The role of prostate-specific antigen (PSA) testing patterns in the recent prostate cancer incidence decline in the United States

Overview and countermeasures of cancer burden in China

Cancer is one of the leading causes of human death worldwide. Treatment of cancer exhausts significant medical resources, and the morbidity and mortality caused by cancer is a huge social burden. Cancer has therefore become a serious economic and social problem shared globally. As an increasingly prevalent disease in China, cancer is a huge challenge for the country's healthcare system. Based on recent data published in the Journal of the National Cancer Center on cancer incidence and mortality in China in 2016, we analyzed the current trends in cancer incidence and changes in cancer mortality and survival rate in China. And also, we examined several key risk factors for cancer pathogenesis and discussed potential countermeasures for cancer prevention and treatment in China.

Trends of stratified prostate cancer risk in a single Korean province from 2003 to 2021: A multicenter study conducted using regional training hospital data

PURPOSE

To identify changes in prostate cancer (PCa) risk-stratification during the last two decades in Korea, where the social perception of PCa was limited due to a relatively low incidence but has recently been triggered by the rapidly increasing incidence of benign prostate hyperplasia.

MATERIALS AND METHODS

Retrospective data of patients who had received a diagnosis of PCa in a single Korean province (Daegu-Gyeongsangbuk) at all seven training hospitals in the years 2003, 2007, 2011, 2015, 2019, and 2021 were subjected to analysis. Changes in PCa risk-stratification were investigated with respect to serum prostate-specific antigen (PSA), Gleason score (GS), and clinical stage.

RESULTS

Of the 3,393 study subjects that received a diagnosis of PCa, 64.1% had high-risk disease, 23.0% intermediate, and 12.9% low-risk disease. The proportion diagnosed with high-risk disease was 54.8% in 2003, 30.6% in 2019, but then increased to 35.1% in 2021. The proportion of patients with high PSA (>20 ng/mL) steadily decreased from 59.4% in 2003 to 29.6% in 2021, whereas the proportion with a high GS (>8) increased from 32.8% in 2011 to 34.0% in 2021, and the proportion with advanced stage disease (over cT2c) increased from 26.5% in 2011 to 37.1% in 2021.

CONCLUSIONS

In this retrospective study, conducted in a single Korean province, high-risk PCa accounted for the largest proportion of newly registered Korean PCa patients during the last two decades and increased in the early 2020s. This outcome supports the adoption of nationwide PSA screening, regardless of current Western guidelines.

Should Contemporary Western Guidelines Based on Studies Conducted in the 2000s Be Adopted for the Prostate-Specific Antigen Screening Policy for Asian Men in the 2020s?

Though prostate cancer (PCa) is the second most common cancer world widely, there exist substantial differences exist between Asia and the west. Genetic susceptibility and lifestyle may contribute to disproportionately lower incidences and mortalities of PCa in Asian countries, but the differences in diagnostic practices are also likely to contribute, and a large part of them may be explained by the lesser chance of prostate-specific antigen (PSA) testing. In the US, about half of men aged over 50 years had been exposed to the screening test in the early 2000s. The shifts in the risk stratification from the high-risk dominant disease in the late 1980s to the low-risk dominant disease in the early 2000s led to criticism regarding the unconditional nature of PSA-based screening. Based on the conflicting outcomes from the randomized clinical trials which investigated the benefit of PSA testing, US Preventive Study Task Force recommended ceasing mass screening in 2012. Accordingly, guidelines begin to emphasize shared decision-making on the PSA testing narrowing their scopes to men aged 55 to 69 years since 2013. Though most Asian countries have not begun to recognize PCa as a major agenda item until the 2010s, a clear trend of expanding incidence of it implies that the time to come to reconsider PSA testing as a higher priority in the public health sphere in the 2020s. Concerns regarding over-diagnosis and over-treatment of insignificant diseases are imperative. However, the distinctive epidemiologic characteristics of PCa in Asia areas, such as low exposure to the repetitive PSA testing, the recent increase in its incidence driven by the elderly and super-elderly, and racial differences should be considered when it comes to the establishment of screening policy utilizing PSA test.

Age-period-cohort analysis with a constant-relative-variation constraint for an apportionment of period and cohort slopes

Age-period-cohort analysis of incidence and/or mortality data has received much attention in the literature. To circumvent the non-identifiability problem inherent in the age-period-cohort model, additional constraints are necessary on the parameters estimates. We propose setting the constraint to reflect the different nature of the three temporal variables: age, period, and birth cohort. There are two assumptions in our method. Recognizing age effects to be deterministic (first assumption), we do not explicitly incorporate the age parameters into constraint. For the stochastic period and cohort effects, we set a constant-relative-variation constraint on their trends (second assumption). The constant-relative-variation constraint dictates that between two stochastic effects, one with a larger curvature gets a larger (absolute) slope, and one with zero curvature gets no slope. We conducted Monte-Carlo simulations to examine the statistical properties of the proposed method and analyzed the data of prostate cancer incidence for whites from 1973-2012 to illustrate the methodology. A driver for the period and/or cohort effect may be lacking in some populations. In that case, the CRV method automatically produces an unbiased age effect and no period and/or cohort effect, thereby addressing the situation properly. However, the method proposed in this paper is not a general purpose model and will produce biased results in many other real-life data scenarios. It is only useful in situations when the age effects are deterministic and dominant, and the period and cohort effects are stochastic and minor.

Digital rectal examination and its associated factors in the early detection of prostate cancer: a cross-sectional population-based study

BACKGROUND

Digital rectal examination (DRE) is one of the most common strategies for prostate cancer early detection. However, the use for screening purposes has a controversial benefit and potential harms can occur due to false-positive results, overdiagnosis and overtreatment. The objective of this study is to calculate the prevalence and identify factors associated with the receipt of DRE in Brazilian men.

METHODS

We selected men older than 40 from a nationwide population-based survey (13,625 individuals) excluding those with prostate cancer diagnosis. Information was extracted from the most recent database of the Brazilian National Health Survey (PNS 2013). Statistical analysis was carried out to calculate incidence rate ratios, with 95% confidence intervals and p values, through multivariate analysis with Poisson regression and robust variance.

RESULTS

Men having private health insurance (63.3%; CI = 60.5-66.0) presented higher prevalence of DRE than those in the public health system (41.6%; CI = 39.8-43.4). The results show a positive association between DRE and men having private health insurance, aged 60-69, living with a spouse, never smokers, and living in urban areas. Among public health services users, this positive association was observed among men aged 70-79, living with a spouse, having bad/very bad health self-perception, abstainers, ex-smokers, with undergraduate studies, presenting four or more comorbidities, and residing in urban areas.

