The following is a summary of “Bladder only versus bladder plus pelvic lymph node chemoradiation for muscle-invasive bladder cancer,” published in the July 2023 issue of the Urologic Oncology by Patel et al.

Chemoradiation therapy (CRT) that spares the bladder is the definitive first-line treatment for muscle-invasive bladder cancer. Uncertainty surrounds the optimal radiotherapy target volume, either bladder-only (BO) or bladder plus pelvic lymph nodes (BPN). From 2004 to 2016, researchers identified 2,104 patients in the National Cancer Database with cT2-4N0M0 bladder urothelial cell carcinoma treated with CRT after maximal transurethral resection. The exposure of interest was the treatment volume of BO versus BPN. The primary outcome was overall survival (OS), compared between groups using Kaplan-Meier and Cox proportional hazards with multiple variables. 

An interaction term between clinical T stage (T2 vs. T3–4) and radiation modality (three-dimensional conformal radiotherapy vs. intensity-modulated radiotherapy or proton therapy) was evaluated using sensitivity analysis. The Cochran-Armitage test was used to compare the annual usage of BO and BPN from 2004 to 2016. About 578 patients were administered BO, and 1,526 patients were administered BPN CRT. From 2004 to 2016, there was a significant increase in BPN usage (66.9% to 76.8%, P<  0.0001). 

With a median follow-up of 6.2 years, there was no difference in survival between groups: 5-year OS 27.4% (95% CI 23.4%–31.4%) in the BO group versus 31.9% (95% CI 29.3%–34.6%) in the BPN group, and 13.1% (95% CI 9.7%–17.1%) in the BO group versus 13.2% (95% CI 10.7%–16.0%) in the BPN group, respectively (log-rank P = 0.10. On multivariable analysis, there was no association between BPN and OS (adjusted HR 0.90, 95% confidence interval [CI] 0.81–1.02, P = 0.09). Based on a sensitivity analysis, they found no distinction between the T stage and radiation modality. Radiation of pelvic lymph nodes has increased in the United States, but it may not affect the long-term survival of patients with node-negative muscle-invasive bladder cancer (MIBC). In prospective trials, such as SWOG/NRG 1806, examining the optimization of radiation treatment volumes for CRT of MIBC will be essential.

Source: sciencedirect.com/science/article/abs/pii/S107814392200494X