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.