Non-brachytherapy approach for locally advanced cervical cancer treatment.

Abstract

e18023 Background: Concomitant chemoradiation therapy (CRT) that includes both external beam radiotherapy (EBRT) and brachytherapy (BT) is the current standard of care in treatment of locally advanced cervical cancer (LACC). Adaptive EBRT using volumetric modulated arc technology without BT allows dose escalation and decreases toxicities. Non-brachytherapy treatment is an evolving alternative approach provides geographical radiation accuracy but the oncological outcomes still to be evaluated. Methods: Patients with LACC (stages 1B3–IVA) who underwent non-brachytherapy CRT using adaptive EBRT with simultaneous integrated boost at our institution were evaluated prospectively from May 2015 to December 2019. All patients were initially assessed by a gynecologic oncologist, pelvic MRI and 18FDG-PET/CT scan were conducted. Follow-up pelvic examinations with cytology every 3 months and PET/CT at 3 and 12 months after completion of treatment were performed. Oncological outcomes and toxicities were assessed. Results: Twenty-one patients were analyzed: median age was 54 years (30–76 years); 19 patients had squamous cell histology and 2 had adenocarcinoma. Median follow-up was 32 months (8–56). The average dose administered to the gross tumor volume was 90.2 Gy (79.5–96.6), 79.8 Gy to all PET/MRI positive lymph nodes (63.0–89.7). No patents received BT; all but 3 received chemotherapy. Three-year local control was 100% (PFS = 90.4% and OS = 100%). There were 2 recurrences: a solitary skull lesion 18 months following CRT in a patient with mesonephric adenocarcinoma and a metastasis to a transposed ovary 15 months after CRT. No grade 3–4 toxicities were seen. Only 1 patient (4.7%) had late rectal grade II toxicity. Conclusions: Non-brachytherapy adaptive CRT for LACC is feasible. It allows for a significant dose escalation, thus providing better local control and likely increases PFS and OS at no cost of serious toxicity. Randomized studies comparing this approach to the current standard of care are needed.