Evaluation of dose distribution to the tumor and organs at risk for cervical cancer patients treated using HDR-ICBT without central tandem applicator: A single center based experience.

Background and purpose: Cervical cancer is the most prevalent type of cancer among women in numerous low and middle-income countries. Tandem-based applicator is a widely used technique in High Dose Rate Intercavitary Brachytherapy (HDR-ICBT) for treating cervical cancer. For cases where central tandem insertion is not feasible due to patient-specific conditions, a ring-only applicator is used as an alternative. This paper presents an assessment of the impacts of dose distribution on cervical cancer treatment using HDR-ICBT without a central tandem applicator.

Materials and method: Total 30 patients with cervical cancer (stage IB to IVA) who received brachytherapy with a ring applicator alone were singled out and used in the study. Orthogonal radiographs were used during dose treatment planning.

Results: Results indicate that the dose normalized to the Equivalent dose in 2 Gy fractions (EQD2) at Manchester Dosimetry System (MDS) point A was 60.60 ± 1.08 Gy, which is significantly below the recommended curative dose of 80 Gy. This suggests that relying solely on a ring applicator may not provide enough radiation doses to the tumor. The results also show that the International Commission on Radiation Units (ICRU) dose point underestimated the radiation doses to the bladder and rectum, with the ratios of maximum dose (D_Max) to D_ICRU for both organs being 1.15.

Conclusion: The study underscores the importance of not exclusively depending on a ring applicator alone in HDR-ICBT treatment for cervical cancer, as it may lead to suboptimal tumor doses. The ICRU point's results show an underestimation of the rectum and bladder dose during HDR-ICBT.