Not all patients pursue prostate biopsy after abnormal prostate specific antigen results

In prostate cancer, digital rectal examination (DRE) and serum prostate specific antigen (PSA) are used to evaluate the risk of prostate cancer. However, in published community-based screening samples, not all patients with abnormal test results pursue biopsy. To test the existence of and quantify diagnostic dropout in clinic-based early detection samples, we conducted a prospective patterns-of-care study designed to identify variables associated with pursuit of diagnostic steps. Of 76 patients with abnormal PSA and/or DRE, only 43 (57%) pursued prostate biopsy. Prostate specific antigen, but not age or chart-based comorbidities, was predictive of further diagnostic and therapeutic steps. Among patients with abnormal test results, age and abnormal PSA and DRE, but not chart-based comorbidities, strongly correlated with physician intention to diagnose prostate cancer. The factors that cause diagnostic dropout are unknown, but based on experience with other cancers, they may relate to psychological variables in tested patients. That pursuit of diagnosis and treatment appears to occur with no association with chart-based comorbidities is worrisome given the power of comorbidities to predict mortality in prostate cancer patients. Finally, from a public health perspective, a reproducible dropout phenomenon implies that the positive predictive value of DRE and PSA testing may be seriously underestimated.