Trends in the Incidence of Fatal Prostate Cancer in the United States by Race

Abstract

Background

Prostate-specific antigen (PSA) testing has dramatically changed the composition of prostate cancer (PCa), making it difficult to interpret incidence trends. New methods are needed to examine temporal trends in the incidence of clinically significant PCa and whether trends vary by race.

Objective

To conduct an in-depth analysis of incidence trends in clinically significant PCa, defined as cases in which PCa was the underlying cause of death within 10 yr of diagnosis.

Design, setting, and participants

We extracted incident PCa cases during the period 1975–2002 and associated causes of death and survival through 2012 from nine cancer registries in the population-based Surveillance Epidemiology and End Results program database.

Outcome measurements and statistical analysis

We applied joinpoint regression analysis to identify when significant changes in trends occurred and age–period–cohort models to examine longitudinal and cross-sectional trends in the incidence of fatal PCa.

Results and limitations

Among 51 680 fatal PCa cases, incidence increased 1% per year prior to 1992, declined 15% per year from 1992 to 1995, and further declined by 5% per year through 2002. Age-specific incidence rates of fatal disease decreased >2% per year among men aged ≥60 yr, yet rates remained relatively stable among men aged ≤55 yr. Fatal disease rates were >2-fold higher in black men compared with white men, a racial disparity that increased to 4.2-fold among younger men.

Conclusions

The incidence of fatal PCa substantially declined after widespread PSA screening and treatment advances. Nevertheless, rates of fatal disease among younger men have remained relatively stable, suggesting the need for additional attention to early onset PCa, especially among black men. The persistent black-to-white racial disparity observed in fatal PCa underscores the need for greater understanding of the causes of this difference so that strategies can be implemented to eliminate racial disparities.

Patient summary

We assessed how the incidence of ultimately fatal prostate cancer (PCa) changed over time. We found that the incidence of fatal PCa declined by >50% since the introduction of prostate-specific antigen testing and advances in treatment options; however, incidence rates among younger men remained relatively stable, and younger black men exhibited a 4.2-fold higher risk for fatal disease compared with white men.

Introduction

Prostate cancer (PCa) is the most frequently diagnosed cancer among men in the United States, with 180 890 new cases estimated for 2016 [1]. Despite notable improvements in PCa mortality rates in the United States over the past few decades [2], it is estimated that 26 120 men (8% of male cancer deaths) will die from this disease in 2016 [1]. Racial disparities in PCa are higher than for any other malignancy, with black men exhibiting a 2.5-fold greater risk of death from PCa compared with white men [1], [3].

There has been a substantial increase in PCa incidence rates in the United States over the past few decades largely due to the increased detection of asymptomatic disease, first through transurethral prostatectomy (TURP) for benign prostatic hyperplasia [4], followed by widespread prostate-specific antigen (PSA) testing beginning in 1986 [5], [6]. The subsequent decrease in PCa incidence rates, attributed to depletion of the latent PCa reservoir in the population, rendered the now-familiar “spike” in overall PCa incidence rates [6].

Accurate interpretation of clinically significant PCa incidence trends has been difficult because of the high prevalence of indolent disease and changes in screening practices. A majority of studies examining PCa trends have focused on the date of death (mortality rate) as opposed to the date of diagnosis [7], [8], which is a more applicable time metric for assessing disease trends during a period of clinical change. In addition, no study in the past decade examined trends using age–period–cohort analysis [9], likely because of unstable parameters resulting from the PCa incidence rate spike.

To overcome these problems and to provide an in-depth analysis of clinically significant PCa incidence trends and racial disparities, we assessed trends in the incidence of fatal PCa, defined as death from this disease within 10 yr of diagnosis [10].