Detection of latent prostate cancer from routine screening: comparison with breast cancer screening

A literature review of cost-effectiveness analyses of prostate-specific antigen test in prostate cancer screening

Prostate cancer is the most common non-skin cancer in American men, and prostate-specific antigen (PSA) testing is its common screening procedure. In May 2012, the US Preventive Services Task Force recommended against PSA-based screening. These recommendations contradict the current recommendations of other organizations such as the American Urological Association. The authors conducted a systematic review of PubMed, EMBASE and Cochrane to examine the published literature reporting the cost-effectiveness of PSA-based screening. The authors found ten studies each for US and non-US jurisdiction population. All reviewed studies concluded PSA-based screening to be cost effective in younger men (≤60 years of age) and at higher PSA levels (≥3 ng/ml). Further cost-effectiveness analyses reflecting latest clinical practice and current perspectives regarding adverse outcomes of potentially unnecessary treatment are required, especially from the US government perspective.

Changing trends of prostate cancer in Asia

Although Asian people have the lowest incidence and mortality rates of prostate cancer in the world, these rates have risen rapidly in the past two decades in most Asian countries. Prostate cancer has become one of the leading male cancers in some Asian countries. In 2000, the age-adjusted incidence was over 10 per 100000 men in Japan, Taiwan, Singapore, Malaysia, the Philippines and Israel. Although some of the increases may result from enhanced detection, much of the increased incidence may be associated with westernization of the lifestyle, with increasing obesity and increased consumption of fat. The differences in incidences between native Americans and Asian immigrants are getting smaller, reflecting a possible improvement of diagnostic efforts and changes of environmental risk factors in Asian immigrants. Nevertheless, the huge variations in incidences among ethnic groups imply that there are important genetic risk factors. The stage distributions of prostate cancer in Asian populations are still unfavorable compared to those of Western developed countries. However, a trend towards diagnosing cancer with more favorable prognosis is seen in most Asian countries. Both genetic and environmental risk factors responsible for elevated risks in Asian people are being identified, which may help to reduce prostate cancer incidence in a chemopreventive setting.

A quantitative analysis of the costs and benefits of prostate cancer screening

The present study attempts to quantitate in an economically and clinically meaningful manner the cost and cost-effectiveness of prostate cancer screening and subsequent treatment, including complications from that treatment. Outcome data from large prostate cancer screening trials using prostate specific antigen (PSA) and digital rectal examination (DRE) and PSA alone were used to construct the screening model. The benefit of screening is expressed in years of life saved by screening, which is calculated by comparing the survival rate of men with prostate cancer to the survival rate of men in the general population. The cost of screening, treatment, and complications were estimated using the Medicare data base and published reports on the cost, morbidity and mortality for radical prostatectomy. The cost per year of life saved by prostate cancer screening with PSA and DRE was $2339-3005 for men aged 50-59, $3905-5070 for men aged 60-69, and $3574-4627 overall for men aged 50-69. The cost per year of life saved by prostate cancer screening with PSA alone for men aged 50-70 was $3822-4956. A sensitivity analysis demonstrates that the cost per year of life saved by prostate cancer screening will not change substantially even if the assumptions in this model have been underestimated or overestimated by 100%. This study quantifies only those parameters which can be reliably compared in concrete terms such as dollars, treatment impact on survival, published complication rates and published treatment costs. Using this type of analysis, prostate cancer screening appears to be a cost-effective intervention. However, the issue of whether prostate cancer screening is cost-effective will be decided definitively only when randomized, controlled trials are available to quantify the costs and benefits of prostate cancer screening.Prostate Cancer and Prostatic Diseases (2001) 4, 138-145.

Similarities of prostate and breast cancer: Evolution, diet, and estrogens

Environment determines the risk of both prostate and breast cancer, and this risk can vary >10-fold. In contrast, no risk exists for human seminal vesicle cancer demonstrating tissue specificity. There is also species specificity, because there is no risk for prostate cancer in any other aging mammal except the dog. A study of evolution indicates that the prostate and breast appeared at the same time 65 million years ago with the development of mammals. All male mammals have a prostate; however, the seminal vesicles are variable and are determined by the diet so that species primarily eating meat do not have seminal vesicles. The exception is the human, who has seminal vesicles and consumes meat, although this is a recent dietary change. Human lineage departed from other higher primates 8 million years ago. The closest existing primate to humans is the bonobo (pigmy chimpanzee), which does not eat meat but exists primarily on a high fruit and fresh vegetable diet. Homo sapiens evolved only about 150,000 years ago, and only in the last 10% of that time (10 to 15 thousand years ago) did humans and dogs dramatically alter their diets. This is the time when humans domesticated the dog, bred animals, grew crops, and cooked, processed, and stored meats and vegetables. All current epidemiologic evidence and suggestions for preventing prostate and breast cancer in humans indicates that we should return to the original diets under which our ancestors evolved. The recent development of the Western-type diet is associated with breast and prostate cancer throughout the world. It is believed that the exposure to and metabolism of estrogens, and the dietary intake of phytoestrogens, combined with fat intake, obesity, and burned food processing may all be related to hormonal carcinogenesis and oxidative DNA damage. An explanatory model is proposed.

Prostate cancer screening and management

Several other newer therapeutic modalities are being investigated to determine their potential role in the treatment of prostate cancer. Cryotherapy, microwave hyperthermia, laser therapy, and high-intensity focused ultrasound have all been introduced in recent years. Each of these techniques is based on a different principle, yet they all attempt to kill prostate cancer cells in a minimally invasive manner. Insufficient follow-up data are available to allow strong recommendations regarding these treatments.

The socioeconomic implications of prostate-specific antigen screening

Widespread PSA screening will increase overall health care costs. This increase will not result from the detection of clinically insignificant prostate cancer, but rather from the stage migration caused by prostate cancer screening. This stage migration will result in a larger percentage of men with prostate cancer undergoing early treatment options, which are more expensive than treatment of late disease. More importantly, early detection of prostate cancer will lead to treatment several years earlier than would have occurred otherwise. Because treatment then will be paid for in current rather than future dollars, the opportunity costs of money will make treatment costs resulting from PSA screening greater than treatment costs resulting from traditional detection. The critical question is what benefits will be obtained by the expenditure of these additional health care dollars. If early treatment of clinically localized cancer has little or no effect on cause-specific survival, the additional health care costs will have been spent only to limit eventual treatment of local symptoms in the screened men. If early treatment of prostate cancer can increase survival, the added expense is more worthwhile. Because there are not adequate data available to address this issue, several approaches have been used to develop models to estimate cost-effectiveness. Decision analysis models have been used to evaluate the effectiveness of prostate cancer screening and treatment and have found little or no benefit. The current review has demonstrated how assumptions used in the models can influence the results. Benoit et al also have constructed a model of the effectiveness and cost-effectiveness of prostate cancer, but in this study only concrete parameters such as cost, published complication rates, and survival data were used. This quantitative analysis demonstrated that prostate cancer screening is an effective and cost-effective health care intervention compared with currently accepted medical interventions. Although men aged 50 to 70 years will potentially benefit the most from PSA screening, this benefit will not be realized until these men are in their seventh and eighth decades of life. Society must decide if the years of life saved in these men warrants the use of its limited health care resources. This decision will be easier when randomized, controlled trials are available to quantify the costs and benefits of PSA screening.