MRI-based low dose-rate brachytherapy experience in locally advanced cervical cancer patients initially treated by concomitant chemoradiotherapy

PurposeTo retrospectively assess the physics contributions and the clinical outcome with preliminary 3D MRI-guided low dose-rate (LDR) intracavitary brachytherapy (BT) experience in locally advanced cervical cancer patients.Patients and methodsEighty-four patients with primary locally advanced cervical carcinoma were analyzed. The median tumoral cervical volume was 48.0 cc (range 1–468 cc). Twenty-four patients (53%) had histological and/or radiological pelvic involvement. After pelvic ± paraaortic concomitant chemoradiation, a LDR BT boost was delivered to a 3D MRI-based clinical target volume taking into account dose volume constraints for critical organs and optimization of target volume coverage.ResultsWith a median follow-up of 53 months (range 31–79 months), the 4-year overall survival and disease-free survival rates were 57 (95%CI, 43–69) and 52% (95%CI, 40–64), respectively. Adding EBRT and LDR using EQD2 model, the median D100 and D90 for the IR-CTV were 56.5 Gyα/β10 (range 37–83 Gyα/β10) and 69 Gyα/β10 (range 52–113 Gyα/β10), respectively. For HR-CTV, the median D100 and D90 were 67 Gyα/β10 (range 47–119 Gyα/β10) and 79 Gyα/β10 (range 53–122 Gyα/β10), respectively. Thirty-nine late complications were observed in 28 patients (33.3%): 13 bladder, 7 rectal, 5 small bowel, 4 urethral, 3 colic, 2 vaginal, 1 pelvic fibrosis, and 4 others. Four grade 3 delayed complications were observed and no grade 4 complication occurred.ConclusionsApplying an individual treatment planning with 3D MRI-guided LDR brachytherapy appears to be feasible and efficient for patients with locally advanced cervical cancer in routine clinical practice.