Death rates from prostate cancer have declined at a steady rate since 1992. Cancers of the prostate, lung and bronchus, and colorectum account for about 50% of all newly diagnosed cancers in men. Prostate cancer alone constitutes 28% cases in men. Screening for prostate cancer varies by state and indicates differences in the use of screening for prostate cancer as well as variations between locales. Out all cases of prostate cancer, African American men have an incidence of 62%. African American men are less likely to receive standard therapy for prostate cancer. This discrepancy may indicate that if they were to receive higher quality cancer treatment their survival rates would be similar to whites. Prostate cancer is also extremely heterogeneous: many, perhaps most, prostate cancers are indolent and would never progress to a clinically meaningful stage if left undiagnosed and untreated during a man's lifetime. On the other hand, a subset are potentially lethal, and screening can identify some of these within a window of opportunity for cure. Thus, the concept of PSA screening is advocated by some as a means of detecting "high-risk", potentially lethal prostate cancer, with the understanding that lower-risk disease, if discovered, often does not need treatment and may be amenable to active surveillance. Screening for prostate cancer is controversial because of cost and uncertain long-term benefits to patients. Horan echos that sentiment in his book. Private medical institutes, such as the Mayo Clinic, likewise acknowledge that "organizations vary in their recommendations about who should – and who shouldn't – get a PSA screening test. They conclude: "Ultimately, whether you should have a PSA test is something you'll have to decide after discussing it with your doctor, considering your risk factors and weighing your personal preferences." A study in Europe resulted in only a small decline in death rates and concluded that 48 men would need to be treated to save one life. But of the 47 men who were treated, most would be unable to ever again function sexually and would require more frequent trips to the bathroom. Aggressive marketing of screening tests by drug companies has also generated controversy as has the advocacy of testing by the American Urological Association. One commentator has observed: “[I]t is prudent only to use a single PSA determination as a baseline, with biopsy and cancer treatment reserved for those with significant PSA changes over time, or for those with clinical manifestations mandating immediate therapy... absolute levels of PSA are rarely meaningful; it is the relative change in PSA levels over time that provides insight, but not definitive proof of a cancerous condition necessitating therapy.“