Sociodemographic disparities in incidence rates of advanced and low-risk prostate cancer as a proxy for diagnostic activity.

BACKGROUND

Inequity in prostate cancer detection can be assessed by relating the diagnostic intensity to the incidence rate of advanced disease in different population groups, according to factors such as socioeconomic status or ethnicity.

METHODS

We used nationwide Swedish register data from Prostate Cancer data Base Sweden 5.0 and Statistics Sweden, which enabled us to estimate incidence rates of low-risk prostate cancer (a proxy for diagnostic activity) and advanced disease (locally advanced and/or metastatic) across population groups according to household income, country of birth, and neighborhood-level characteristics.

RESULTS

We found a gradient in the age-standardized incidence of low-risk prostate cancer across income groups, from 60 per 100,000/year in men with high to 34 per 100,000/year in men with low household income: adjusted incidence rate ratio (IRR) 0.65 (95% confidence interval [CI] 0.59-0.71). The gradient in the incidence of advanced disease had the opposite direction, from 44 to 60 per 100,000/year, IRR 1.43 (95% CI 1.31-1.56). Immigrants from a non-Nordic country (nearly 40% from Asia) had lower incidence rates of both low-risk (IRR 0.47, 95% CI 0.42-0.53) and advanced disease (IRR 0.65, 95% CI 0.58-0.73) than men born in a Nordic country. Neighborhood-level analysis considering economic standard, share of immigrants, and degree of urbanization did not clearly differentiate the incidence of advanced disease.

INTERPRETATION

Our results suggest that measures to facilitate early detection of prostate cancer should be targeted to men with a low income. A low diagnostic activity for prostate cancer among immigrants from countries with low background risk may not imply unjustified social disparity.