Single Institution Experience of the Effect of Adjuvant Radiation on Outcomes for Patients with Uterine Carcinosarcoma

Abstract

Uterine carcinosarcoma (UCS) is a rare but aggressive malignancy with poor outcomes. Due to its low incidence, there is no well-established optimal treatment. Standard treatment involves surgery and chemotherapy (CT) +/- adjuvant radiation therapy (RT). Our primary aim was to determine if patients who underwent adjuvant RT had improved distant metastasis free survival (DMFS) and locoregional recurrence free survival (LRRFS). Our secondary aim was to determine the effect of adjuvant RT on overall survival (OS). We performed a single institutional retrospective review of all patients with UCS who underwent primary surgical resection +/- CT and +/- RT between 2007 to 2021. Patients without at least 3 months of documented follow-up were excluded. We assessed DMFS, LRRFS, and OS between patients who did and did not receive adjuvant RT, consisting of vaginal brachytherapy (VBT), external beam radiation therapy (EBRT), or EBRT + VBT. Statistical analysis was performed with spreadsheet and statistical software. Sixty-four patients underwent primary surgical resection for FIGO stage I-IV UCS. Sixty six percent (n = 42) had early stage, FIGO I-II disease and 34% (n = 22) had late stage, FIGO III-IV disease. Eleven percent (n = 7) underwent surgery alone, 28% (n = 18) underwent surgery + CT, 6% (n = 4) underwent surgery + adjuvant RT, and 55% (n = 35) underwent surgery + CT + RT. Most patients who underwent surgery + CT + EBRT + VBT (n = 9) had worse clinicopathologic features including late stage (56%), lymphovascular invasion positive (78%) disease with 50% or greater myometrial invasion (56%). EBRT doses ranged from 45-50.4 Gray (Gy) in 1.8 Gy per fraction. VBT doses ranged from 21-25 Gy in 3-5 fractions when delivered alone and 10-15 Gy in 2-3 fractions when delivered as a boost. Median DMFS was 20.3 months, median LRRFS was 22.6 months, median DFS was 19.4 months, and median OS was 24.7 months. Rate of distant metastasis appeared to drive rate of disease-free survival (Table 1). Patients who underwent adjuvant RT had improved median DMFS (71.5 vs. 11.3 months, p = .002), median LRRFS (71.5 vs 22.5 months, p = .002), and median OS (60.7 vs. 22.5 months, p = .002) compared to those who did not receive RT. Prognosis of patients with UCS remains poor; however, adjuvant RT delivered after CT may offer potential benefit in survival outcomes despite worse clinicopathologic features in these patients.