ESTRO 2024 - Abstract Book

S2330

Clinical - Urology

ESTRO 2024

Median follow up from completion of RT was 18.5 months (range, 0.8-75 months). Median OS was 25.1 months (95% CI 13.8-74.6 months). Estimated 1-year OS was 73%, and 2-year OS was 61%. Estimated 1-year PFS was 52%. 17% developed local bladder failure as a component of progression. All local bladder failure events occurred within the first 12 months following RT. 1 patient underwent salvage cystectomy for muscle invasive recurrence and 1 patient underwent TURBT and intravesical gemcitabine for T1 recurrence. 23% of patients developed lymph node or distant metastases. At last follow up, 33% were alive and disease free. Among those who are disease free, 4 patients had T3 and 4 patients had T4 disease and 2 were node positive. On univariate analysis, variant histology (p=0.006) and hydronephrosis (p=0.017) were predictive of worse OS. On multivariate analysis, both variant histology (p=0.007) and hydronephrosis (p=0.02) remained significant. Estimated 1 year OS with pure urothelial histology was 83% whereas variant histology was 58% (p=0.001, log rank). Acute grade 3 GU and GI toxicities occur in 10% and 0% respectively with hospitalization for complicated UTI comprising the majority of grade 3 events. Late grade 3+ GU and GI toxicity occurred in 7% and 5%, respectively, including a grade 4 GI event with colovesical fistula requiring colostomy from a tumor that was invading the sigmoid prior to RT.

Conclusion:

In this unselected cohort with LA-MIBC treated with RT, both local and distant failures remain relevant with a favorable toxicity profile. Further investigation is warranted to identify novel radiosensitizers to improve local control and useful biomarkers to select those who benefit from systemic therapy intensification.

Keywords: Bladder cancer, Locally advanced, Radiotherapy