Fast and accurate recurrent event analysis for genome-wide association studies.

Many diseases recur after recovery, for example, recurrences in cancer and infections. However, research is often focused on analysing only time-to-first recurrence, thereby ignoring any subsequent recurrences that may occur after the first. Statistical models for the analysis of recurrent events are available, of which the extended Cox proportional hazards frailty model is the current state-of-the-art. However, this model is too statistically complex for computationally efficient application in high-dimensional data sets, including genome-wide association studies (GWAS). Here, we develop an application for fast and accurate recurrent event analysis in GWAS, called SPARE (SaddlePoint Approximation for Recurrent Event analysis). In SPARE, every DNA variant is tested for association with recurrence risk using a modified score statistic. A saddlepoint approximation is implemented to achieve statistical accuracy. SPARE controls the Type I error, and its statistical power is similar to existing recurrent event models, yet SPARE is significantly faster. An application of SPARE in a recurrent event GWAS on bladder cancer for 6.2 million DNA variants in 1,443 individuals required less than 15 min, whereas existing recurrent event methods would require several weeks.

Adherence to lifestyle recommendations after non-muscle invasive bladder cancer diagnosis and risk of recurrence.

BACKGROUND: Patients with non-muscle invasive bladder cancer (NMIBC) are at a high risk of tumor recurrence. It has not been previously investigated if adherence to cancer prevention recommendations lowers the risk of recurrence. OBJECTIVES: We examined whether the standardized lifestyle score measuring adherence to the 2018 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) cancer prevention recommendations was associated with the risk of recurrence and progression among patients with NMIBC. METHODS: The study population included patients diagnosed with primary NMIBC between 2014 and 2017 from the prospective cohort UroLife. Lifestyle was assessed at baseline (n = 979; reflecting the prediagnosis period) and 3-mo postdiagnosis (n = 885). The standardized 2018 WCRF/AICR score was constructed based on recommendations for body weight, physical activity, diet, and alcohol intake. We computed multivariable-adjusted HRs and 95% CIs using Cox proportional hazard regression models. RESULTS: During a median follow-up time of 3.7 y, 320 patients developed ≥1 recurrence(s) and 49 experienced progression. Patients in the highest compared with the lowest tertile of postdiagnosis WCRF/AICR scores had a lower risk of first bladder cancer recurrence (HR: 0.74; 95% CI: 0.56, 0.98). No associations were observed for multiple recurrences (HR: 0.90; 95% CI: 0.70, 1.15) or for the baseline score with either first (HR: 1.07; 95% CI: 0.82, 1.40) or multiple recurrences (HR: 1.04; 95% CI: 0.82, 1.31). Improving lifestyle after diagnosis (per 1-point increase) was not significantly associated with the risk of first or multiple recurrence(s) (HR: 0.87; 95% CI: 0.74, 1.02; HR: 0.93; 95% CI: 0.80, 1.08, respectively). No associations were observed for bladder cancer progression, but the power was limited. CONCLUSIONS: Better adherence to the WCRF/AICR cancer prevention recommendations 3 mo after NMIBC diagnosis, but not before diagnosis, is associated with a decreased risk of first bladder cancer recurrence. More studies evaluating postdiagnosis lifestyles are needed to provide solid support for lifestyle recommendations for cancer survivors.