CONCLUSIONS

Prostate cancer screening with DRE is quite frequent in Brazil, specially among men with private health plans and better access to health services, healthier lifestyle and at more advanced ages, characteristics which increase the risk of overdiagnosis and overtreatment.

Factors influencing prostate cancer treatment decisions for African American and white men

BACKGROUND

Prostate cancer racial disparities in mortality outcomes are the largest in all of oncology, and less aggressive treatment received by African American (AA) patients versus white patients is likely a contributing factor. However, the reasons underlying the differences in treatment are unclear.

METHODS

This study examined a prospective, population-based cohort of 1170 men with newly diagnosed nonmetastatic prostate cancer enrolled from 2011 to 2013 before treatment throughout North Carolina. By phone survey, each participant was asked to rate the aggressiveness of his cancer, and his response was compared to the actual diagnosis based on a medical record review. Participants were also asked to rate the importance of 10 factors for their treatment decision-making process.

RESULTS

Among AA and white patients with low-risk cancer (according to National Comprehensive Cancer Network guidelines), 78% to 80% perceived their cancers to be "not very aggressive." However, among high-risk patients, 54% of AA patients considered their cancers to be "not very aggressive," whereas 24% of white patients did (P < .001). Although both AA and white patients indicated that a cure was a very important decision-making factor, AAs were significantly more likely to consider cost, treatment time, and recovery time as very important. In a multivariable analysis, perceived cancer aggressiveness and cure as the most important factor were significantly associated with receiving any aggressive treatment and were associated with surgery (vs radiation). After adjustments for these factors and sociodemographic factors, race was not significantly associated with the treatment received.

CONCLUSIONS

Racial differences in perceived cancer aggressiveness and factors important in treatment decision making provide novel insights into reasons for the known racial disparities in prostate cancer as well as potential targets for interventions to reduce these disparities.

Low Free Testosterone and Prostate Cancer Risk: A Collaborative Analysis of 20 Prospective Studies

BACKGROUND

Experimental and clinical evidence implicates testosterone in the aetiology of prostate cancer. Variation across the normal range of circulating free testosterone concentrations may not lead to changes in prostate biology, unless circulating concentrations are low. This may also apply to prostate cancer risk, but this has not been investigated in an epidemiological setting.

OBJECTIVE

To examine whether men with low concentrations of circulating free testosterone have a reduced risk of prostate cancer.

DESIGN, SETTING, AND PARTICIPANTS

Analysis of individual participant data from 20 prospective studies including 6933 prostate cancer cases, diagnosed on average 6.8 yr after blood collection, and 12 088 controls in the Endogenous Hormones, Nutritional Biomarkers and Prostate Cancer Collaborative Group.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Odds ratios (ORs) of incident overall prostate cancer and subtypes by stage and grade, using conditional logistic regression, based on study-specific tenths of calculated free testosterone concentration.

RESULTS AND LIMITATIONS

Men in the lowest tenth of free testosterone concentration had a lower risk of overall prostate cancer (OR=0.77, 95% confidence interval [CI] 0.69-0.86; p<0.001) compared with men with higher concentrations (2nd-10th tenths of the distribution). Heterogeneity was present by tumour grade (phet=0.01), with a lower risk of low-grade disease (OR=0.76, 95% CI 0.67-0.88) and a nonsignificantly higher risk of high-grade disease (OR=1.56, 95% CI 0.95-2.57). There was no evidence of heterogeneity by tumour stage. The observational design is a limitation.

CONCLUSIONS

Men with low circulating free testosterone may have a lower risk of overall prostate cancer; this may be due to a direct biological effect, or detection bias. Further research is needed to explore the apparent differential association by tumour grade.

PATIENT SUMMARY

In this study, we looked at circulating testosterone levels and risk of developing prostate cancer, finding that men with low testosterone had a lower risk of prostate cancer.

Optimal Therapy Scheduling Based on a Pair of Collaterally Sensitive Drugs

Despite major strides in the treatment of cancer, the development of drug resistance remains a major hurdle. One strategy which has been proposed to address this is the sequential application of drug therapies where resistance to one drug induces sensitivity to another drug, a concept called collateral sensitivity. The optimal timing of drug switching in these situations, however, remains unknown. To study this, we developed a dynamical model of sequential therapy on heterogeneous tumors comprised of resistant and sensitive cells. A pair of drugs (DrugA, DrugB) are utilized and are periodically switched during therapy. Assuming resistant cells to one drug are collaterally sensitive to the opposing drug, we classified cancer cells into two groups, [Formula: see text] and [Formula: see text], each of which is a subpopulation of cells resistant to the indicated drug and concurrently sensitive to the other, and we subsequently explored the resulting population dynamics. Specifically, based on a system of ordinary differential equations for [Formula: see text] and [Formula: see text], we determined that the optimal treatment strategy consists of two stages: an initial stage in which a chosen effective drug is utilized until a specific time point, T, and a second stage in which drugs are switched repeatedly, during which each drug is used for a relative duration (i.e., [Formula: see text]-long for DrugA and [Formula: see text]-long for DrugB with [Formula: see text] and [Formula: see text]). We prove that the optimal duration of the initial stage, in which the first drug is administered, T, is shorter than the period in which it remains effective in decreasing the total population, contrary to current clinical intuition. We further analyzed the relationship between population makeup, [Formula: see text], and the effect of each drug. We determine a critical ratio, which we term [Formula: see text], at which the two drugs are equally effective. As the first stage of the optimal strategy is applied, [Formula: see text] changes monotonically to [Formula: see text] and then, during the second stage, remains at [Formula: see text] thereafter. Beyond our analytic results, we explored an individual-based stochastic model and presented the distribution of extinction times for the classes of solutions found. Taken together, our results suggest opportunities to improve therapy scheduling in clinical oncology.

