Clinical analysis of pathologic complete responders in advanced-stage ovarian cancer

Objective: To determine the clinical characteristics of patients who attained pathologic complete response (pCR) after neoadjuvant chemotherapy (NACT) and to identify specific predictive or prognostic factors associated with pCR. Methods: Two distinct populations of patients who underwent NACT followed by interval tumor reductive surgery (TRS) were used in this retrospective study. The first contained 472 patients from a single institution. The second contained only pCR patients (67); those identified from population one, plus 44 obtained through collaborative institutions. Cox analysis and log-rank tests were performed to assess associations between clinical characteristics and pCR outcome, recurrence-free survival (RFS), and overall survival (OS). Results: The median RFS and OS in our pCR-only population was 24.2 and 80.8 months, respectively, with a median follow-up time of 32.4 months. In our single institution population, 23 patients attained pCR (4.9%) and had longer RFS compared to non-pCR patients with viable microscopic, optimal, or suboptimal residual disease (24.3 vs. 12.1 vs. 11.6 vs. 9.6 months, p = 0.025, 0.012, 0.008, respectively), and longer OS compared to those with optimal or suboptimal residual disease (54.5 vs. 29.4 vs. 25.7 months, p = 0.027, 0.007, respectively). Patients were more than three-fold likely to attain pCR if their CA125 value was normal at the time of surgery (OR 3.54, 95% CI: 1.14–11.05, p = 0.029). Conclusions: Women with pCR after NACT have significantly longer RFS compared to those with residual viable tumor at the time of interval tumor-reductive surgery, and CA125 is plausible biomarker for identifying these extreme responders preoperatively.