Pattern of pelvic recurrence in MRI-only adaptive brachytherapy for locally advanced cervical cancer.

Purpose: MRI-only adaptive brachytherapy (MRI-ABT) is the state-of-the-art for treating locally advanced cervical cancer (LACC) in combination with concurrent chemoradiotherapy. We aimed to evaluate the pattern of pelvic recurrence after the treatment.

Material and methods: A total of one hundred LACC patients were treated between January 2017 and December 2023 with concurrent chemoradiotherapy of 45 Gy in 25 fractions ± boost to lymphadenopathy (up to a maximum dose of 60 Gy in 25 fractions) with concurrent weekly cisplatin chemotherapy at the dose of 40 mg/m²/week, and MR-ABT.

Results: At a median follow-up of 30.2 months, there were 2 local recurrences (2%) and 9 regional pelvic recurrences (9%). The median time to local/regional recurrence was 11 months (range 6-21). For all stages, the 3-year local control was 97.66%, and the 3-year pelvic control was 89.45%. Twenty-four patients died during follow-up; the 3-year overall survival was 75.11%, and the 3-year disease-free survival was 70.97%.

Conclusion: MRI-ABT combined with external beam radiotherapy and concurrent chemotherapy for LACC demonstrates excellent local and regional pelvic control. Most local/regional recurrences occur inside or at the edge of the external-beam irradiated field. Recurrences inside the field of brachytherapy are rare. Distant recurrences are the predominant cause of death in LACC patients treated with definitive CRT and MRI-ABT.