Analysis of PSA Velocity in 1666 Healthy Subjects Undergoing Total PSA Determination at Two Consecutive Screening Rounds

The study purpose was to assess PSA velocity (PSAV) in healthy subjects in order to establish a reliable cutoff for the differential diagnosis of prostate cancer in a screening setting. We studied a series of 1666 healthy men aged 55 to 74 years undergoing two total PSA determinations at a four-year interval within a population-based randomized screening trial at the Centro per lo Studio e la Prevenzione Oncologica of Florence. First and second screening round PSA assays (PSA1 and PSA2) were carried out with the same method and by the same laboratory. PSAV (PSA1–PSA2/year) was determined in non-cancer subjects in the overall series or in specific age and PSA subgroups, and in subjects with cancer detected at the second screening round. Average PSAV in 1648 non-cancer subjects was 0.07 ng/mL/year (range −2.18+5.99, 95% CI 0.05–0.09); at least one third of subjects showed a decrease in PSA (negative PSAV), mostly of limited magnitude and in the low PSA range. Average PSAV in the 18 cancer patients was 1.16 ng/mL/year (range 0.10–5.6, 95% CI 0.56–1.77), which is significantly higher (p<0.01) than in non-cancer subjects. None of the cancer patients showed a PSA decrease over time. Whatever cutoff was taken for PSAV, its power to discriminate cancer was limited: in particular the previously used PSAV cutoff of 0.75 ng/mL/year would have included only 42 of the 1648 non-cancer subjects (specificity 97.5%) but excluded eight of the 18 cancer patients (sensitivity 55.5%). At best, with the adopted screening protocol PSAV (cutoff 0.10 ng/mL/year) could have spared 27.9% of non-cancer subjects with PSA ≥2.5 ng/mL further diagnostic assessment and 22.7% of non-cancer subjects with PSA ≥4 ng/mL random sextant biopsy, while missing no cancers. This study provides a reliable estimate of PSAV based on a large unbiased population sample. PSAV is widely variable over time, particularly at low PSA values. PSAV might be of value as an indicator for diagnostic assessment and random sextant biopsy in a screening setting.

Dielectrophoresis-based microfluidic platforms for cancer diagnostics

The recent advancement of dielectrophoresis (DEP)-enabled microfluidic platforms is opening new opportunities for potential use in cancer disease diagnostics. DEP is advantageous because of its specificity, low cost, small sample volume requirement, and tuneable property for microfluidic platforms. These intrinsic advantages have made it especially suitable for developing microfluidic cancer diagnostic platforms. This review focuses on a comprehensive analysis of the recent developments of DEP enabled microfluidic platforms sorted according to the target cancer cell. Each study is critically analyzed, and the features of each platform, the performance, added functionality for clinical use, and the types of samples, used are discussed. We address the novelty of the techniques, strategies, and design configuration used in improving on existing technologies or previous studies. A summary of comparing the developmental extent of each study is made, and we conclude with a treatment of future trends and a brief summary.

Advocacy, support and survivorship in prostate cancer

Across Australia, prostate cancer support groups (PCSG) have emerged to fill a gap in psychosocial care for men and their families. However, an understanding of the triggers and influencers of the PCSG movement is absent. We interviewed 21 SG leaders (19 PC survivors, two partners), of whom six also attended a focus group, about motivations, experiences, past and future challenges in founding and leading PCSGs. Thematic analysis identified four global themes: illness experience; enacting a supportive response; forming a national collective and challenges. Leaders described men's feelings of isolation and neglect by the health system as the impetus for PCSGs to form and give/receive mutual help. Negotiating health care systems was an early challenge. National affiliation enabled leaders to build a united voice in the health system and establish a group identity and collective voice. Affiliation was supported by a symbiotic relationship with tensions between independence, affiliation and governance. Future challenges were group sustainability and inclusiveness. Study findings describe how a grassroots PCSG movement arose consistent with an embodied health movement perspective. Health care organisations who seek to leverage these community resources need to be cognisant of SG values and purpose if they are to negotiate effective partnerships that maximise mutual benefit.

Prostate-specific antigen testing for prostate cancer: Depleting a limited pool of susceptible individuals?

After the introduction of the prostate specific antigen (PSA) test in the 1980s, a sharp increase in the incidence rate of prostate cancer was seen in the United States. The age-specific incidence patterns exhibited remarkable shifts to younger ages, and declining rates were observed at old ages. Similar trends were seen in Norway. We investigate whether these features could, in combination with PSA testing, be explained by a varying degree of susceptibility to prostate cancer in the populations. We analyzed incidence data from the United States' Surveillance, Epidemiology, and End Results program for 1973-2010, comprising 511,027 prostate cancers in men ≥40 years old, and Norwegian national incidence data for 1953-2011, comprising 113,837 prostate cancers in men ≥50 years old. We developed a frailty model where only a proportion of the population could develop prostate cancer, and where the increased risk of diagnosis due to the massive use of PSA testing was modelled by encompassing this heterogeneity in risk. The frailty model fits the observed data well, and captures the changing age-specific incidence patterns across birth cohorts. The susceptible proportion of men is [Formula: see text] in the United States and [Formula: see text] in Norway. Cumulative incidence rates at old age are unchanged across birth cohort exposed to PSA testing at younger and younger ages. The peaking cohort-specific age-incidence curves of prostate cancer may be explained by the underlying heterogeneity in prostate cancer risk. The introduction of the PSA test has led to a larger number of diagnosed men. However, no more cases are being diagnosed in total in birth cohorts exposed to the PSA era at younger and younger ages, even though they are diagnosed at younger ages. Together with the earlier peak in the age-incidence curves for younger cohorts, and the strong familial association of the cancer, this constitutes convincing evidence that the PSA test has led to a higher proportion, and an earlier timing, of diagnoses in a limited pool of susceptible individuals.

Demographic and Past Screening Behaviors of Men Attending a Free Community Screening Program for Prostate Cancer

This study characterizes demographic and past prostate screening behaviors of men who participated in a free screening for prostate cancer. Demographics, past prostate screening behavior, perceived risk, and cancer worry were assessed in 1,680 men. Mean age was 58.2 years, 56% were White, and 76% had health insurance. Men with insurance were more likely to have had a previous prostate-specific antigen (PSA) test and digital rectal exam (DRE). White men were more likely to have had a previous PSA and DRE and to have discussed PSA testing with a physician than African American men. African American men reported greater perceived risk and more worry than White men. Screening differences between African American and White men were explained by insurance status. These results may help guide the development of and promotion for future screening programs. Future efforts should be directed at increasing awareness about screening procedures for prostate cancer.

Baseline Prostate-Specific Antigen Levels in Midlife Predict Lethal Prostate Cancer

PURPOSE

Prostate-specific antigen (PSA) level in midlife predicted future prostate cancer (PCa) mortality in an unscreened Swedish population. Our purpose was to determine if a baseline PSA level during midlife predicts lethal PCa in a US population with opportunistic screening.

