Cancer control and toxicity results of chemoradiation for cervical cancer using a three-fraction HDR brachytherapy boost.

Objective: Brachytherapy is essential for treating locally advanced cervical cancer, but many patients do not receive it due to the resource-intensive nature of the treatment. This study assessed cancer control and toxicity following an accelerated 3-fraction brachytherapy protocol.

Methods: We identified patients with cervical cancer who received high-dose-rate (HDR) brachytherapy in three fractions as part of chemoradiation at Kaiser Permanente Northern California from 2012-2020. Treatment details, oncologic outcomes and toxicity were determined retrospectively using available medical records. The primary outcome was local recurrence (LR). Secondary outcomes included disease-free survival (DFS), overall survival (OS), and grade ≥3 gastrointestinal (GI), urinary, and gynecologic toxicities.

Results: Among 199 patients (median age 52 years), 46.2% had Stage I-II and 53.8% had Stage III-IV disease. The median total radiotherapy duration was 50 days, with ≥5 cycles of cisplatin received by 86.9%. HDR brachytherapy (median dose 2400 cGy/3 fractions) was combined with EBRT, achieving D90% ≥8000 cGy (EQD2) to the high-risk clinical target volume in 92.6% of patients. At 2 years, LR was 5.6%, DFS 66.2%, and OS 80.2%, with lower DFS and OS in patients over 60 or with Stage III-IV disease (p < 0.001). Grade ≥3 toxicities occurred in 9.0% of patients, primarily GI (6.5% grade 3, 1.0% grade 4-5). Urinary and gynecologic grade three toxicities were 1.5% and 1.0%, respectively, with no grade 4-5 events.

Conclusions: A 3-fraction brachytherapy protocol demonstrated local control, DFS, and OS comparable to historical controls while maintaining high grade toxicity rates <10%. This approach reduces resource use and may improve treatment access for cervical cancer patients.