Introduction/Background*Epithelial ovarian cancer (EOC) requires an aggressive surgical approach. The type and the number of procedures performed during primary (PDS) or interval (IDS) debulking surgery in order to achieve no residual disease are associated with considerable morbidities.

The objective is to describe a relationship among surgical complexity, early and late morbidities, and surgical timing in advanced EOC.

Methodology A retrospective study was performed at Leon Berard Cancer Center between 2006 and 2018. Surgical complexity was classified into three groups (standard, radical and ultra-radical surgery) based on the type and the number of procedures performed during PDS or IDS for advanced EOC. During the 30- and 90-day period after the surgery, the post-operative complications were registered according to the Clavien-Dindo classification.

Result(s)*311 patients with advanced EOC were included. 84 patients underwent PDS (27%) and 227 IDS (73%), respectively.

No residual disease was achieved in 258 out of 311 patients (83%). Standard surgery was performed in 80 patients (25.7%), radical surgery in 45 patients (14.5%) and ultra-radical surgery in 186 patients (59.8%). No residual disease was reached in 72 out of 80 standard surgery (90%), 37 out of 45 radical surgery (82.2%) and 149 out of 186 (80.1%) ultra-radical surgery.

Early and late severe (G3-4) complications were present in 32/311 patients (10.3%) and 23/311 patients (7.4%), respectively. Increased postoperative morbidity was directly related to the following perioperative factors: HIPEC [OR 4.4 (1.0-20)], addition of each single surgical procedures to the standard surgery [OR 1.3 (1.1-1.5)], number of surgical procedures added to modified pelvic posterior exenteration [OR 1.4 (1.1-2.0)], surgical complexity [SR vs S or R; OR 2.4 (1.1-5.7)].

In multivariate analysis, OS is not correlated with surgical complexity [OR 1.0(0.5-2.1)] and with the burden of early [OR 0.7(0.3-1.5)] or late [OR 0.7(0.3-1.7)] severe complications.

Conclusion*Despite surgical timing, ultra-radical-surgery is needed to reach no residual disease in >80% of our patients. The risk of early and late severe morbidities is increased for complex surgeries but they don’t affect OS. Risk stratification should be used to plan perioperative care and best treatment.