MATERIALS AND METHODS

We conducted a nested case-control study among men age 40 to 59 years who gave blood before random assignment in the Physicians' Health Study, a randomized, placebo-controlled trial of aspirin and β-carotene among 22,071 US male physicians initiated in 1982 and then transitioned into a prospective cohort with 30 years of follow-up. Baseline PSA levels were available for 234 patients with PCa and 711 age-matched controls. Seventy-one participants who developed lethal PCa were rematched to 213 controls. Conditional logistic regression was used to estimate odds ratios and the area under the receiver operating characteristic curve, with 95% CIs, of the association between baseline PSA and risk of lethal PCa.

RESULTS

Median PSA among controls was 0.68, 0.88, and 0.96 ng/mL for men age 40 to 49, 50 to 54, and 55 to 59 years, respectively. Risk of lethal PCa was strongly associated with baseline PSA in midlife: odds ratios (95% CIs) comparing PSA in the > 90th percentile versus less than or equal to median were 8.7 (1.0 to 78.2) at 40 to 49 years, 12.6 (1.4 to 110.4) at 50 to 54 years, and 6.9 (2.5 to 19.1) at 55 to 59 years. A total of 82%, 71%, and 86% of lethal cases occurred in men with PSA above the median at ages 40 to 49, 50 to 54, and 55 to 59 years, respectively.

CONCLUSION

PSA levels in midlife strongly predict future lethal PCa in a US cohort subject to opportunistic screening. Risk-stratified screening on the basis of midlife PSA should be considered in men age 45 to 59 years.

Prostate cancer incidence in 43 populations worldwide: An analysis of time trends overall and by age group

Prostate cancer is a significant public health burden and a major cause of morbidity and mortality among men worldwide. Analyzing geographic patterns and temporal trends may help identify high-risk populations, suggest the degree of PSA testing, and provide clues to etiology. We used incidence data available from the International Agency for Research on Cancer (IARC) and certain cancer registries for 43 populations across five continents during a median period of 24 years. Trends in overall prostate cancer rates showed five distinct patterns ranging from generally monotonic increases to peaking of rates followed by declines, which coincide somewhat with changes in the prevalence of PSA testing. Trends in age-specific rates generally mirrored those in the overall rates, with several notable exceptions. For populations where overall rates increased rapidly and then peaked, exemplified in North America and Oceania, the highest incidence tended to be most pronounced and occurred during earlier calendar years among older men compared with younger ones. For populations with almost continual increases in overall rates, exemplified in Eastern Europe and Asia, peaks were evident among men aged ≥ 75 years in many instances. Rates for ages 45-54 years did not clearly stabilize or decline in the majority of studied populations. Global geographic variation remained substantial for both overall and age-specific incidence rates regardless of levels of PSA testing, with the lowest rates consistently in Asia. Explanations for the persistent geographic differences and the continuing increases of especially early-onset prostate cancer remain unclear.

Meta-Analysis of Long-Chain Omega-3 Polyunsaturated Fatty Acids (LCω-3PUFA) and Prostate Cancer

We conducted a systematic review and meta-analysis to estimate the potential association between LCω-3PUFAs and prostate cancer (PC). A comprehensive literature search was performed through 2013 to identify prospective studies that examined dietary intakes of long-chain omega-3 polyunsaturated fatty acids (LCω-3PUFA) or blood biomarkers of LCω-3PUFA status and risk of PC. Random-effects meta-analyses were conducted to generate summary relative risk estimates (SRREs) for LCω-3PUFAs and total PC, and by stage and grade. Subgroup analyses were also conducted for specific fatty acids and other study characteristics. Twelve self-reported dietary intake and 9 biomarker studies from independent study populations were included in the analysis, with 446,243 and 14,897 total participants, respectively. No association between LCω-3PUFAs and total PC was observed (SRRE = 1.00, 95% CI: 0.93–1.09) for the dietary intake studies (high vs. low LCω-3PUFAs category comparison) or for the biomarker studies (SRRE of 1.07, 95% CI: 0.94–1.20). In general, most summary associations for the dietary intake studies were in the inverse direction, whereas the majority of summary associations for the biomarker studies were in the positive direction, but all were weak in magnitude. The results from this meta-analysis do not support an association between LCω-3PUFAs and PC.

Cancer statistics, 2015

Each year the American Cancer Society estimates the numbers of new cancer cases and deaths that will occur in the United States in the current year and compiles the most recent data on cancer incidence, mortality, and survival. Incidence data were collected by the National Cancer Institute (Surveillance, Epidemiology, and End Results [SEER] Program), the Centers for Disease Control and Prevention (National Program of Cancer Registries), and the North American Association of Central Cancer Registries. Mortality data were collected by the National Center for Health Statistics. A total of 1,658,370 new cancer cases and 589,430 cancer deaths are projected to occur in the United States in 2015. During the most recent 5 years for which there are data (2007-2011), delay-adjusted cancer incidence rates (13 oldest SEER registries) declined by 1.8% per year in men and were stable in women, while cancer death rates nationwide decreased by 1.8% per year in men and by 1.4% per year in women. The overall cancer death rate decreased from 215.1 (per 100,000 population) in 1991 to 168.7 in 2011, a total relative decline of 22%. However, the magnitude of the decline varied by state, and was generally lowest in the South (∼15%) and highest in the Northeast (≥20%). For example, there were declines of 25% to 30% in Maryland, New Jersey, Massachusetts, New York, and Delaware, which collectively averted 29,000 cancer deaths in 2011 as a result of this progress. Further gains can be accelerated by applying existing cancer control knowledge across all segments of the population.

Evaluation of new technologies for cancer control based on population trends in disease incidence and mortality

Cancer interventions often disseminate in the population before evidence of their effectiveness is available. Population disease trends provide a natural experiment for assessing the characteristics of the disease and the potential impact of the intervention. We review models for extracting information from population data for use in economic evaluations of cancer screening interventions. We focus particularly on prostate-specific antigen (PSA) screening for prostate cancer and describe approaches that can be used to project the likely costs and benefits of competing screening policies. Results indicate that the lifetime probability of biopsy-detectable prostate cancer is 33%, the chance of clinical diagnosis without screening is 13%, and the average time from onset to clinical diagnosis is 14 years. Less aggressive screening policies that screen less often and use more conservative criteria (e.g., higher PSA thresholds) for biopsy referral may dramatically reduce PSA screening costs with modest impact on benefit.

