ESTRO 2025 - Abstract Book

S217

Brachytherapy - Gynaecology

ESTRO 2025

Results: Forty-four treatment fractions for 11 patients were included, of which 28 treatments were IC (20 ring-based and 8 ovoid-based implants) and 16 were IC-IS (ring-tandem with needles). The median GTV-T res was 4 cm 3 (range 1.4-15.3 cm 3 ), with 24 implants in 6 patients with GTV-T res ≤5 cm 3 , and 20 implants in 5 patients with GTV-Tres >5 cm 3 . The median CTV-T HR was 28 cm 3 (15-66 cm 3 ). For patients with GTV-T res ≤5 cm 3 , all patients achieved CTV-T HR D98% constraint of ≥73Gy 10 , GTV-Tres D98% ≥85Gy 10 , CTV-T HR D90% ≥80Gy 10 and CTV-T IR D98% ≥55Gy 10 regardless of the choice of applicator. For patients with GTV-T res >5 cm 3 , all patients achieved CTV-T HR D98% constraint of ≥78Gy 10 , CTV-T HR D90% ≥85Gy 10 and CTV-T IR D98% ≥57Gy 10 , while 1 patient did not achieve GTV-T res D98% of ≥90Gy 10 . The median bladder, rectum, sigmoid and bowel D 2cm3 was 79.3 Gy 3 (IQR 68.9 – 82.2Gy 3 ), 58 Gy 3 (IQR 51.9 – 67.8Gy 3 ), 62.3Gy 3 (IQR 57.6 – 69.4Gy 3 ) and 61.3Gy 3 (IQR 56 - 65Gy 3 ) respectively. The soft dose constraints for OARs were achieved in up to 73% patients (Table 1 and 2).