Sample size: The phase II study includes 80 patients, with 40 patients in each arm. After fulfilling the criteria of feasibility and safety criteria, the study continues as a phase III superiority study with 3 year overall survival as primary endpoint. The expected 3-year overall survival after CRS + HIPEC is 50%. We hypothesize that the experimental treatment results in a 15% increase in overall survival rate if analysed according to an intention-to-treat principle. With a 0.05 two-sided significance level, 80% power and a drop-out of 5%, a sample size of 179 patients in each arm is needed, resulting in a total of 358 patients, including the 80 patients from the phase II study.