Patterns of neoadjuvant chemotherapy (NAC) use in stage II-III bladder cancer: A California Cancer Registry (CCR) analysis.

647 Background: NAC followed by radical cystectomy (RC) improves survival compared to RC alone in patients with muscle invasive bladder cancer (MIBC), yet real-world uptake has lagged. Adjuvant chemotherapy (AC) for those not receiving NAC has been employed though survival benefit has not been established. With evolving perioperative regimens involving immunotherapy changing the treatment landscape, understanding patterns of treatment over time is important. Methods: We evaluated patients with Stage II-III bladder cancer aged > 20, diagnosed from 2004-2022 in the CCR, who underwent RC to assess receipt of both systemic and surgical treatment. Descriptive statistics summarized characteristics of the study population by receipt of NAC + RC, RC + AC, or RC alone among patients. Multivariable logistic regression models identified factors associated with receipt of NAC + RC vs those receiving either RC + AC or RC alone. Results: Among 6749 eligible patients, 2724 (40.4%) received NAC + RC, 438 (6.5%) received RC + AC, and 3587 (53.1%) underwent RC alone. Receipt of NAC was significantly associated with more recent diagnosis (2014-2022 vs 2004-2013): odds ratio [OR] 7.50, 95% CI 6.6.3-8.48), higher neighborhood socioeconomic status (SES) (OR 1.33, 95% CI 1.14-1.56, highest vs lowest tertile), male sex (OR 1.17, 95% CI 1.02-1.34) and care at an NCI-designated Cancer Center (OR 1.40, 95% CI 1.25-1.57). Significantly lower odds of NAC use were observed for those aged > 80 (vs age 20-49; OR 0.31, 95% CI 0.22-0.43), with a Charlson comorbidity score > 1 (vs 0, OR: 0.65, 95% CI 0.57-0.75), and Hispanic individuals (vs non-Hispanic White; OR 0.82, 95% CI 0.69-0.99). Conclusions: NAC use has increased over time, but utilization is lower among older individuals, women, those living in lower SES neighborhoods, Hispanic individuals and those with more comorbidities. These results can help to shape future intervention and optimize treatment utilization as perioperative approaches with broader eligibility criteria emerge.