Objective: To evaluate the difference in operative and clinical outcome for patients with primary advanced ovarian cancer (AOC) after optimal primary debulking surgery (PDS) versus interval debulking surgery (IDS).

Methods: Tumor dissemination pattern and surgical outcome, as defined by morbidity, progression-free (PFS) survival and overall survival (OS) were systematically analyzed in AOC patients who underwent surgery in our institution between September 2000 and August 2009. Overall survival and PFS were calculated by Kaplan-Meier curves. Univariate and Cox regression analysis were performed to identify the impact of IDS on surgical outcome and survival.

Results: Overall, 372 consecutive patients with histologically proven AOC (FIGO [International Federation of Gynecology and Obstetrics] stage III/IV) were evaluated. Forty patients (10.8%) underwent IDS after a median of 5 cycles (range, 2-6 cycles) platinum- and taxane-based chemotherapy, and 332 patients (89.2%) underwent PDS. Patients who underwent IDS had a significantly lower rate of tumor involvement of the lower (78.9% vs 98.8%; P < 0.001) and middle abdomen (68.4% vs 83.1%; P = 0.044) compared with PDS patients. During IDS, a significantly higher probability for complete tumor resection occurred when compared with PDS (85% vs 58.7%; P = 0.02) by equivalent rates of operative complications (36.4% vs 36.5%; P = 1.00). However, mean PFS was significantly reduced in IDS patients (14.6 vs 33.2 months; P < 0.001). Mean OS was also higher in PDS patients, but this reached a statistical significance only when complete tumor resection was obtained (65.4 vs 37.9 months; P = 0.005). Multivariate analysis identified that IDS was associated with an unfavorable OS and PFS.

Conclusions: It seems that PDS has a more favorable outcome than IDS on both OS and PFS in AOC patients, even though IDS leads to significantly higher rates of complete tumor resection.