Neoadjuvant versus adjuvant chemotherapy in muscle-invasive bladder cancer: The RealBLADDER study—Results on behalf of the GOIRC.

e16503 Background: In regard to resectable muscle-invasive bladder cancer (MIBC) patients, treatment with radical cystectomy (RC) and perioperative platinum-based chemotherapy (CT) (neoadjuvant or adjuvant) represents the standard of care. Perioperative treatment can improve overall survival (OS), and the most robust evidence are in favor of neoadjuvant CT. RealBLADDER is an observational study aiming to describe the use and the impact on survival of perioperative CT for patients with MIBC in an Italian real-world setting. Methods: RealBLADDER is a multicentric, observational, retrospective and prospective study, which enrolled patients with MIBC treated with perioperative CT from June 2018 up to June 2023. The primary endpoint was the rate of pathological complete response (pCR)(<pT1), defined as the absence of residual tumor cells in bladder and nodes at the pathological examination after neoadjuvant CT. Secondary endpoints were disease-free survival (DFS), OS and surgical outcomes (morbidity and mortality rates). DFS and OS by setting of chemotherapy were determined. Results: 172 eligible patients were identified. One hundred and thirty-six patients (79.1%) received neoadjuvant and 36 (20.9%) received adjuvant CT. The rate of pCR was 43.3%. The rate of surgical morbidity and mortality were 20.9% and 0%, respectively. Compared to adjuvant chemotherapy, 12-months DFS was improved in patients treated with neoadjuvant CT (p=0.042). Notably, patients treated with neoadjuvant CT had 12-months OS longer in than those treated with adjuvant CT (p=0.043). Conclusions: This real-world analysis of Italian patients with MIBC confirmed that neoadjuvant chemotherapy is associated with a high rate of pCR and low rate of surgical morbidity and mortality supporting the use of neoadjuvant CT in MIBC prior to RC.