This study analyzed a cohort of 27 patients treated with transvaginal HDR-ISBT between January 2018 and December 2023. The cohort was divided into two distinct groups based on the implantation method: 16 cases utilized the 3D-PT-assisted approach, and 11 cases were treated using freehand implantation.

The clinical efficacy of the intervention was assessed through several key metrics, including the objective response rate (ORR), local progression-free survival (LPFS), and overall survival (OS). The results demonstrated a robust ORR of 85.2% across the entire cohort, with a complete response (CR) rate reaching 48.1%. Looking at survival data, the 1-year LPFS rate was 46.7%, followed by 35.0% at 3 years, and 26.3% at 5 years.

Dosimetric parameters such as HR-CTV D90 (EQD2) and V100 were analyzed to ensure that the target volume received the prescribed dose while controlling dose distribution. The analysis revealed a critical threshold: an HR-CTV D90 (EQD2) less than 51 Gy was consistently associated with poorer LPFS, underscoring the importance of achieving high dose conformity to the clinical target volume (CTV).

A key focus of the research was comparing the precision of the two implantation methodologies. The 3D-PT group demonstrated superior dosimetric performance compared to the freehand group. Specifically, patients treated with 3D-PT-assisted implantation achieved higher values for both HR-CTV D90 and V100. Furthermore, the deviation between the dose actually delivered and the dose prescribed (HR-CTV D90 EQD2) was found to be more tightly distributed in the 3D-PT group, suggesting enhanced geometric accuracy and dose optimization.

Despite the observed dosimetric advantages of the 3D-PT technique, the study found no statistically significant differences between the 3D-PT and freehand groups regarding the primary clinical outcomes of ORR, LPFS, or OS. However, a notable difference emerged in toxicity profiles.

The study's conclusion was that transvaginal HDR-ISBT appears to be a feasible salvage treatment option for centrally recurrent pelvic gynecologic malignancies after prior radiotherapy.

It is crucial to interpret these results within the context of the study’s limitations. The researchers explicitly noted that the findings should be viewed as hypothesis-generating, primarily due to the small sample size and inherent challenges in fully adjusting for potential confounding variables in this retrospective analysis.

Subject of Research: Efficacy and dosimetric characteristics of 3D-PT-assisted HDR-ISBT in salvage treatment for recurrent pelvic gynecologic cancers.

Article Title: Clinical outcomes and dosimetric characteristics of salvage transvaginal HDR-ISBT for centrally recurrent pelvic gynecologic malignancies after prior radiotherapy: a single-center retrospective study

Article References: Li, M., Li, S., Li, Y., Jiang, W., Deng, X., Sun, H., Lei, R., Wang, J., Qu, A., & Jiang, P. (2026). Clinical outcomes and dosimetric characteristics of salvage transvaginal HDR-ISBT for centrally recurrent pelvic gynecologic malignancies after prior radiotherapy: a single-center retrospective study. BMC Cancer. https://doi.org/10.1186/s12885-026-17079-8

Image Credits: AI Generated

DOI: 10.1186/s12885-026-17079-8

Keywords: Brachytherapy, HDR-ISBT, Gynecologic Malignancy, Salvage Therapy, Dosimetry, 3D-Printing, Clinical, outcomes, dosimetric, characteristics, salvage, transvaginal