following radical gastrectomy cancer does not significantly improve survival. Further exploration which compares the short-term outcomes of both approaches is required. These results should be interpreted with caution as the groups showed morphologically different tumour-types. A larger prospective study which controls for more variables may be warranted.