Monocentric Retrospective Study: Efficacy, Feasibility, and Prognostic Factors of Single-Insertion High-Dose-Rate Brachytherapy With 4 Sessions for Locally Advanced Cervical Cancer

Abstract

ObjectiveThis study aims to assess the feasibility and efficacy of high-dose-rate (HDR) brachytherapy (BT) administered in a single insertion with four treatment sessions for locally advanced cervical cancer (LACC), and to identify the prognostic factors influencing outcomes. MethodsWe retrospectively analyzed the clinical data of cervical cancer patients with locally advanced disease (International Federation of Gynecology and Obstetrics 2018 (FIGO) IB-IVB), treated at our institution from January 2014 through December 2021. Each patient received definitive radiotherapy with an external irradiation dosage between 45-50.4 Gy along with concurrent chemotherapy (CCRT). HDR-BT (24 Gy) was prescribed to a high-risk clinical target volume (HR-CTV). Results139 patients were included and HDR-BT program could be fully performed in 136 patients (98%). Over a median follow-up duration of 40.5 months, the two-year local control (LC), overall survival (OS), and disease-free survival (DFS) rates stood at 79.4%, 77.7%, and 61.7% respectively, with five-year rates at 78.2%, 61.6%, and 55.7%. Multivariate analysis revealed the primary determinant of LC as the tumor's response to external beam radiotherapy (EBRT) as determined via magnetic resonance imaging (MRI) prior to BT. Parametrial involvement demonstrated a significant multivariate association with DFS (p = 0.04). Regarding OS, parametrial invasion (p = 0.01) and the tumor's response post-chemoradiotherapy (p = 0.02) emerged as significant factors. Regarding chronic toxicities, 18% (25 patients) experienced grade 3 complications. An optimal D2cc (Bowel) threshold of 70 Gy (p = 0.001) was identified to limit chronic digestive complications of grade 3 or higher. ConclusionThe implementation of single-insertion, four-session HDR-BT could be performed in 98% of the patients. It yields favorable LC and OS rates, coupled with tolerable toxicity in patients with LACC. Response to initial chemoradiotherapy evaluated on pre-BT MRI is an important prognostic factor and could help to individualized therapeutic strategies.