Image-guided brachytherapy for locally advanced cervical cancer: clinical outcomes and fistula risk in stage IVA...

To report outcomes for patients with locally advanced cervical cancer, with a focus on stage IVA disease, and to explore factors associated with fistula formation.

Clinical data from patients with cervical cancer treated with primary chemoradiotherapy and magnetic resonance imaging-guided brachytherapy were retrospectively reviewed. Oncologic outcomes (overall survival, disease-free survival, and central failure) were assessed using Kaplan-Meier, Cox regression, and competing-risk analyses. Logistic regression was used to assess factors associated with any fistula and late-occurring fistula.

A total of 151 patients had a median follow-up of 2.9 years; 22/151 (14.6%) had stage IVA disease. Compared with stages I to III, stage IVA disease was associated with worse disease-free survival (hazard ratio 2.79, 95% confidence interval 1.59 to 4.91, p < .001) and overall survival (hazard ratio 4.81, 95% confidence interval 2.48 to 9.32, p < .001), but not with central failure (hazard ratio 1.28, 95% confidence interval 0.36 to 4.63, p = .7). HR-CTV D90 is the minimum radiation dose (in Gy) delivered to 90% of the high-risk clinical target volume did not differ significantly by stage, although bladder and rectum D2cc doses were higher in patients stage IVA due to organ invasion. Multivariable analysis identified prognostic factors for any fistula of body mass index <20 kg/m² with an odds ratio 4.33 (1.11 to 16.90, p = .035), immune-compromised status odds ratio 5.84 (1.32 to 25.91, p = .020), stage IVA disease odds ratio 6.87 (1.99 to 23.75, p = .002), and larger primary tumor volume odds ratio 3.29 (1.53 to 7.08, p = .002). The only significant factors for oncologic outcomes were: for disease free survival, race (hazard ratio 0.57, 95% confidence interval 0.33 to 1, p = .05); for overall survival, stage IVA disease (hazard ratio 3.43, 95% confidence interval 1.67 to 7.06, p < .01); and for central failure, treatment duration > 56 days (hazard ratio 1.03, 95% confidence interval 1.002 to 1.06, p = .037). The 3-year cumulative incidence of central failure did not differ between stages I to III (10.2%) and IVA (14.3%) (p = .7).

Patients with stage IVA disease have worse disease-free survival and overall survival, but not central failure, compared to patients with stages I to III disease. Magnetic resonance imaging-guided brachytherapy results in a low incidence of central failure across stages. Several comorbidities and disease-related factors impact the risk of fistula formation.