IMRT as an Alternative Technique for Intracavitary Brachytherapy in Patients with Carcinoma of the Cervix: A Feasibility Study Using Unified Dosimetric Index.

Objective: Intracavitary brachytherapy (ICBT) plays an important role in the management of carcinoma of the cervix. This study attempts to find the feasibility of intensity-modulated radiation therapy (IMRT) as a boost for patients who are not suitable for ICBT in order to improve their disease-free and overall survival.

Methods: Twenty patients with carcinoma of the cervix were included in this study. Nine fields of IMRT and ICBT plans were generated for PTV. Various dosimetric indices like coverage, conformity, homogeneity, and gradient index were calculated, and the corresponding unified dosimetric index (UDI) values were generated. Plans were classified based on combined UDI, and the UDI values were compared with those of ICBT. In addition, rectum and bladder doses were compared.

Results: All the dosimetric indices were within acceptable limits except for the gradient index. The gradient index of the IMRT and ICBT plans were 8.77 ± 0.26 and 1.33 ± 0.06 respectively (p < 0.0001). The mean of combined UDI with standard deviation was 32.557 ± 8.940 and plan quality was calculated from these values. Rectum and bladder doses for ICBT were lesser than IMRT (p < 0.0001).

Conclusion: ICBT is the gold standard for boost RT in carcinoma of the cervix patients. IMRT boost is feasible for patients who are unsuitable on medical grounds for brachytherapy.