Objectives: The aim of the study was to investigate the correlation of chemotherapy response score (CRS) after neoadjuvant chemotherapy (NACT) to treatment outcomes in ovarian cancer (OC).
Methods: Chemotherapy response score was retrospectively determined on pathology slides of all patients with epithelial OC that had interval debulking surgery (IDS) between 2009-2014. Chemotherapy response score 1 was given when tumor was present and infiltrated by inflammatory cells, CRS 2 when both tumor and regressive chemotherapy changes were present, and CRS 3 when scant tumor was seen within extensive chemotherapy-induced changes. Patients' characteristics including survival data were collected and compared between CRS groups.
Results: Pathology slides of 132 patients were reviewed. Forty-nine patients had CRS 1, 65 had CRS 2, and 18 had CRS 3. Age, stage, and grade were not different across CRS groups. A higher percent of CRS 1 and 2 patients required more than 3 cycles of NACT, whereas CRS 3 patients had higher rates of no residual disease at completion of IDS. Chemotherapy response score 3 group showed the most significant CA125 decrease after NACT (97% decrease, P = 0.016). Kaplan-Meir survival curves showed a significantly longer progression-free survival but not overall survival for patients with CRS 3 (median progression-free survival = 7.5, 12, and 17 months for CRS 1, 2, and 3, respectively, P = 0.012), and this remained statistically significant in both univariate and multivariate analysis. Interobserver reproducibility for CRS was good (weighed κ = 0.762).
Conclusions: Patients with CRS 3 have longest progression-free survival and highest CA125 drop after NACT. These parameters have important prognostic value and can be used for clinical decision-making.