The relevance of serum levels of long chain omega-3 polyunsaturated fatty acids and prostate cancer risk: A meta-analysis

OBJECTIVE

Our objective was to systematically analyze the evidence for an association between serum level long chain omega-3 polyunsaturated fatty acid (n-3 PUFA) and prostate cancer risk from human epidemiological studies. STUDY PROCEDURES: We searched biomedical literature databases up to November 2011 and included epidemiological studies with description of long chain n-3 PUFA and incidence of prostate cancer in humans. Critical appraisal was done by two independent reviewers. Data were pooled using the general variance-based method with random-effects model; effect estimates were expressed as risk ratio with 95% confidence interval (CI). Heterogeneity was assessed by Chi(2) and quantified by I(2), publication bias was also determined.

RESULTS

In total, 12 studies were included. Significant negative association was noted between high serum level of n-3 PUFA doc-osapentaenoic acid (DPA) and total prostate cancer risk (RR:0.756; 95% CI 0.599, 0.955; p = 0.019). Likewise, a positive association between high blood level of fish oil contents, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and high-grade prostate tumour incidence (RR:1.381; 95% CI 1.050, 1.817; p = 0.021) was noted; however, this finding was evident only after adjustment was done on interstudy variability through the removal of a lower quality study from the pool.

CONCLUSIONS

High serum levels of long chain n-3 PUFA DPA is associated with reduced total prostate cancer risk. While high blood level of EPA and DHA is possibly associated with increased high-grade prostate tumour risk.

Dielectrophoretic Separation of Prostate Cancer Cells

Separation of cancer cells from other biological materials is significant for circulating tumor cell detection in cancer diagnosis and treatment. However, separation of one type of cancer cell from other types of cancer cells can be difficult, since they share similar morphology and biomarkers. In the present work, we have successfully manipulated and isolated LNCaP prostate cancer cells from HCT116 colorectal cancer cells, by dielectrophoresis (DEP) in a microfluidic platform in a continuous operation. In this cell sorter, the prostate cancer cells were treated as target cells and were deflected to a side channel from a main channel as they experienced a negative DEP force, when an AC electric field at the cross-over frequency of the HCT116 cells was supplied. This motion consequently led to the separation of the prostate cancer cells from the colorectal cancer cells. In this manuscript, we report the flow conditions, DEP spectra of the cancer cells and the isolation of LNCaP cells from HCT116 cells. The separation and enrichment factor have been investigated as well.

Lycopene, Tomato Products, and Prostate Cancer Incidence: A Review and Reassessment in the PSA Screening Era

Lycopene has been proposed to protect against prostate cancer through various properties including decreased lipid oxidation, inhibition of cancer cell proliferation, and most notably potent antioxidant properties. Epidemiologic studies on the association between lycopene and prostate cancer incidence have yielded mixed results. Detection of an association has been complicated by unique epidemiologic considerations including the measurement of lycopene and its major source in the diet, tomato products, and assessment of prostate cancer incidence and progression. Understanding this association has been further challenging in the prostate-specific antigen (PSA) screening era. PSA screening has increased the detection of prostate cancer, including a variety of relatively indolent cancers. This paper examines the lycopene and prostate cancer association in light of epidemiologic methodologic issues with particular emphasis on the effect of PSA screening on this association.

Data and trends in cancer screening in the United States: results from the 2005 National Health Interview Survey

BACKGROUND

This paper examines the prevalence of cancer screening use as reported in 2005 among US adults, focusing on differences among historically underserved subgroups. We also examine trends from 1992 through 2005 to determine whether differences in screening use are increasing, staying the same, or decreasing.

METHODS

Data from the National Health Interview Surveys between 1992 and 2005 were analyzed to describe patterns and trends in cancer screening practices, including Papanicolaou test, mammography, prostate-specific antigen, and colorectal screening. Logistic regression was used to report 2005 data for population subgroups defined by several demographic and socioeconomic characteristics.

RESULTS

Rates of use for cancer tests are rising only for colorectal cancer, due largely to the increase in colorectal endoscopy screening. Use of all the modalities was strongly influenced by contact with a physician and by having health insurance coverage.

CONCLUSIONS

There remain large gaps in use for all screening modalities by education, income, usual source of care, health insurance, and recent physician contact. These specific populations would benefit from interventions to overcome these barriers to screening.

Impact of PSA testing and prostatic biopsy on cancer incidence and mortality: comparative study between the Republic of Ireland and Northern Ireland

OBJECTIVES

To investigate the impact of different PSA testing policies and health-care systems on prostate cancer incidence and mortality in two countries with similar populations, the Republic of Ireland (RoI) and Northern Ireland (NI).

METHODS

Population-level data on PSA tests, prostate biopsies and prostate cancer cases 1993-2005 and prostate cancer deaths 1979-2006 were compiled. Annual percentage change (APC) was estimated by joinpoint regression.

RESULTS

Prostate cancer rates were similar in both areas in 1994 but increased rapidly in RoI compared to NI. The PSA testing rate increased sharply in RoI (APC = +23.3%), and to a lesser degree in NI (APC = +9.7%) to reach 412 and 177 tests per 1,000 men in 2004, respectively. Prostatic biopsy rates rose in both countries, but were twofold higher in RoI. Cancer incidence rates rose significantly, mirroring biopsy trends, in both countries reaching 440 per 100,000 men in RoI in 2004 compared to 294 in NI. Median age at diagnosis was lower in RoI (71 years) compared to NI (73 years) (p < 0.01) and decreased significantly over time in both countries. Mortality rates declined from 1995 in both countries (APC = -1.5% in RoI, -1.3% in NI) at a time when PSA testing was not widespread.

CONCLUSIONS

Prostatic biopsy rates, rather than PSA testing per se, were the main driver of prostate cancer incidence. Because mortality decreases started before screening became widespread in RoI, and mortality remained low in NI, PSA testing is unlikely to be the explanation for declining mortality.

Prostate-specific antigen screening in the United States vs in the European Randomized Study of Screening for Prostate Cancer-Rotterdam

Dissemination of prostate-specific antigen (PSA) testing in the United States coincided with an increasing incidence of prostate cancer, a shift to earlier stage disease at diagnosis, and decreasing prostate cancer mortality. We compared PSA screening performance with respect to prostate cancer detection in the US population vs in the Rotterdam section of the European Randomized Study of Screening for Prostate Cancer (ERSPC-Rotterdam). We developed a simulation model for prostate cancer and PSA screening for ERSPC-Rotterdam. This model was then adapted to the US population by replacing demography parameters with US-specific ones and the screening protocol with the frequency of PSA tests in the US population. We assumed that the natural progression of prostate cancer and the sensitivity of a PSA test followed by a biopsy were the same in the United States as in ERSPC-Rotterdam. The predicted prostate cancer incidence peak in the United States was then substantially higher than the observed prostate cancer incidence peak (13.3 vs 8.1 cases per 1000 man-years). However, the actual observed incidence was reproduced by assuming a substantially lower PSA test sensitivity in the United States than in ERSPC-Rotterdam. For example, for nonpalpable local- or regional-stage cancers (ie, stage T1M0), the estimates of PSA test sensitivity were 0.26 in the United States vs 0.94 in ERSPC-Rotterdam. We conclude that the efficacy of PSA screening in detecting prostate cancer was lower in the United States than in ERSPC-Rotterdam.

