Dosimetric study of volume-based planning in high-dose-rate image-guided adaptive brachytherapy planning for cervical cancer

Background: Cervical cancer is a major global health challenge, particularly in low- and middle-income countries. The standard care for locally advanced cases includes concurrent chemoradiotherapy (CCRT) with brachytherapy. Aims and Objectives: This study aimed to evaluate dosimetric parameters using computed tomography (CT)-based volume planning in high-dose-rate (HDR) image-guided adaptive brachytherapy for cervical cancer and assess correlations with local control. Materials and Methods: This cross-sectional study enrolled 32 patients with locally advanced cervical carcinoma who received CCRT followed by CT-based intracavitary brachytherapy. Applicators were inserted under spinal anesthesia, followed by CT simulation and delineation of the high-risk clinical target volume (HR-CTV), intermediate-risk clinical target volume (IR-CTV), and organs at risk, according to the GEC-ESTRO guidelines. Plans were optimized for target and organ-at-risk constraints, administering a total of 21 Gy in 3 weekly fractions using a cobalt-60 after loading system. Results: Among the 32 patients, most were aged 45–55 years, with FIGO stages IIA to IVA. Squamous cell carcinoma accounted for 93.8% of the cases. Locoregional control was achieved in 81.3%; 18.8% had recurrence. The mean tumor volume was 45.22 cc. The mean HR-CTV dimensions were 4.88 cm (height), 5.40 cm (width), and 3.92 cm (thickness). The HR-CTV D90, D98 65.11 Gy, Bladder D2 cc was 85.41 Gy, rectal D2 cc 72.53 Gy, sigmoid D2 cc were 80.75, 65.11, 85.41, 72.53, and 63.33 Gy, respectively. Recurrence was associated with a larger tumor volume, larger HR-CTV, and reduced HR-CTV D90/D98. Outcomes were significantly related to chemotherapy cycles and FIGO stage. Conclusion: Volume-based HDR brachytherapy planning offers dosimetric benefits, ensuring effective target coverage and sparing organs at risk, supporting its implementation for cervical cancer, especially in resource-limited settings.