An Up-to-date Assessment of US Prostate Cancer Incidence Rates by Stage and Race: A Novel Approach Combining Multiple Imputation with Age and Delay Adjustment.

BACKGROUND: In the USA, it is unknown whether metastatic prostate cancer incidence has continued to increase and whether racial differences have persisted. OBJECTIVE: Combining multiple imputation with age and delay adjustment, we provide an up-to-date, comprehensive assessment of US prostate cancer incidence trends by stage and race. DESIGN, SETTING, AND PARTICIPANTS: From Surveillance Epidemiology and End Results (SEER)-18, 774 240 prostate cancer cases were diagnosed during 2004-2017. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Multiple imputation assigned prostate cancer stage to the 4.7% of cases with missing stage, which varied by year and race-ethnicity. SEER delay factors adjusted case counts to anticipated future data corrections. Twenty datasets were imputed, and Rubin's rules were used for summary estimation. Overall and stage-specific rates were estimated and stratified by race and age group. Joinpoint software identified significant temporal changes and estimated annual percentage changes. We compared these estimates without multiple imputation and delay adjustment. RESULTS AND LIMITATIONS: Metastatic prostate cancer incidence increased during 2011-2017, with an annual percentage change of 5.5. This was followed by increases in localized and regional disease since 2014. Non-Hispanic black men continued to have the highest incidence, especially for metastatic disease. The increasing rate of metastatic prostate cancer in non-Hispanic white men aged 50-74 yr accelerated recently, and the incidence was 56% higher in 2017 than in 2004. Rates without multiple imputation and delay adjustment were quantitatively and qualitatively different. This observational study is unable to assign causes to observed changes in prostate cancer incidence. CONCLUSIONS: Multiple imputation and delay adjustment are essential for portraying accurately stage- and race-specific prostate cancer incidence as clinical practice evolves. PATIENT SUMMARY: In the USA, diagnosis of prostate cancer that has spread to distant sites (metastatic disease) continues to increase. Black men continue to have higher risks of being diagnosed with metastatic prostate cancer than other race-ethnicities.