ESTRO 2024 - Abstract Book

S2329

Clinical - Urology

ESTRO 2024

464

Digital Poster

Outcomes After Radiotherapy for Locally Advanced and Node Positive Muscle Invasive Bladder Cancer

Comron Hassanzadeh 1 , Omar Alhalabi 2 , Ashish Kamat 3 , Jianjun Gao 2 , Byron Lee 3 , Chad Tang 1 , Lauren Mayo 1 , Charles Guo 4 , Matthew T Campbell 2 , Amishi Shah 2 , Quynh Nguyen 1 , Shalin Shah 1 , Osama Mohamad 1 , Ryan Park 1 , Deborah Kuban 1 , Sangeeta Goswami 2 , Henry Mok 1 , Steven Frank 1 , Karen Hoffman 1 , Neema Navai 3 , Seungtaek Choi 1 1 MD Anderson Cancer Center, Radiation Oncology, Houston, USA. 2 MD Anderson Cancer Center, Medical Oncology, Houston, USA. 3 MD Anderson Cancer Center, Urology, Houston, USA. 4 MD Anderson Cancer Center, Pathology, Houston, USA

Purpose/Objective:

Trimodality therapy (TMT) for muscle invasive bladder cancer (MIBC) yields similar oncologic outcomes compared to radical cystectomy in appropriately selected patients. However, data regarding CRT is enriched with patients with early stage disease and less advanced cases. Locally advanced MIBC (LA-MIBC) and metastatic bladder cancer are often grouped and treated using a regimen of systemic therapy alone traditionally employed for metastatic disease. We explore out institutional experience with patients with LA-MIBC undergoing radiation therapy (RT).

Material/Methods:

We identified 30 patients with non-metastatic, LA-MIBC were treated from 2012 to 2022 with definitive intent RT at MD Anderson Cancer Center. Overall survival (OS), progression free survival (PFS) and local bladder progression were evaluated using Kaplan Meier analysis was used to estimate time to event outcomes. Univariate and multivariate using Cox proportional hazards regression analysis were

Results:

Patients were identified with T3-4N0 or T2-4N+ MIBC who were not candidates for cystectomy and underwent RT. Most were men (59%) with a median age of 74.5 years (range, 31-92). 40% had urothelial carcinoma with variant histology component, including squamous (37%) and glandular (3%) differentiation. Variant histology were predominantly urothelial however. Table 1 summarizes baseline and treatment characteristics. Most patients (87%) were treated concurrent radiosensitizers: 37% pembrolizumab, 17% gemcitabine, 10% cisplatin, 10% 5-FU, 7% carboplatin, and 7% paclitaxel. 13% patients received RT alone. Neoadjuvant chemotherapy/systemic therapy (NAC) was delivered in 63% of patients with 12 patients (40%) receiving multiple lines of systemic therapy prior to RT with ddMVAC as the most common regimen. VMAT/IMRT technique was utilized in 87% of patients with the remainder receiving 3D conformal RT. Median dose of RT was 60Gy (range, 50-65Gy) in 30 fractions (range, 20-36 fractions). 23% received hypofractionated RT (55Gy in 20 fractions). 57% received nodal RT.