Patterns of Recurrence After Adjuvant Vaginal Cuff Brachytherapy and Chemotherapy in Early-Stage Uterine Serous Carcinoma

Purpose/Objective(s): Adjuvant vaginal cuff brachytherapy (VB) and chemotherapy are commonly utilized in women with early-stage uterine serous carcinoma (USC). We sought to characterize predictors of survival endpoints and recurrence patterns in this rare population who received similar adjuvant treatments. Materials/Methods: We queried our prospectively maintained database for patients with 2009 FIGO stages I-II USC who underwent adequate surgical staging at our institution and received adjuvant chemotherapy with carboplatin and paclitaxel along with VB. We excluded women with synchronous malignancies. Overall survival (OS), disease-specific survival (DSS), and recurrence-free survival (RFS) were assessed by Kaplan-Meier and log-rank tests. Univariate (UVA) and multivariate analyses (MVA) were performed to identify statistically significant predictors of survival endpoints. Variables with P \u3c 0.1 on UVA were included in a MVA and any variable with P \u3c 0.05 was considered statistically significant. Results: We identified 77 women who met our inclusion criteria who underwent surgical staging between 1991 and 2018. The median follow-up time was 36 months (range 6-125). The median age was 66 years. Of the cohort, 70% were FIGO stage IA, 17% were stage IB, and 13% were stage II. The median number of dissected lymph nodes was 22. There were 10 women (13%) diagnosed with a recurrence with a median time to recurrence of 12.0 months. The main site of initial recurrence was distant in seven patients (70%). For the entire cohort, 5-year OS, DSS, and RFS were 83% (95% Confidence Interval [CI] 0.68-0.91), 92% (95% CI 0.78-0.97), and 83% (95% CI 0.71-0.91), respectively. The sole independent predictor of 5-year DSS was the presence of positive peritoneal cytology (Hazard Ratio 0.03, 95% CI 0.00-0.72, P = 0.03). Conclusion: Although 5-year survival outcomes were promising in this cohort, this study suggests that the predominant pattern of relapse in early-stage USC treated with adjuvant chemotherapy and VB is distant, calling for the optimization of systemic therapy. Positive peritoneal cytology is an independent predictor of worse DSS. Multi-institutional pooled analyses are warranted to confirm our study results