Study parameters: Regarding feasibility and safety, endpoints of the phase II study are the number of randomised patients 1 year after the start of accrual at the last participating centre, major postoperative complications (Clavien-Dindo grade III-V) at 3 months postoperatively, and the number of patients receiving CRS + HIPEC. Secondary endpoints are minor postoperative complications (Clavien-Dindo grade II) and systemic therapy related toxicity (NCICTCAE v4.0 Grade II-V). The phase II study is deemed unfeasible if <80 patients are randomised, and deemed unsafe if: