Multicenter retrospective study of whole-pelvis radiation versus bladder-only radiation for muscle-invasive bladder cancer

The value of pelvic lymph node irradiation is debated for patients with muscle-invasive bladder cancer (MIBC) undergoing curative-intent radiotherapy. A retrospective study at academic centers in Canada compared whole-pelvis radiation therapy (WP-RT) versus bladder-only radiation therapy (BO-RT) for cT2-4aN0-2M0 MIBC. Patients receiving WP-RT were younger and more likely to have ECOG performance status of 0-1, clinical node-positive disease, and lymphovascular invasion. In addition, WP-RT patients were more commonly treated with neoadjuvant and concurrent chemotherapy. In inverse probability of treatment weighting analysis WP-RT and BO-RT groups were well balanced. WP-RT versus BO-RT was not associated with complete response rates post-RT (OR 1.14; p=0.526) but was associated with better cancer-specific survival (HR 0.66; p=0.016) and overall survival (HR 0.68; p=0.002). The authors conclude that in adjusted analysis, WP-RT was associated with better survival outcomes compared with BO-RT for MIBC. This conclusion should be confirmed in a randomized trial.