Investigating Black-White differences in prostate cancer prognosis: A systematic review and meta-analysis

The case-fatality rate following a diagnosis of prostate cancer is higher for Black men compared to White men. How this elevated rate arises is uncertain, with differences in disease biology, presentation, treatment and comorbidity having been suggested. A systematic search was conducted for articles that reported ethnic differences in overall-survival, prostate cancer specific survival (PSS) or biochemical recurrence. 48 articles met the inclusion criteria. Black men had worse overall survival (risk ratio 1.35, 95% CI 1.23-1.48) but this was not due to comorbidity alone as PSS and risk of biochemical recurrence were also elevated (1.29, 95% CI 1.13-1.47 and 1.34, 95% CI 1.23-1.46, respectively). Studies adjusting for clinical predictors and socioeconomic variables no longer supported a difference in overall survival (1.01, 95% CI 0.88-1.16), but continued to find an increased risk amongst Black men for PSS (1.13, 95% CI 1.00-1.27) and biochemical recurrence (1.25, 95% CI 1.11-1.41). Similar results were seen for studies from the pre-PSA era and free-health care settings. In contrast to others, studies of metastatic cancer did not find evidence of Black-White differences (p for interaction = 0.01). In conclusion, Black men had a poorer prognosis which was not fully explained by comorbidity, PSA screening, or access to free health care, although few studies measure these factors well. Either management differences for local disease and/or biological differences may be behind Black-White differences in prostate cancer prognosis.

Determinants of prostate cancer stage in northern New England: USA Franco-American contextual effects

Despite screening for prostate cancer, mortality in the United States remains substantial. In northern New England, we know little about either determinants of stage at diagnosis--an important predictor of survival--or health outcomes for Franco-Americans, the region's largest ethnic minority. The objective of this investigation was to identify predictors of late prostate cancer stage in a rural, predominantly white state with a large Franco-American population. The Maine Cancer Registry provided incident cases from 1995 to 1998. We modeled individual-level variables (age, sex, race, French ethnicity by surname, and payer) and contextual/town-level variables (socioeconomic measures, population density, Franco ancestry proportion, distance to health care, and weather severity) with multiple logistic regression for late stage. We found that age categories 50-64, 65-74, and 75-84 years--but not 40-49 years--(versus 85+) were protective for late stage, as was residence in higher snowfall areas. Diagnosis in the earlier years of the study, particularly for French-surnamed men, and residence in a high-Franco area conferred greater risk for late disease. However, in a two-way interaction, residence in towns with high Franco ancestry proportion protected French-surnamed men (OR=0.09, type 3 p<0.0593). Using an established framework for social network theory we explore the potential reasons for this interaction, including: high social cohesion, a wide range of strong ties of long duration, and frequent contact, which might have facilitated access to resources as well as social support and normative influences toward health care seeking. The absence of an association of cancer stage with socioeconomic variables may stem from the mixed sociodemographic profiles in rural and urban regions of Maine. We feel that further research should therefore refine these and other contextual measures to elucidate effects on preventable morbidity and mortality; expand our knowledge of Franco-American health outcomes and social networks; and evaluate the utility of assigning French ethnicity by surname.

Reconstructing PSA testing patterns between black and white men in the US from Medicare claims and the National Health Interview Survey

BACKGROUND

Frequencies of prostate-specific antigen (PSA) test administration were not actively monitored on a national level during the first decade of PSA testing. The objectives of this article were to reconstruct patterns of PSA testing between black and white men in the US and to determine the extent of any racial disparity in PSA use.

METHODS

Data from the 2000 National Health Interview Survey were used to model the adoption of PSA and to estimate the distribution of age at first test. Longitudinal Medicare claims data were used to estimate the distribution of intervals between tests. The rates of initial and subsequent tests were then combined by simulation to reconstruct individual screening histories. Results are from the reconstructed model.

RESULTS

Overall, 45% of white men and 43% of black men within ages 40-84 years had at least 1 PSA test by the year 2000. The authors found that among older men, whites adopted PSA screening earlier than blacks, whereas among younger men, this trend was reversed, with blacks adopting screening earlier than whites. Annual testing frequencies generated by the simulation model were higher for white men aged>or=60 years and higher for black men aged<60 years.

CONCLUSIONS

Findings indicated fairly similar patterns overall of PSA testing for blacks and whites. These similarities indicated that racial disparity in PSA testing is probably not a major factor behind current racial differences in prostate cancer mortality rates and declines. Knowledge of patterns of screening is important to an understanding of the impact of population screening on cancer incidence and mortality, but retrospective data sources have significant limitations when used to estimate these patterns of care.

Prostate cancer specific mortality in the Florence screening pilot study cohort 1992–1993

The impact of screening on prostate cancer mortality is still unknown. A favourable impact is suggested by uncontrolled and possibly biased studies. Mortality from all causes and from prostate cancer was assessed in a cohort of 6,861 males aged 60-74 years, participants to a pilot screening study during 1991-1994. Observed/expected mortality was determined by linkage with cancer and mortality registries. Prostate cancer standardised mortality rate (SMR) in the overall series (751 subjects excluded by GPs for disabling illness or prostate cancer; 3,448 refusers, 2,662 attenders; 67,321.2 men-year) was 0.96 (95% confidence interval (CI)=0.74-1.22) when deaths from prevalent cancers diagnosed before screening were considered. Reduced prostate cancer mortality (SMR=0.48; 95% CI=0.26-0.83), persisting beyond five years after study entry (SMR=0.48; 95% CI=0.22-0.90), was observed in attenders and not in refusers (SMR=0.99; 95% CI=0.69-1.37). This finding might suggest a screening effect, but might also be ascribed to an healthy screening effect, and cannot be assumed as a reliable evidence of screening efficacy.

