Long-term oncological outcomes of bladder cancer: a population-based study with a 25-year follow-up.

OBJECTIVE To describe the oncological outcomes for patients with newly diagnosed bladder cancer, as long-term oncological outcomes and natural history of different initial subtypes of diagnoses of bladder cancer are understudied. PATIENTS AND METHODS This was a prospective, multicentre population-based cohort study, where newly diagnosed patients with bladder cancer from 1995 to 1996 in Stockholm County, Sweden were followed. The primary outcome was cancer-specific mortality (CSM), separately analysed for low-grade non-muscle-invasive bladder cancer (NMIBC Low), high-grade non-muscle-invasive bladder cancer (NMIBC High), and muscle-invasive bladder cancer (MIBC). We used cumulative incidence with competing risk to assess survival outcomes. RESULTS In total, 526 patients were included, 396 had NMIBC. Out of 102 patients with T1, 37% died of bladder cancer during the 25-year follow-up. The rate of CSM for NMBIC Low was 3%, NMIBC High 26%, and MIBC 71%, respectively. For the operated patients with MIBC, the 5-year CSM was 39%. Of the 178 patients with NMIBC High, 22% progressed to MIBC, 10% had lymph node progression, and 17% progressed to metastatic disease during the follow-up. The main limitation of the study is that it was established 30 years ago. CONCLUSION In this population-based study, we found that patients with NMIBC High had a persistent risk of CSM up to 25 years from the initial diagnosis, more specifically in patients with T1 tumours. The study demonstrates the importance for optimal treatment for selective high-risk T1 patients with long life expectancy, and high risk of progression.