Abstract
PURPOSE: Carcinoma in situ (CIS) is a flat, high-grade, and aggressive form of urothelial carcinoma with a high risk of progression to muscle-invasive disease and metastasis. This study aimed to investigate differences in clinical outcomes and survival among patients with primary, secondary, and concomitant CIS of the bladder. METHODS: A total of 209 patients diagnosed with CIS between 2010 and 2022 in our department with a minimum follow-up of 12 months were retrospectively analyzed. Patients with muscle-invasive cancer at diagnosis, those with recurrence within one month after diagnosis, and those with primary malignant melanoma were excluded. The recurrence, progression, and cancer-specific mortality rates of patients receiving Bacillus Calmette-Guérin therapy for CIS were analyzed. RESULTS: A total of 96 patients with primary (n = 18), secondary (n = 29), and concomitant CIS (n = 49) were included in the analysis. The median follow-up was 52.2 months. Patients with secondary CIS had a significantly higher recurrence rate than those with concomitant CIS (58.6% vs. 32.7%, p = 0.016). However, no significant difference in progression rates was observed among the three groups. Furthermore, no significant association was observed between CIS subtypes and recurrence-free survival (RFS) (HR = 1.45, 95% CI 0.96-2.46, p = 0.16) or progression-free survival (PFS) (HR = 2.20, 95% CI 0.99-4.87, p = 0.054). CONCLUSION: Secondary CIS had a significantly higher recurrence rate than concomitant CIS. However, no statistically significant association was observed between CIS subtypes and RFS or PFS.