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

Abstract

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.