Early-stage uterine papillary serous carcinoma: Clinical outcomes in patients treated with adjuvant chemotherapy and vaginal brachytherapy

Objective: There are limited data on optimal adjuvant therapy for early-stage uterine papillary serous carcinoma (UPSC). Treatment practices range from chemotherapy alone to chemotherapy with or without vaginal brachytherapy (VBT) and/or external beam radiation therapy. We report our experience treating early-stage UPSC with adjuvant chemotherapy and VBT. Methods: We performed a retrospective study on patients diagnosed with uterine-confined UPSC from 2009 to 2023. We assessed clinical characteristics, treatment parameters, and disease outcomes. Kaplan-Meier method and log-rank test were used for evaluating recurrence-free survival (RFS). Cox proportional hazards modeling was used for univariable and multivariable analysis. Results: We identified 74 patients with uterine-confined UPSC. Distribution by FIGO stage 2009 was as follows: stage: IA 60 (81.1 %), IB 14 (18.9 %); according to FIGO 2023 stage: IC 21 (28.4 %), IIC 53 (71.6 %). The median follow-up was 38.4 months (interquartile range: 16.1 to 67.2 months). All patients received adjuvant carboplatin-based chemotherapy, generally with a taxane, and VBT. Fifteen patients (20.3 %) experienced a relapse with median time to recurrence of 20.4 months. Sites of relapse: 1 (1.4 %) local recurrence, 2 (2.7 %) isolated regional recurrences, 10 (13.5 %) distant relapses and 2 (2.7 %) both regional and distant relapses. Significant covariates for RFS on univariable analysis were FIGO 2023 stage (p = 0.037) and persistently abnormal CA-125 (p = 0.002), and these remained significant on multivariable analysis (p = 0.025 and p < 0.001, respectively). FIGO 2023 stage better prognosticated RFS (p = 0.05) than FIGO 2009 (p = 0.08). Conclusions: In a cohort of uterine-confined UPSC, use of the FIGO 2023 staging system is associated with improved outcome prediction, and adjuvant chemotherapy and VBT achieves excellent locoregional control. Most relapses are distant, suggesting a need for improved systemic therapy.