The evolution of the population-based cancer registry

The idea of recording information on all cancer cases in defined communities dates from the first half of the twentieth century, and there has been a steady growth in the number of such cancer registries since. Originally, they were concerned primarily with describing cancer patterns and trends. Later, many were able to follow up the registered patients and calculate survival. In the last 20 years the role of registries has expanded further to embrace the planning and evaluation of cancer control activities, and the care of individual cancer patients. This Review looks at the current status of cancer registration practice and use from an international perspective, mindful that the registration of cancer has expanded into a global activity.

Population-based screening for prostate cancer by measuring free and total serum prostate-specific antigen in Iran

PURPOSE

To evaluate the natural background of prostate cancer in Iran a large population-based study of screening using total prostate-specific antigen (tPSA) and per cent free PSA (fPSA) as the initial test was performed.

MATERIALS AND METHODS

For 9 years (1996 to 2004) in Tehran, Iran, 3670 Iranian men older than 40 years were mass checked by PSA-based screening. They were invited to have a digital rectal examination (DRE), serum PSA assay and transrectal ultrasonography (TRUS)-guided sextant prostate biopsy to see if the DRE was clinically suspicious of malignancy, the serum PSA was > or =2.1 ng/ml or free-to-total PSA (f/tPSA) ratio < or=15%.

RESULTS

In 433 (11.8%) of screened males, tPSA levels exceeded the cut-off value of > or =2.1 ng/ml and 128 prostate cancers were diagnosed [positive predictive value (PPV) 29.6%] corresponding to an overall detection rate of 3.5%. Altogether 138 cancers were detected (detection rate 3.8%); none were stage M(1), three were stage N(+) and 4 stage T(3). A threshold tPSA of > or =2.1 ng/ml would have detected 128 cancers in 447 biopsied men (PPV 29%). There were 109 of 138 (79%) men with cancer who had an f/tPSA of < or =15%, while 152 of 305 (49.8%) with benign biopsies had a f/tPSA of < or =15%, which corresponds to a PPV of 30.8%.

CONCLUSION

PSA-based screening with low PSA cut-off values increase the detection rate of clinically significant, organ confined and potentially curable prostate cancer. Further studies are warranted in order to determine the incidence and prevalence of prostate cancer in different ethnic groups.

Decision making in prostate-specific antigen screening National Health Interview Survey, 2000

BACKGROUND

The net benefits and harms of prostate cancer screening with the prostate-specific antigen (PSA) test are uncertain, and professional organizations recommend that physicians discuss these uncertainties with patients before initiating screening. Using a nationally representative sample of men reporting past PSA screening, we aimed to determine the extent to which screening was initiated by physicians and preceded by physician-patient discussions.

METHODS

Cross-sectional analysis of data from the 2000 National Health Interview Survey; 2,676 men aged 40 and older underwent PSA screening and met study inclusion criteria. We analyzed the proportions of men for whom PSA screening was (1) was initiated by the physician versus the patient, and (2) preceded by discussions about the test's advantages and disadvantages.

RESULTS

Overall, 74% (95% CI=71.8-76.0) of recipients reported that PSA screening was initiated by their physician, and the proportion increased with advancing age, declining health status, lack of family history of prostate cancer, presence of a usual source of medical care, and non-Hispanic ethnicity. Sixty-five percent (95% CI=63.1-67.1) of screening recipients reported prescreening discussions with their physicians. Discussions were more common with physician-initiated screening than with patient-initiated screening, and among patients reporting a usual source of medical care, non-blue-collar occupation, and black race.

CONCLUSIONS

Among U.S. men receiving PSA screening, screening is usually initiated by physicians, frequently in men relatively less likely to benefit from it, and often without prior discussion of the test's advantages and disadvantages. Further examination of the PSA decision-making process among screened and unscreened men is warranted.

The increased rate of prostate specific antigen testing has not affected prostate cancer presentation in an inner city population in the UK

OBJECTIVE

To assess whether the increased use of prostate-specific antigen (PSA) testing over the last 15 years has changed the way prostate cancer presents in an inner city UK population, where PSA screening rates might be expected to be lower than in epidemiological studies based in North America, where there is a significant tendency to a localized stage and earlier age at diagnosis.

PATIENTS AND METHODS

The study comprised a 5-year retrospective and 5-year prospective analysis of data on 704 men diagnosed with prostate cancer over the 10-year period since the introduction of PSA testing (1994-2003).

RESULTS

The median (range) age at presentation remained unchanged, at 72 (45-94) years; the PSA level at diagnosis was 20-46 microg/L, with a steady decline after 1997. There was no significant change in stage at diagnosis; overall, 38 (20-44)% presented with clinically localized disease, 37 (31-48)% with locally advanced and 25 (18-29)% with metastatic disease. The Gleason grade changed significantly, with more moderately differentiated tumours and a decline in well-differentiated cancers. Closer examination showed this to have been due to a change in diagnostic practice rather than a true population trend. PSA testing increased over the 10 years of the study (2.35 times), with requests from general practitioners rising seven times, compared with urologists or other hospital doctors (1.25 and 2.3 times, respectively). Community PSA testing remained lower than in other reported UK series, which may be explained in part by the lower socio-economic status of the population assessed.

CONCLUSION

There was no apparent change in patient age or tumour stage in men presenting with prostate cancer over a 10-year period after the introduction of PSA testing. While there was an increase in PSA testing during the study period, the testing rate remains much lower than in other reported series from the UK.

Racial/ethnic patterns in lifetime and age-conditional risk estimates for selected cancers

BACKGROUND

Estimates of the probability of developing or dying from cancer, either over a lifetime or over a specified number of years, are useful summary measures of the burden of cancer in a population.

METHODS

The authors used publicly available DevCan software and new, detailed, racial/ethnic data bases that were developed in the Surveillance Research Program of the National Cancer Institute to produce risk estimates for selected major cancers among American Indian/Aleut/Eskimo, black, Chinese, Filipino, native Hawaiian, Japanese, white (total, non-Hispanic), and Hispanic populations.

RESULTS

Japanese and non-Hispanic white men had the highest lifetime risk for developing cancer (47.94% and 47.41%, respectively), and the American Indian/Eskimo/Aleut population (excluding Alaska) had the lowest lifetime risk among men (24.30%). Among women, white and American Indian/Eskimo/Aleut (in Alaska) populations had higher lifetime risks than Japanese women, whereas American Indian/Eskimo/Aleut (excluding Alaska) women had the lowest risk. The age-conditional probabilities of developing cancer within the next 10 years among men and women age 60 years and the lifetime probabilities of dying from cancer also were reported by racial/ethnic group.

