Bi-plane trans-rectal ultrasound (BTRUS) guided prostate perineal template based high dose rate interstitial brachytherapy (HDRIBT) for vaginal vault recurrence.

BACKGROUND

There is limited evidence on the optimal management of vaginal vault recurrence (VVR) in patients with gynecological cancers. Real time bi-plane trans-rectal ultrasound (BTRUS) guidance with prostate perineal template with grid (PPTG) can ensure optimal placement of brachytherapy (BT) applicators for conformal high dose rate interstitial brachytherapy (HDRIBT) dose delivery.

MATERIALS AND

METHODS

The clinical outcome and HDRIBT dosimetric data of six patients with histologically confirmed recurrent or persistent carcinoma of the endometrium (3) and cervix (3) who underwent definitive PPTG based BTRUS-HDRIBT between 2019 and 2023 were retrospectively analysed. The local control (LC) and progression free survival (PFS) for five out of six patients with VVR were analysed by the Kaplan-Meier method using RStudio ver.2023.12.0+369 software. Dose volume uniformity index (DVUI) and dose volume conformity index (DVCI) were used to assess the HDRIBT plan quality.

RESULTS

The prescribed dose (PD) was 6 to 10 Gy. The two year LC rate and PFS for five patients are 100% [95% confidence interval (CI): 100%, 100%] and 80% (95% CI: 52%, 100%) respectively. Optimal mean DVUI (range 0.74-0.98) and mean DVCI (1.00) was achieved. At median follow up of 19 months, 3 patients are alive and free of disease. Most common toxicity is grade 1 hematuria.

CONCLUSION

PPTG based BTRUS-HDRIBT for VVR allows real time tumor visualization for optimal applicator insertion to deliver highly conformal tumoricidal dose and maximize LC rate. Radiation oncologists dealing with prostate HDRIBT already possess this skill and this "dying art" can be readily transferable to female genital tract tumors.