IntroductionPatients with non-muscle-invasive bladder cancer (NMIBC) have a good survival but are at high risk for tumour recurrence and disease progression. It is important to identify lifestyle habits that may reduce the risk of recurrence and progression and improve health-related quality of life (HRQOL). This paper describes the rationale and design of the UroLife study. The main aim of this study is to evaluate whether lifestyle habits are related to prognosis and HRQOL in patients with NMIBC.Methods and analysisThe UroLife study is a multicentre prospective cohort study among more than 1100 newly diagnosed patients with NMIBC recruited from 22 hospitals in the Netherlands. At 6 weeks and 3, 15 and 51 months after diagnosis, participants fill out a general questionnaire, and questionnaires about their lifestyle habits and HRQOL. At 3, 15 and 51 months after diagnosis, information about fluid intake and micturition is collected with a 4-day diary. At 3 and 15 months after diagnosis, patients donate blood samples for DNA extraction and (dietary) biomarker analysis. Tumour samples are collected from all patients with T1 disease to assess molecular subtypes. Information about disease characteristics and therapy for the primary tumour and subsequent recurrences is collected from the medical records by the Netherlands Cancer Registry. Statistical analyses will be adjusted for age, gender, tumour characteristics and other known confounders.Ethics and disseminationThe study protocol has been approved by the Committee for Human Research region Arnhem-Nijmegen (CMO 2013-494). Patients who agree to participate in the study provide written informed consent. The findings from our study will be disseminated through peer-reviewed scientific journals and presentations at (inter)national scientific meetings. Patients will be informed about the progress and results of this study through biannual newsletters and through the website of the study and of the bladder cancer patient association.

The aim of our study was to investigate adherence to lifestyle recommendations and lifestyle changes after diagnosis in patients with non-muscle invasive bladder cancer (NMIBC). Second, we aimed to identify distinct trajectories of lifestyle change and their correlates. We analysed data of 935 patients with NMIBC from a prospective cohort study at six weeks (evaluating pre-diagnostic lifestyle), three months, and fifteen months after diagnosis. An overall lifestyle score (range 0–7) was calculated based on the 2018 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) recommendations focusing on diet, body mass index, and physical activity. Linear mixed models were used to analyse absolute lifestyle changes over time. Distinct trajectories of change were identified with latent class trajectory models. We found an overall lifestyle score of 3.3 which remained constant over time. The largest lifestyle changes were observed for the consumption of red and processed meat (−96 g/week) and fruit and vegetables (−38 g/day). Two to four trajectory groups were identified for each single lifestyle behaviour. Correlates differed per trajectory group. In conclusion, adherence to the WCRF/AICR recommendations was low. Small to moderate changes in and different trajectories of single lifestyle behaviours were observed. Effective strategies for lifestyle improvement are warranted.