Lymphovascular invasion as a prognostic factor in pT2 urothelial carcinoma.

e16582 Background: Although neoadjuvant therapy is the standard of care for muscle-invasive bladder cancer, up to 40% of patients still undergo cystectomy without prior treatment. Adjuvant therapy remains non-standardized, particularly for pT2 patients, and we lack widely accepted criteria for selecting pT2 patients for adjuvant therapy. Lymphovascular invasion (LVI) is a well-established prognostic factor, especially for pT3 or higher tumors. Our study aims to explore LVI as a potential negative prognostic factor in pT2 tumors. Methods: We conducted a retrospective multi-institutional analysis of patients from 2006 to 2023 who underwent upfront radical cystectomy and were staged with pT2N0 urothelial carcinoma. Event-free and overall survival were compared in patients with and without LVI. To evaluate event-free survival and overall survival, we used a time-to-event analysis, adjusting for potential confounders using Cox regression. Results: We present an interim analysis involving 105 patients. The prevalence of LVI positive patients was 21.9% (n=23). The median follow up was 61 months. LVI positivity was associated with shorter event-free survival (41 months vs. not reached, HR: 3.73 CI 95% 1.55-8.9. p=0.004) and overall survival (NR vs. NR, HR 2.39 CI 95% 1.06-5.4 p=0.03). At 5 years, 65% of LVI-positive patients remained free of recurrence and alive, compared to 82.9% and 89% for LVI-negative patients, respectively. Conclusions: LVI is a strong adverse prognostic factor in pT2pN0 urothelial carcinoma treated with upfront cystectomy. Event free survival and overall survival were significantly worse in the LVI positive group. Therefore, this population of patients has a greater need for effective adjuvant therapy. Results. LVI positive (n=23) LVI negative (n=82) Age (mean) 64,5 y 66,6 y Gender Male 23 (100%) 63 (76,8%) Histology Urotelial 17 (73,9%) 65 (79,3%) Mixed variants 6 (26,1%) 17 (20,7%) Lymph nodes resected (mean) 10 10 Relapse 8 (34,8%) 17 (20%) EFS (months) 23,2 63,2 OS (months) 29 70