Image-guided adaptive interventional radiotherapy (modern brachytherapy) boost for vaginal recurrences

Background This study aimed to evaluate clinical outcomes in patients with vaginal recurrences treated with radiotherapy with or without chemotherapy, followed by image-guided interventional radiotherapy (IG-IRT). Methods We retrospectively analyzed patients with vaginal recurrences treated with external beam radiotherapy (EBRT) ± chemotherapy followed by endovaginal high dose rate IG-IRT. The EBRT total dose was 45 Gy. The interventional radiotherapy boost delivered 28 Gy in four high-dose-rate fractions, achieving 85–95 Gy EQD2 (α/β 10) to the high-risk clinical target volume and 60 Gy EQD2 (α/β 10) to the intermediate-risk clinical target volume. The primary endpoint was local control. Secondary endpoints included metastasis-free survival, overall survival, cancer-specific survival, and acute and late toxicities. Results Thirty-two patients (median age, 54 years) were included. Two-year actuarial local control, metastasis-free survival, overall survival, and cancer-specific survival rates were 100%, 77.8%, 93%, and 93%, respectively. At univariate analysis, chemotherapy was significantly associated with a reduced risk of metastasis ( p = 0.0038). Among chemotherapy regimens, cisplatin-based therapy showed the lowest metastatic risk, with metastases occurring in 5% of patients ( p = 0.019). Age > 59 years was significantly associated with increased mortality ( p = 0.026). At multivariate analysis, age was the only independent predictor of mortality ( p < 0.05). Acute grade 2 gastrointestinal and skin toxicity occurred in two patients, while one patient experienced late grade 3 vaginal stenosis. Conclusions Image-guided interventional radiotherapy as a boost following EBRT for vaginal cuff recurrences is an effective and safe treatment option, providing excellent local control with a favourable toxicity profile.