Cytoreductive surgery (CRS) with the addition of hyperthermic intraperitoneal chemotherapy (HIPEC) is used in current clinical practice in selected patients with advanced ovarian cancer. Clinical evidence for the benefit of HIPEC in ovarian cancer comes from the pivotal phase 3 OVHIPEC trial. Worldwide, two established strategies exist for dosing of HIPEC protocols, which follow either a body surface area (BSA)-based or a concentration-based approach. Since both strategies result in different exposure to intra-peritoneal chemotherapy, we aim to compare the pharmacokinetics and safety of both strategies.

Inclusion Criteria:

1. signed and written informed consent

2. age ≥ 18 years

3. patients eligible for interval cytoreductive surgery

   1. histological proven FIGO stage III primary high grade serous ovarian, fallopian tube, or extra-ovarian cancer
   2. when only cytology is performed to confirm the diagnosis ovarian carcinoma, immunohistochemistry should be performed including keratin 7, keratin 20, p53, PAX8
   3. neo-adjuvant chemotherapy consists of (at least) 3 courses of carboplatin/paclitaxel
   4. following 2 cycles of chemotherapy no progression should occur

4. treated with optimal or complete interval cytoreductive surgery

5. fit for major surgery, WHO performance status 0-2

6. adequate bone marrow function (hemoglobin level >5.5 mmol/L; leukocytes >3 x 109/L; platelets >100 x 109 /L)

7. adequate hepatic function (ALT, AST and bilirubin <2.5 times upper limit of normal)

8. adequate renal function (creatinine clearance ≥ 60 ml/min using Cockcroft-Gault formula or 24-hour measurement or ml/min/1,73 m2 using MDRD or CKD-EPI)

9. able to understand the patient information

Exclusion Criteria:

1. history of previous malignancy treated with chemotherapy
2. opting for fertility-sparing surgery