Surgery combined with intraoperative hyperthermic intraperitoneal chemotherapy (IHIC) for gastric cancer: a systematic review and meta-analysis of randomised controlled trials.

Background: Adjuvant intraoperative hyperthermic intraperitoneal chemotherapy (IHIC) is a therapy which combines thermotherapy and intraperitoneal chemotherapy. It is theoretically powerful for patients with advanced gastric cancer (AGC), but is there evident advantage in clinical practice? We need evidence to guide our decision-making.

Objectives: Meta-analysis was performed to assess the effectiveness and safety of adjuvant intraoperative hyperthermic intraperitoneal chemotherapy (IHIC) for patients with resectable locally advanced gastric cancer, and to provide the reference for clinical practice and study.

Methods: We searched the Cochrane Library, PubMed, Embase, Web of Science and Chinese databases (Chinese BioMedical Literature Database (CBM), China National Knowledge Infrastructure (CNKI) and Wanfang) electronically and also retrieved papers from other sources (tracing related references and communication with other authors). All relevant randomised controlled trials (RCTs) were collected to compare surgery combined with IHIC to surgery without IHIC for AGC. There were no language restrictions. After independent quality assessment and data extraction by two reviewers, meta-analysis was conducted by RevMan 5.1 software.

Results: 16 RCTs involving 1,906 patients were included. Compared with surgery alone, combination therapy (surgery plus IHIC) was associated with a significant improvement in survival rate at 1 year (hazard ratio (HR) = 2.99; 95% confidence interval (CI) = 2.21 to 4.05; p < 0.00001), 2 years (HR = 2.43; 95%CI = 1.81 to 3.26; p < 0.00001), 3 years (HR = 2.63; 95%CI = 2.17 to 3.20; p < 0.00001), 5 years (HR = 2.49; 95%CI = 1.97 to 3.14; p < 0.00001), and 9 years (HR = 2.14; 95%CI = 1.38 to 3.32; p = 0.0007). Compared with surgery alone, combination therapy was associated with a significant reduction in recurrence rate at 2 years (RR = 0.42; 95%CI = 0.29 to 0.61; p < 0.00001), 3 years (RR = 0.35; 95%CI = 0.24 to 0.51; p < 0.00001) and 5 years (RR = 0.47; 95%CI = 0.39 to 0.56; p < 0.00001). IHIC was not found to be associated with higher risks of anastomotic leakage, ileus, bowel perforation, myelosuppression, gastrointestinal reaction and hypohepatia, but it increased the incidence of abdominal pain (RR = 21.46; 95%CI = 5.24 to 87.78; p < 0.00001).

Conclusions: Compared with surgery alone, surgery combined with IHIC can improve survival rate and reduce the recurrence rate, with acceptable safety. However, safety outcomes should be further evaluated by larger samples and high quality studies. Additionally, hyperthermia for the intraperitoneal chemotherapy needs more clinical research.