DVH parameters and outcome for patients with early-stage cervical cancer treated with preoperative MRI-based low dose rate brachytherapy followed by surgery

Background: To our knowledge no DVH data have so far been reported for MRI-guided BT in the preoperative setting of early-stage cervical cancer. We assessed DVH parameters and clinical outcome using 3D MRI-guided preoperative intracavitary LDR BT. Patients and methods: Thirty-nine patients with primary early cervical carcinoma (IB1 37, IIA 1 and IIB 1) were treated with preoperative MRI-based LDR BT, consisting of uterovaginal BT to a total dose of 60 Gy to the intermediate-risk CTV, followed 6 weeks later by bilateral salpingo-oophorectomy and extrafascial hysterectomy plus pelvic node dissection. Adjuvant chemoradiation was delivered to patients with pelvic lymph node involvement. Results: With a median follow-up of 4.4 years (range 2.6-6.6 years), local recurrence occurred in 1 patient (a lateropelvic relapse) (2.6%). The 4-year actuarial overall survival and disease-free survival were 94% (95% CI, 82-98), and 86% (95% CI, 67-95), respectively. The 2- and 4-year actuarial local relapse-free survival were 94 (95% CI, 86-100) and 91% (95% CI, 81-100), respectively. For intermediate-risk CTV, median D₁₀₀ and D₉₀ were 43 Gy_α/β10 (range 2-74 Gy_α/β10) and 75 Gy_α/β10, respectively (range 29-129 Gy_α/β10). For high-risk CTV, the median D₁₀₀ and D₉₀ were 69 Gy_α/β10 (range 24-137 Gy_α/β10) and 109 Gy_α/β10 (range 37-198 Gy_α/β10), respectively. Twenty grade 1-2 late complications were observed in 13 patients (33.3%): 10 bladder, 3 ureteral, 1 rectal, 1 small bowel, 1 vaginal, 1 pelvic fibrosis, 1 peripheral nerve, and 2 others. No grade 3 or 4 complication occurred. Conclusion: MRI-guided brachytherapy with adaptation of the time duration and/or the length of each radioactive source allows both high local control and low toxicity in the preoperative settings of early-stage cervical cancers.