The objective of the cytoreductive surgery carried out for the management of ovarian cancers is to obtain a complete macroscopic cytoreduction. This means that all visible peritoneal metastases must be resected. The peritoneum is the most frequent site of recurrence after initial management. There is no data on the existence, prevalence of microscopic peritoneal metastases. It nevertheless represents a therapeutic target (intraperitoneal chemotherapy). The main objective is the demonstration of microscopic peritoneal metastases in macroscopically healthy peritoneum after complete macroscopic cytoreductive surgery.

Understanding biology and progression mechanisms of peritoneal metastases (PM) of epithelial ovarian cancer (EOC) is a cornerstone in the knowledge and the comprehensive management of the disease, as PM will occur in the majority of patients. Indeed, the goal of cytoreductive surgery (CRS) in these patients is to completely remove all visible peritoneal invasion because the absence of residual disease after surgery is known to improve the prognosis.

Despite clinical remission after the completion of complete surgery and platinum-based chemotherapy, 60% of patient develop peritoneal recurrence. This suggests that microscopic lesions may be present that are not eradicated by surgery, not controlled by systemic chemotherapy and that may be one of the mechanisms leading to peritoneal recurrence. Peritoneal carcinomatosis is responsible for the greatest morbidity and mortality in women with EOC.

There are very few studies in the literature on microscopic peritoneal involvement in EOC, its detection and potential role in the progression of cancer. The peritoneum should be considered an organ in its own right and the surgeon must treat peritoneal metastases with the intent to cure. To follow the recommendations, this microscopic disease must be managed, because complete CRS is now a skill that can be mastered skill and its uses is a validated guideline. Moreover, "complete CRS" should be defined as "without macroscopic residual disease" thus highlighting the presence of microscopic disease.

The goal of this study is to add scientific evidence for the existence of Microscopic Peritoneal Metastases (mPM) and to justify the need for additional diagnostic and therapeutic approaches.

Inclusion Criteria:

• Age > 18 years-old, French nationality
• with epithelial ovarian or tubal cancer
• Complete macroscopic cytoreductive surgery (CC-0) regardless of the sequence compared to chemotherapy.
• Patient giving express consent

Exclusion Criteria:

• Borderline ovarian tumor
• Incomplete cytoreductive surgery
• Pregnant women
• Major under guardianship / trusteeship,
• Not insured