Evaluation of dose–Volume-based image-guided high-dose-rate brachytherapy in carcinoma uterine cervix: A prospective study

Abstract

Background: In recent few decades, the evolution in imaging technology, especially computed tomography (CT) and magnetic resonance imaging, results in widespread availability and its use in high-dose-rate (HDR) intracavitary brachytherapy (ICBT) applications. Aim: The present study was aimed to analyze the cumulative dose–volume histogram of the tumor and organs at risk (OARs) in three-dimensional (3D) CT image-based brachytherapy planning and clinical outcomes of the treated patients. Materials and Methods: This prospective observational study included 40 patients with carcinoma cervix. After external beam radiotherapy (EBRT), a dose of 6 Gy per fraction of HDR ICBT in four fractions with a total dose to point “A” approximately 80–85 Gy was given. For planning, the tumor volumes (high-risk clinical target volume [HR-CTV]) and volume of OARs (bladder, rectum, and sigmoid colon) were contoured on each CT slice. The dose–volume parameters, i.e., minimum dose received to 90% and 100% by HR-CTV volume (D90 and D100) for target and the maximum dose received by minimum volume of 2CC (D2CC) for OARs, were calculated and assessed for clinical response in patients. Results: The mean D2CC dose was 18.24 ± 0.93 Gy, 16.44 ± 1.11 Gy, and 16.37 ± 0.67 Gy for bladder, rectum, and sigmoid colon, respectively. The combined (EBRT and HDR ICBT) mean equieffective dose in 2 Gy per fraction (EQD2) dose for bladder was 76.71 ± 2.05 Gy, for rectum was 72.82 ± 2.58 Gy, and for sigmoid colon was 72.71 ± 1.41 Gy, and its comparison with baseline values showing P < 0.01 for bladder, rectum, and sigmoid colon was considered statistically significant. The mean EQD2 dose of HR-CTV D90 was 151 ± 27.3 Gy. Patients who had received HR-CTV D90 of >90 Gy compared with <90 Gy had exceptionally better local control and complete response. Conclusion: The present study suggested that CT is a favorable modality for treatment planning in cervical cancer with limited resources setup in terms of improved tumor coverage, lesser toxicity, confirmation of applicator placement, and accounting dose to OARs.