Comparative effectiveness of paclitaxel versus cyclophosphamide in platinum-based adjuvant treatment of high-risk early-stage epithelial ovarian cancer: an Asian population study

In Taiwan, approximately half of ovarian cancer cases are diagnosed at an early stage. Although platinum-based adjuvant chemotherapy is recommended for high-risk early-stage epithelial ovarian cancer (EOC), the optimal regimen remains uncertain. Paclitaxel (PTX) is widely used based on evidence from advanced-stage disease, yet data comparing PTX and cyclophosphamide (CTX) in early-stage settings are limited. We retrospectively reviewed medical records of FIGO stage I-II EOC patients with high-risk features who received post-operative platinum-based chemotherapy with either PTX or CTX at Kaohsiung Chang Gung Memorial Hospital from January 2011 to December 2018. We analyzed associations between clinical characteristics, chemotherapy regimen, and survival outcomes. Baseline characteristics were compared using Chi-square tests for categorical variables and independent two-sample t-tests for continuous variables. Survival analysis was conducted using Kaplan-Meier and Cox regression methods. A total of 125 patients were included (mean age: 50.0 years), of whom 27.2%, 48.8%, and 24.0% were diagnosed with FIGO stage IA/IB, IC, and II, respectively. Clear cell (37.6%) and endometrioid (27.2%) carcinomas were the most common histologies. Eighty-one patients (64.8%) received PTX, and 44 (35.2%) received CTX. Multivariate analysis identified FIGO stage as the only independent predictor of disease-free survival (DFS; HR, 3.39; <i>P</i> = 0.046), while the chemotherapy regimen was not significantly associated with DFS (HR 2.58; <i>P</i> = 0.111). Since stage I patients constituted the majority of the cohort, we performed a subgroup analysis restricted to stage I patients, which similarly demonstrated no significant DFS difference between the two chemotherapy regimens (<i>P</i> = 0.377). CTX demonstrated comparable DFS outcomes to PTX in high-risk early-stage EOC. These findings support the use of CTX as a viable adjuvant chemotherapy alternative to PTX, particularly in Asian populations where clear cell and endometrioid histologies are more prevalent.