Ovarian cancer is the most common cause of death in gynecological cancer. Approximately 75% of epithelial ovarian cancers are detected at an advanced stage. Metastasis and spread are mostly through transperitoneal planting and neighborhood by shedding from the ovarian surface. Metastasis mostly occurs in the peritoneum, omentum, and intestines. The rectosigmoid colon is the main part of the intestine affected by metastasis due to its neighborhood.

Treatment in ovarian cancer consists of a combination of cytoreduction surgery and platinum-based chemotherapy. Surgery is the basis of the treatment, and the main goal is to achieve no residual visible tumor (complete cytoreduction: R0). The residual tumor is one of the main factors affecting survival and reflects the possibilities of the surgical center and the team. Multiple surgical procedures (total hysterectomy, bilateral salpingo-oophorectomy, total omentectomy, peritonectomy, retroperitoneal lymphadenectomies such as pelvic and paraaortic, bowel resections, splenectomy, distal pancreatectomy, various resections related to the bladder, liver, stomach, and diaphragm) may be required to achieve complete or optimal cytoreduction.

In the involvement of the rectosigmoid colon, primarily the serosa, then the muscular layer and finally the mucosa are infiltrated due to the nature of the spread, and therefore most of the involvement is observed in the seromuscular layer. In seromuscular infiltration, resection of the rectosigmoid colon or shaving of tumoral implants without resection can be performed. There are advantages and disadvantages of each method in terms of morbidity. Although there are retrospective studies evaluating recurrence and survival between both methods, as far as investigators know, no randomized prospective studies have been conducted comparing these two methods. The investigators designed this study to compare these two methods successfully applied in our clinic in a prospective randomized study.

Inclusion Criteria:

• Epithelial ovarian cancer
• Negative colonoscopy ( no mucosal involvement)
• Intraoperative confirmed serosal or seromuscular rectosigmoid infiltration
• ECOG <3
• ASA <3

Exclusion Criteria:

• Nonepithelial ovarian cancers
• Rectosigmoid mucosal infiltration
• Total or subtotal colectomy necessitating large bowel infiltrations
• ECOG >2
• ASA >2