To assess the efficacy of systematic pelvic and para-aortic lymphadenectomy in patients with advanced ovarian cancer and intra-abdominal complete debulking.

Secondary: progression-free survival, complications and quality of life; Exploratory: Role of number of resected lymph nodes for primary and secondary objectives

Inclusion Criteria:

• Primary diagnosis of invasive epithelial ovarian cancer FIGO stage IIB-IV (IV only if resectable metastasis in pleura, liver, spleen, and/or abdominal wall)
• Macroscopic complete resection
• Age: 18 - 75 years
• Patients who have given their signed and written informed consent
• Good performance status (ECOG 0/1)

Exclusion Criteria:

• Non epithelial ovarian malignancies and borderline tumors
• Intraoperative clinically suspicious lymph nodes (bulky nodes)
• Secondary invasive neoplasms in the last 5 years (except synchronal endometrial carcinoma FIGO IA G1/2, non melanoma skin cancer, breast cancer T1 N0 M0 G1/2) or with any signs of relapse or activity.
• Recurrent ovarian cancer
• Prior chemotherapy for ovarian cancer or abdominal/pelvic radiotherapy
• Diseases of the lymph system (including lymph edema of unknown origin)
• Clinical relevant dysfunctions of blood clotting (including medicamentous conditioned reasons, e.g. ASS, if not stopped at least 7 days prior to surgery)
• Any significant medical reasons, age or performance status that will not allow to perform the study procedures (estimation of investigator)
• Prior retroperitoneal lymph node dissection (systematic or sampling)
• Pregnancy
• Dementia or significantly altered mental status that would prohibit the understanding and giving of informed consent
• Any reasons interfering with regular follow-up