Session Item

Current literature on single application multifractionated brachytherapy(BRT) is limited. The use of MRI, which provides better soft-tissue delineation, allows more hypofractionated treatment, with a recent study showing acceptable results using three fractions. However, with CT- based treatment, the most commonly used regimen consists of 5-6 fractions with concerns of toxicity if a more hypofractionated regimen was used. The aim of the study is to evaluate the safety and clinical outcomes of single application multifractionated CT-guided interstitial high-dose-rate(HDR) BRT given in four fractions in locally advanced cervical cancer.

Patients with cervical cancer FIGO 2018 stage IIB-IVA that were treated definitively with external radiation (50Gy/25fractions) ± weekly cisplatin followed by single application multifractionated CT-guided interstitial HDR BRT were included. The protocol involves the use of four fractions of HDR BRT given in 3 consecutive days with 2 fractions given on the second day 6 hours apart with a total planning target of HRCTVD90 of >85Gy EQD2. Dosimetric data, clinical response, and toxicity records were reviewed.

Twenty-three consecutive patients were included. Clinical stage distribution was as follows: IIB: 13.0% (3), IIIB: 26.1% (6), IIIC: 26.1% (6) and IVA: 34.78% (8). Median initial T score at diagnosis was 10 (range 7-15). All patients underwent Intracavitary + Interstitial BT with needles (median 11 ; range, 6-20). The mean ± standard deviation HRCTV volume was 67.88 ± 27.66 cm3 and HRCTV D90 dose was 83± 10.8Gy. The 2 cm3 to bladder, rectum, and sigmoid were 86.37 ± 7.5 Gy, 72.60 ± 6.0 Gy, and 68.18 ± 8.3 Gy, respectively. Mean overall treatment time was 65 ± 21 days. With a median follow up of 9.5 months (range, 1-39), The median survival was 16 months, and the one-year local control rate, progression free survival and overall survival were 73% (54-100, 95% CI), 60% (40-92, 95% CI), and 72% (52-100, 95% CI), respectively. For the acute toxicity, grade 3 radiation-related toxicity was observed in 4 patients: 1 hematologic, 1 diarrhea, and 2 infections. The most severe was one patient with grade 4 toxicity of sepsis. For the late toxicity, grade 3 toxicity was observed in 3 patients: 2 proctitis needing intervention and 1 genitourinary toxicity. There were 3 grade 4 genitourinary toxicity with one needing a nephrostomy tube, and two requiring dialysis.

Single application multifractionated CT-Guided Interstitial HDR BRT given in four fractions in locally advanced cervical cancer is feasible and safe showing satisfactory response and acceptable toxicities.