Racial differences in PSA screening interval and stage at diagnosis.

Objectives: This study examined PSA screening interval of black and white men aged 65 or older and its association with prostate cancer stage at diagnosis.

Methods: SEER-Medicare data were examined for 18,067 black and white men diagnosed with prostate cancer between 1994 and 2002. Logistic regression was used to assess the association between race, PSA screening interval, and stage at diagnosis. Analysis also controlled for age, marital status, comorbidity, diagnosis year, geographic region, income, and receipt of surgery.

Results: Compared to whites, blacks diagnosed with prostate cancer were more likely to have had a longer PSA screening interval prior to diagnosis, including a greater likelihood of no pre-diagnosis use of PSA screening. Controlling for PSA screening interval was associated with a reduction in blacks' relative odds of being diagnosed with advanced (stage III or IV) prostate cancer, to a point that the stage at diagnosis was not statistically different from that of whites (OR=1.12, 95% CI=0.98-1.29). Longer intra-PSA intervals were systematically associated with greater odds of diagnosis with advanced disease.

Conclusions: More frequent or systematic PSA screening may be a pathway to reducing racial differences in prostate cancer stage at diagnosis, and, by extension, mortality.