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: 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, 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 2009 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 observed in 2011: “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.“ history global comparisons of prostate cancer screening screening of psa began in the 1990s. in the european randomized study of screening for prostate cancer (erspc) initiated in the early 1990s, the researchers concluded that psa-based screening did reduce the rate of death from prostate cancer but created a high risk of overdiagnosis, i.e., 1410 men would need to be screened and 48 additional cases of prostate cancer would need to be treated to prevent just one death from prostate cancer within 9 years. a study published in the european journal of cancer (october 2009) documented that prostate cancer screening reduced prostate cancer mortality by 37 percent. by utilizing a control group of men from northern ireland, where psa screening is infrequent, the research showed this substantial reduction in prostate cancer deaths when compared to men who were psa tested as part of the erspc study. a study published in the new england journal of medicine in 2009 found that over a 7 to 10-year period, "screening did not reduce the death rate in men 55 and over." former screening proponents, including some from stanford university, have come out against routine testing. in february 2010, the american cancer society urged "more caution in using the test." and the american college of preventive medicine concluded that "there was insufficient evidence to recommend routine screening." a further study, the nhs comparison arm for protect (cap), as part of the prostate testing for cancer and treatment (protect) study, randomized gp practices with 460,000 men aged 50–69 at centers in 9 cities in britain from 2001–2005 to usual care or prostate cancer screening with psa (biopsy if psa ≥ 3). the "comparison arm" has yet to report as of early 2018.