Benefit of Neoadjuvant Cisplatin-based Chemotherapy for Invasive Bladder Cancer Patients Treated with Radiation-based Therapy in a Real-world Setting: An Inverse Probability Treatment Weighted Analysis

In this study, neoadjuvant cisplatin-based chemotherapy was associated with prolonged survival when given before curative radiation-based therapy for patients with muscle-invasive bladder cancer, and should be considered for eligible patients who elect for this bladder-sparing approach. Neoadjuvant chemotherapy (NAC) improves survival for patients with muscle-invasive bladder cancer (MIBC) treated with radical cystectomy. Studies on the potential benefit of NAC before radiation-based therapy (RT) are conflicting. To evaluate the effect of NAC on patients with MIBC treated with curative-intent RT in a real-world setting. The study cohort consisted of 785 patients with MIBC (cT2-4aN0-2M0) who underwent RT at academic centers across Canada. Patients were classified into two treatment groups based on the administration of NAC before RT (NAC vs no NAC). The inverse probability of treatment weighting (IPTW) with absolute standardized differences (ASDs) was used to balance covariates across treatment groups. The impact of NAC on complete response, overall, and cancer-specific survival (CSS) after RT in the weighted cohort was analyzed. After applying the exclusion criteria, 586 patients were included; 102 (17%) received NAC before RT. Patients in the NAC subgroup were younger (mean age 65 vs 77 yr; ASD 1.20); more likely to have Eastern Cooperative Oncology Group performance status 0–1 (87% vs 78%; ASD 0.28), lymphovascular invasion (32% vs 20%; ASD 0.27), higher cT stage (cT3–4 in 29% vs 20%; ASD 0.21), and higher cN stage (cN1–2 in 32% vs 4%; ASD 0.81); and more commonly treated with concurrent chemotherapy (79% vs 67%; ASD 0.28). After IPTW, NAC versus no NAC cohorts were well balanced (ASD