Assess the journey: Characterizing muscle-invasive bladder cancer patients who receive neoadjuvant therapy and do not proceed with cystectomy.

746 Background: The standard treatment of muscle invasive bladder cancer (MIBC) is neoadjuvant chemotherapy (NAC) followed by radical cystectomy (RC), offering a 5-10% survival benefit and reducing recurrence by 35%. However, little is known about the patients who start NAC but do not proceed to RC. In the SWOG-8710 trial, 18% of patients did not undergo surgery after NAC. Platinum-based regimens, while generally well tolerated, sometimes cause severe side effects. With increasing NAC use and evolving treatment options, some patients start NAC without completing definitive treatment. This study aims characterize patients who do not proceed with RC, focusing on their NAC experience and alternative treatments. Methods: A retrospective analysis was performed on MIBC patients recommended for neoadjuvant therapy followed by RC between 2020-2023 by a single provider at Stanford Health Care. Eligible patients had clinically localized bladder cancer (cT2-T4N0) who initiated neoadjuvant therapy and were deemed surgical candidates. Patients who were not platinum-eligible received alternative therapies on clinical trials . Data were collected on patient demographics, comorbidities, functional status, renal and hematologic function, and NAC administration. Patients who underwent cystectomy were excluded. Results: A total of 90 patients with MIBC who had a treatment plan involving neoadjuvant therapy followed by RC between 2020-2023 were identified. 22% (20/90) of these patients did not undergo cystectomy. The median age was 76, 75% male, 75% white. 50% of patients had variant or non-urothelial carcinoma histology. 60% were cT2 at time of initial consult. The majority of patients (80%) received platinum-based NAC, with only 4 receiving alternative therapies. One patient died of a stroke before completing NAC. The reasons for not undergoing RC were declining additional treatment (30%) and inability to tolerate surgery due to toxicity from therapy (30%), followed by patient preference of radiation therapy (20%), and disease progression (10%). Two additional patients were taken to the operating room; however, surgery was aborted due to unresectable disease and anesthetic complications. Among those who did not undergo RC, 42% opted for surveillance, 37% received trimodal therapy (TMT), and 21% received additional immunotherapy. Conclusions: In this study, we were able to gain a better understanding of our patient cohort who started neoadjuvant therapy but did not proceed to cystectomy. Reasons for this decision included toxicity related to neoadjuvant therapy, personal desire to forgo surgery, or prioritization of bladder preservation. These findings highlight the need for future efforts aimed at trying to predict this patient population and further comparative analysis of outcomes between this cohort and those who underwent cystectomy.