Forty-seven studies were included (n=3,941): two RCTs (n=140); two comparative studies (n=114); and 43 observational studies (n=3,687).
One RCT reported adequate concealed methods of stratified randomisation, baseline comparability of treatment groups and analysis on an intention-to-treat basis. The other RCT failed to recruit the intended number of patients and treatment groups appeared non-comparable at baseline.
Cytoreductive surgery in combination with perioperative intraperitoneal chemotherapy was associated with a statistically significant improvement in survival compared with control (HR 0.55, 95% CI 0.40 to 0.75; four studies, n=271).
Cytoreductive surgery in combination with hyperthermic perioperative intraperitoneal chemotherapy was associated with a statistically significant improvement in survival compared with palliative care (HR 0.47, 95% CI 0.32 to 0.69; two studies, n=201).
There was no statistically significant difference in survival between cytoreductive surgery plus early postoperative intraperitoneal chemotherapy plus systemic chemotherapy compared to surgery plus systemic chemotherapy (two studies, n=70). There was no significant heterogeneity for any analysis.
Overall median survival ranged from 11.9 to 60.1 months. Median survival rates were 76% at one year, 55% at two years, 36% at three years, 28% at four years and 19% at five years. Perioperative morbidity rates ranged from 14.8% to 76% and perioperative mortality ranged from 0% to 12%. Average duration of hospital stay ranged from nine to 29 days.