Economics of Screening for Carcinoma of the Prostate

Evaluation of a rapid one-step PSA test for primary prostate cancer screening

BACKGROUND

To enhance the convenience and reduce the cost of prostate cancer (PC) screening, a one-step prostate-specific antigen (PSA) test was evaluated in a large population. The PSA SPOT test kit enables rapid detection of human PSA in serum or plasma at or above a cutoff level of 4 ng/mL to aid in the diagnosis of PC.

METHODS

PC screening using the PSA SPOT test was offered to male participants in educational public lectures that we conducted in various cities. Test results were reported to participants at the end of the lectures. Blood samples from 1429 men were evaluated. Two independent observers interpreted the tests at 15 and 30 min. The remaining serum samples were subsequently tested using a conventional quantitative assay.

RESULTS

The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the test were 79.9, 93.0, 65.4, 96.6, and 91.2%, respectively. The sensitivity and specificity of the test changed with variations in the reading time. Quantitative assessment of the intensity of the band was correlated with the PSA value.

CONCLUSIONS

PSA testing using this kit can be easily performed. The low cost and speed of the test make it a useful and convenient tool for primary PC screening.

Benefits and harms of prostate cancer screening - predictions of the ONCOTYROL prostate cancer outcome and policy model

Background

A recent recalibration of the ONCOTYROL Prostate Cancer Outcome and Policy (PCOP) Model, assuming that latent prostate cancer (PCa) detectable at autopsy might be detectable by screening as well, resulted in considerable worsening of the benefit-harm balance of screening. In this study, we used the recalibrated model to assess the effects of familial risk, quality of life (QoL) preferences, age, and active surveillance.

Methods

Men with average and elevated familial PCa risk were simulated in separate models, differing in familial risk parameters. Familial risk was assumed to affect PCa onset and progression simultaneously in the base-case, and separately in scenario analyses. Evaluated screening strategies included one-time screening at different ages, and screening at different intervals and age ranges. Optimal screening strategies were identified depending on age and individual QoL preferences. Strategies were additionally evaluated with active surveillance by biennial re-biopsy delaying treatment of localized cancer until grade progression to Gleason score ≥ 7.

Results

Screening men with average PCa risk reduced quality-adjusted life expectancy (QALE) even under favorable assumptions. Men with elevated familial risk, depending on age and disutilities, gained QALE. While for men with familial risk aged 55 and 60 years annual screening to age 69 was the optimal strategy over most disutility ranges, no screening was the preferred option for 65 year-old men with average and above disutilities.

Active surveillance greatly reduced overtreatment, but QALE gains by averted adverse events were opposed by losses due to delayed treatment and additional biopsies. The effect of active surveillance on the benefit-harm balance of screening differed between populations, as net losses and gains in QALE predicted for screening without active surveillance in men with average and familial PCa risk, respectively, were both reduced.

Conclusions

Assumptions about PCa risk and screen-detectable prevalence significantly affect the benefit-harm balance of screening. Based on the assumptions of our model, PCa screening should focus on candidates with familial predisposition with consideration of individual QoL preferences and age. Active surveillance may require treatment initiation before Gleason score progression to 7. Alternative active surveillance strategies should be evaluated in further modeling studies.

The ONCOTYROL Prostate Cancer Outcome and Policy Model: Effect of Prevalence Assumptions on the Benefit-Harm Balance of Screening

BACKGROUND

The ONCOTYROL Prostate Cancer Outcome and Policy (PCOP) model is a state-transition microsimulation model evaluating the benefits and harms of prostate cancer (PCa) screening. The natural history and detection component of the original model was based on the 2003 version of the Erasmus MIcrosimulation SCreening ANalysis (MISCAN) model, which was not calibrated to prevalence data. Compared with data from autopsy studies, prevalence of latent PCa assumed by the original model is low, which may bias the model toward screening. Our objective was to recalibrate the original model to match prevalence data from autopsy studies as well and compare benefit-harm predictions of the 2 model versions differing in prevalence.

METHODS

For recalibration, we reprogrammed the natural history and detection component of the PCOP model as a deterministic Markov state-transition cohort model in the statistical software package R. All parameters were implemented as variables or time-dependent functions and calibrated simultaneously in a single run. Observed data used as calibration targets included data from autopsy studies, cancer registries, and the European Randomized Study of Screening for Prostate Cancer. Compared models were identical except for calibrated parameters.

RESULTS

We calibrated 46 parameters. Prevalence from autopsy studies could not be fitted using the original parameter set. Additional parameters, allowing for interruption of disease progression and age-dependent screening sensitivities, were needed. Recalibration to higher prevalence demonstrated a considerable increase of overdiagnosis and decline of screening sensitivity, which significantly worsened the benefit-harm balance of screening.

CONCLUSIONS

Our calibration suggests that not all cancers are at risk of progression, and screening sensitivity may be lower at older ages. PCa screening models that use calibration to simulate disease progression in the unobservable latent phase are highly sensitive to prevalence assumptions.

Near infrared photonic finger imager for prostate cancer screening

A portable rectal near infrared (NIR) scanning polarization imaging unit with an optical fiber-based rectal probe, designated as a Photonic Finger (PF), was designed, developed, built and tested. PF was used to image and locate the three dimensional (3D) positions of abnormal prostate tissue embedded inside normal prostate tissue. An inverse image reconstruction algorithm, namely Optical Tomography using Independent Component Analysis (OPTICA) was developed to unmix the signal from targets (cancerous tissue) embedded in a turbid media (normal tissue) in the backscattering imaging geometry. The Photonic Finger combined with OPTICA was ex vivo tested to characterize different target(s) inside different tissue medium, including cancerous prostate tissue embedded inside large pieces of normal tissue. This new developed instrument, Photonic Finger, may provide an alternative imaging technique, which is accurate, of high spatial resolution and non-or-less invasive for prostate cancers screening.

Why victory in the war on cancer remains elusive: biomedical hypotheses and mathematical models

We discuss philosophical, methodological, and biomedical grounds for the traditional paradigm of cancer and some of its critical flaws. We also review some potentially fruitful approaches to understanding cancer and its treatment. This includes the new paradigm of cancer that was developed over the last 15 years by Michael Retsky, Michael Baum, Romano Demicheli, Isaac Gukas, William Hrushesky and their colleagues on the basis of earlier pioneering work of Bernard Fisher and Judah Folkman. Next, we highlight the unique and pivotal role of mathematical modeling in testing biomedical hypotheses about the natural history of cancer and the effects of its treatment, elaborate on model selection criteria, and mention some methodological pitfalls. Finally, we describe a specific mathematical model of cancer progression that supports all the main postulates of the new paradigm of cancer when applied to the natural history of a particular breast cancer patient and fit to the observables.

Male BRCA1 and BRCA2 mutation carriers: a pilot study investigating medical characteristics of patients participating in a prostate cancer prevention clinic

BACKGROUND

Male BRCA1 and BRCA2 mutation carriers are at an increased risk to develop prostate cancer and are subject to screening protocols for high-risk men. The utility of targeted screening, and the clinical and pathological features associated with prostate cancer, have received little attention in this population.

METHODS

We report on the clinical screening and pathological characteristics of a group of 19 men with BRCA1 or BRCA2 mutation, as compared to an age-matched group of men with a family history of prostate cancer.

RESULTS

Mutation carriers were significantly more likely to have an elevated PSA at first visit (P = 0.03). Prostate cancer was twice as likely to be diagnosed in mutation carriers although this difference was not statistically significant (P = 0.55).

CONCLUSIONS

Prostate cancer surveillance of BRCA1 and BRCA2 mutation carriers is warranted. Further research on larger cohorts is needed to evaluate whether unique pathological prostate cancer characteristics exist in these men.

Correctable sources of disparities in cancer among minority elders

This article explores the hypothesis that medical policies and procedures represent immediately correctible causes of disparity in minority elders. Evidence of policies and procedures that have the unintended consequence of creating disparity is presented. The text is focused on one site, prostate, as a sample tumor to present a strategy for correcting sources of disparities in cancer morbidity and mortality. Specific prostate cancer issues with unintended effects include the prostate cancer screening controversy, access to diagnostic facilities in minority communities, and special needs of older adult cancer survivors. A summary of all recommendations and their implications across cancer sites is provided.

Reliability and validity of the PORPUS, a combined psychometric and utility-based quality-of-life instrument for prostate cancer

BACKGROUND

Although utility-based quality-of-life instruments are often used in economic evaluations and psychometric instruments in treatment evaluations, these are complementary approaches to assessing outcomes. In this study we developed and tested these two forms of quality-of-life instruments, both based on a single, validated, health classification system.

OBJECTIVES

To assess the measurement properties (reliability and validity) of two newly developed psychometric and utility-based instruments for assessing outcomes associated with prostate cancer.

METHODS

141 men with cancer of the prostate (CaP), treated with radical prostatectomy, radiation therapy, hormonal therapy, and/or chemotherapy were assessed with both instruments and other standard psychometric and utility-based instruments.

RESULTS

Analyses indicate the test instruments are reliable and valid. Full-scale correlations between the instruments and standard instruments indicate validity, as do correlations of key subscales, and an evaluation of linear associations with the UCLA-Prostate Cancer Symptom Scales.

CONCLUSION

Evidence from this study supports the reliability and construct validity of the tested instruments. Prostate cancer outcomes can now be assessed by a combination of psychometric and utility-based methods, allowing a ready comparison of derived outcomes.