CONCLUSIONS

Racial/ethnic disparities in the lifetime risk of cancer may be because of differences in cancer incidence rates, but they also may reflect differential mortality rates from causes other than the cancer of interest. Furthermore, because cross-sectional incidence and mortality rates are used in calculating the DevCan lifetime risk estimates, results must be interpreted with caution when events, such as the widespread and rapid implementation of a new screening test, are known to have influenced disease rates.

Feasibility study using a Ni–Ti stent and electronic portal imaging to localize the prostate during radiotherapy

BACKGROUND AND PURPOSE

A new method for localization of the prostate during external beam radiotherapy is presented. The method is based on insertion of a thermo-expandable Ni-Ti stent. The stent is originally developed for treatment of bladder outlet obstruction caused by benign hyperplasia. The radiological properties of the stent are used for precise prostate localization during treatment using electronic portal images.

PATIENTS AND METHODS

Patients referred for intended curative radiotherapy and having a length of their prostatic urethra in the range from 25 to 65 mm were included. Pairs of isocentric orthogonal portal images were used to determine the 3D position at eight different treatment sessions for each patient.

RESULTS

Fourteen patients were enrolled in the study. The data obtained demonstrated that the stent position was representative of the prostate location. The stent may also improve delineation of the prostate GTV, and prevent obstruction of bladder outlet during treatment. Precision in localization of the stent was less than 1 mm. Random errors in stent position were left-right 1.6 mm, cranial-caudal 2.2 mm and anterior-posterior 3.2 mm. In four of 14 patients a dislocation of the stent to the bladder occurred. Dislocation only occurred in patients with length of prostatic urethra less than 40 mm.

CONCLUSIONS

A new method for radiological high precision localization of the prostate during radiotherapy is presented. The method is based on insertion of a standard Ni-Ti thermo-expandable stent, designed for treatment of benign prostate hyperplasia.

Annual report to the nation on the status of cancer, 1975-2002, featuring population-based trends in cancer treatment

BACKGROUND

The American Cancer Society (ACS), the Centers for Disease Control and Prevention (CDC), the National Cancer Institute (NCI), and the North American Association of Central Cancer Registries (NAACCR) collaborate annually to provide information on cancer rates and trends in the United States. This year's report updates statistics on the 15 most common cancers in the five major racial/ethnic populations in the United States for 1992-2002 and features population-based trends in cancer treatment.

METHODS

The NCI, the CDC, and the NAACCR provided information on cancer cases, and the CDC provided information on cancer deaths. Reported incidence and death rates were age-adjusted to the 2000 U.S. standard population, annual percent change in rates for fixed intervals was estimated by linear regression, and annual percent change in trends was estimated with joinpoint regression analysis. Population-based treatment data were derived from the Surveillance, Epidemiology, and End Results (SEER) Program registries, SEER-Medicare linked databases, and NCI Patterns of Care/Quality of Care studies.

RESULTS

Among men, the incidence rates for all cancer sites combined were stable from 1995 through 2002. Among women, the incidence rates increased by 0.3% annually from 1987 through 2002. Death rates in men and women combined decreased by 1.1% annually from 1993 through 2002 for all cancer sites combined and also for many of the 15 most common cancers. Among women, lung cancer death rates increased from 1995 through 2002, but lung cancer incidence rates stabilized from 1998 through 2002. Although results of cancer treatment studies suggest that much of contemporary cancer treatment for selected cancers is consistent with evidence-based guidelines, they also point to geographic, racial, economic, and age-related disparities in cancer treatment.

CONCLUSIONS

Cancer death rates for all cancer sites combined and for many common cancers have declined at the same time as the dissemination of guideline-based treatment into the community has increased, although this progress is not shared equally across all racial and ethnic populations. Data from population-based cancer registries, supplemented by linkage with administrative databases, are an important resource for monitoring the quality of cancer treatment. Use of this cancer surveillance system, along with new developments in medical informatics and electronic medical records, may facilitate monitoring of the translation of basic science and clinical advances to cancer prevention, detection, and uniformly high quality of care in all areas and populations of the United States.

Prostate cancer incidence in relation to time windows of exposure to metalworking fluids in the auto industry

BACKGROUND

Exposure to metalworking fluids has been previously associated with prostate cancer mortality in a cohort of autoworkers. Our objective was to further explore this finding in a study of prostate cancer incidence in the same cohort, with reduced misclassification of outcome.

METHODS

We conducted a nested case-control study in the General Motors cohort of autoworkers. Incident cases of prostate cancer (n = 872) were identified via the Michigan Cancer Registry from 1985 through 2000. Controls were selected using incidence-density sampling with 5:1 ratio. Using cumulative exposure (mg/m-years) as the dose metric, we first examined varying lengths of lags (0-25 years). Then, we evaluated consecutive windows of exposure: 25 or more years before risk age, and fewer than 25 years. We used penalized splines to model the relative risk as a smooth function of exposure, and adjusted for race and calendar year of diagnosis in a Cox model.

RESULTS

Risk of prostate cancer increased with exposure to soluble and straight fluids 25 years or more before risk age but not with exposure in the last 25 years. The relationship with soluble fluids was piecewise linear, with a small increase in risk at lower exposures followed by a steeper rise. By contrast, the relationship with straight fluids was linear, with a relative risk of 1.12 per 10mg/m-years of exposure (95% confidence interval = 1.04-1.20).

CONCLUSIONS

Exposure to oil-based fluids, soluble and straight, is modestly associated with prostate cancer risk among autoworkers, with a latency period of at least 25 years.

Screening for Prostate Cancer: Opportunities and Challenges

Prostate cancer screening with PSA and with digital rectal examination isa reality in the United States. Regardless of recent observations regarding the complexities of PSA interpretation, millions of U.S. men expect an annual PSA test and physicians have come to rely on the test, in combination with digital rectal examination, to assess for prostate cancer risk. What has become evident is that PSA can no longer be interpreted dichotomously as a simple yes or no. The test reflects a range of risk and PSA value must be merged with other risk factors of an individual man including ethnicity, family history, as well as the individual's risk aversion to complications from prostate cancer. The future of prostate cancer screening will be built upon incorporation of new biomarkers to the prediction of risk of disease. As these markers move forward in testing, it will no longer be acceptable to move these into clinical usage without formal validation studies and, because of the high frequency of prostate cancer in the general male population, these validation studies will almost certainly have to include measures of prognosis. It is the holy grail of cancer biomarker development to acquire a test that is positive in the man with clinically-aggressive prostate cancer but is negative in both the patient without disease and in the man with disease that will be of no clinical consequence over his lifetime.