Long-term effectiveness and safety of image-based, transperineal combined intracavitary and interstitial brachytherapy in treatment of locally advanced cervical cancer

Abstract

PurposeThe aim of the study was to evaluate the impact of image-based combined intracavitary-interstitial brachytherapy (IC-ISBT) using a transperineal template in locally advanced cervical cancer treatment. Methods and MaterialsA total of 94 patients of cervical cancer stage IIB-IVA underwent image-based transperineal interstitial brachytherapy without tandem (ISBT) or with tandem (IC-ISBT) between June 2008 and June 2018 at our institution. After pelvic chemoradiation, 42 patients underwent ISBT and 52 IC-ISBT. Dosimetric data, clinical response, and toxicity records of these patients were reviewed. ResultsClinical stage distribution was as follows: IIB: 22.4% (21), IIIA: 10.6% (10), IIIB: 56.4% (53), and IVA: 10.6% (10). Mean high-risk clinical target volume was 75.72 cc, and mean cumulative equivalent of 2 Gy per fraction for high-risk clinical target volume was 81 Gy. The median followup was 35.5 months. Overall 3- and 5-year local control, disease-free survival (DFS), and overall survival (OS) were 84% and 84%, 69.1% and 62.9%, and 80.9% and 71.5%, respectively. Local control (90.4% vs. 76.2%; p = 0.048) and DFS (78.8% vs. 57.1%; p = 0.04) were significantly better in the patients of IC-ISBT arm. IC-ISBT (hazard ratio: 0.763; 95% confidence interval 0.217, 1.38; p = 0.046) and D90 dose >85 Gy (hazard ratio: 0.957; 95% confidence interval 0.927, 1.07; p = 0.037) were predictors of better DFS on univariate analysis. Overall survival was not affected significantly by any of the factors. Grade 3 and 4 late complications were recorded in 3.2% (3) of patients and were similar in both arms (p = 0.86). However, the mean rectum 2 cc dose was significantly lower in the IC-ISBT arm (p = 0.038). ConclusionsCombined IC-ISBT is a safe and effective approach to treat ICBT unsuitable cases. It integrates the benefits of ICBT to the adaptability of ISBT around various targets and should be practiced whenever feasible to provide superior outcomes in locally advanced cervical cancer.