Clinical Outcomes of Patients with FIGO Stage IVB Gynecologic Malignancies Treated with Aggressive Radiotherapy

Abstract

<h3>Purpose/Objective(s)</h3> Therapeutic options for patients with FIGO stage IVB gynecologic malignancies (GM) are limited. While systemic therapy is the mainstay of treatment, radiotherapy (RT) can play a role. Traditionally, RT has utilized lower doses with a goal of symptom control. However, escalated doses of RT with definitive doses may maximize symptomatic palliation, long term disease control and overall survival (OS). The primary aim of this study is to examine our experience treating FIGO stage IVB GM with escalated doses of RT (external beam radiotherapy, EBRT +/- brachytherapy, BT). <h3>Materials/Methods</h3> Patients with FIGO stage IVB GM treated with RT at a tertiary medical center between 01/2013 and 12/31/21 were retrospectively reviewed. Patients treated with traditional palliative doses (≤30Gy or "quad shot") and those who did not receive RT to the pelvis were excluded. Acute toxicity was defined as occurring ≤30d of RT completion. Demographic and clinical traits were summarized by descriptive statistics. Discrete variables were summarized by frequencies and percentages and continuous variables were summarized by mean, median, and standard deviation. OS and PFS were assessed by Kaplan-Meier method. Bivariate associations were assessed through Spearman's correlation test. Statistics were run using statistical software. <h3>Results</h3> 22 patients met criteria for inclusion, 11 with endometrial, 8 with cervical and 3 with vaginal/vulvar cancer. Median age was 58. Adenocarcinoma was the most common histology (55%). The most common locations of metastatic disease were distant lymph node (23%), bone (23%) and lung (23%). 77% of patients had more than one site of metastatic disease. 13 patients had systemic therapy and 9 had surgery prior to RT. All patients started EBRT, with most common planned fractionation of 45 Gy in 25 fractions. 18 patients (81.8%) completed their prescribed course of EBRT. Only 1 patient discontinued RT due to disease progression. 11 patients completed BT, most commonly (18.2%) with a vaginal cylinder. Only 2 patients (9.1%) experienced a grade 3 (G3) toxicity: 1 dermatitis and 1 fistula. Grade 2 (G2) acute toxicities include: 5% cystitis, 36% proctitis, 5% vaginal stenosis, 14% dermatitis/mucositis, 14% vaginal pain and 23% nausea. G2 late toxicities include: 5% cystitis, 5% proctitis and 5% vaginal pain. At mean follow up of 26.5 months, 40.9% of patients were deceased. 11 patients (50%) experienced disease recurrence/progression, most commonly outside of the RT field (63.6%). Four patients (18.2%) experienced local progression/recurrence. Median time to recurrence/progression was 18.0 months (95% CI 0-49.5). Median OS was 45.0 months (95% CI 15.4-74.6). <h3>Conclusion</h3> Escalated doses of RT for patients with FIGO IVB GM has tolerable acute and late toxicities while providing meaningful locoregional control. This warrants additional investigation into this treatment regimen.