Evaluation of a new, rapid, qualitative, one-step PSA Test for prostate cancer screening: the PSA RapidScreen test

To increase the acceptance rate and reduce the cost of the screening programme for prostate cancer, a new qualitative and one-step test for prostate-specific antigen (PSA), called PSA RapidScreen, has been evaluated. PSA RapidScreen test is a chromatographic lateral flow immunoassay, which generates a positive or negative result for PSA values >or=or <4 ng/ml, respectively. Capillary blood samples from 188 men were evaluated. Two independent observers interpreted the test at 10, 15, 20 and 25 min. A total of 10 women were tested as controls. Parallel serum samples were simultaneously collected and tested with an ordinary quantitative assay (Elecsys 2010, Roche). Sensitivity, specificity, accuracy, negative and positive predictive values of the test were 97.6, 90.4, 94, 98 and 89%, respectively. PSA RapidScreen tests on female capillary samples were negative. Reproducibility of the test was 99.5%, while interobserver variation was 5%. Specificity of the test was altered by variations in the reading time. Quantitative assessment of the intensity of the band correlated with the PSA value (r=0.87; t=23.97; P<0.001). PSA RapidScreen is a rapid, simple and reproducible one-step test. The low cost and the speed of the test make it a powerful and convenient tool for prostate cancer screening programmes.

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.

The economic costs of early stage prostate cancer

The economic costs of early stage prostate cancer are significant, and will likely increase as the proportion of older men grows in the population of industrialised nations. In the US, total costs have been estimated to range from US dollars 1.72 billion to US dollars 4.75 billion annually (1990 costs). Costs related to early stage prostate cancer arise from screening, staging and treatment. Cost-effectiveness models of population-based prostate cancer screening indicate that such screening could result in as much as US dollars 27.9 billion (1988 values) in charges to the US healthcare system. Evidence-based cancer-staging strategies would result in significant reduction of wasted expense. Rational allocation of healthcare dollars for prostate cancer screening and treatment may ultimately depend on data from randomised controlled trials.

Prostate cancer: screening and early detection

BACKGROUND

Despite more than a decade of prostate-specific antigen (PSA)-based screening, the proven impact of screening on mortality due to prostate cancer continues to be controversial.

METHODS

A literature review of issues pertaining to the epidemiology, screening, early detection, and mortality as they relate to prostate cancer was conducted. Included in the review are PSA refinements, controversies of screening, and organization guidelines. Finally, recent reports of mortality rates in the post-PSA era are presented for discussion.

RESULTS

Prostate cancer mortality rates have begun to decline for the first time since statistics have been recorded. The recent decline in age-adjusted mortality rates from prostate cancer is significant, and this decline appears to be earlier than would have been predicted. This finding, coupled with the dramatic decline in metastatic disease, implies that PSA-based screening may be responsible for a significant portion of this improvement in mortality.

CONCLUSIONS

The cost of prostate cancer screening appears to be acceptable. Randomized studies of PSA-based screening are currently ongoing, although the results may not be available for a decade. Currently, the best evidence is derived from population-based studies that appear to show a benefit to prostate cancer screening.

Serial prostate specific antigen screening for prostate cancer: a computer model evaluates competing strategies

PURPOSE

We compare prostate specific antigen (PSA) screening strategies in terms of expected years of life saved with screening, number of screens, number of false-positive screens and rates of over diagnosis, defined as detection by PSA screening of patients who would never have been diagnosed without screening.

MATERIALS AND METHODS

A computer model of disease progression, clinical diagnosis, PSA growth and PSA screening was used. Under baseline conditions, when screening is not considered, the model replicates clinical diagnosis and disease mortality rates recorded by the Surveillance, Epidemiology and End Results Program of the National Cancer Institute in the mid 1980s.

RESULTS

Biannual screening with PSA greater than 4.0 ng./ml. was projected to reduce the number of screens and false-positive tests by almost 50% relative to annual screening while retaining 93% of years of life saved. With annual screening use of an age specific bound for PSA to consider a test positive instead of the standard 4.0 ng./ml. was projected to reduce false-positive screens by 27% and over diagnosis by a third while retaining almost 95% of years of life saved. Sensitivity analyses did not change the relative efficacy of biannual screening.

CONCLUSIONS

Under the model assumptions biannual PSA screening is a cost-effective alternative to annual PSA screening for prostate cancer. With annual screening use of an age specific bound for PSA positivity appears to reduce false-positive results and over diagnosis rates sharply relative to a bound of 4 ng./ml. while retaining most of the survival benefits.

Correlates of dissatisfaction with treatment in patients with prostate cancer diagnosed through screening

PURPOSE

We evaluated correlates of patient reported dissatisfaction with treatment of prostate cancer detected by screening.

MATERIALS AND METHODS

We performed a cross-sectional retrospective study to evaluate the correlates of dissatisfaction with treatment in 1,651 patients in whom prostate cancer was detected through serial screening. We included demographic and clinical characteristics in the independent and control variables, and we validated measurements of quality of life outcomes.

RESULTS

Overall 11% of patients were dissatisfied with the treatment received. Differences in the rates of dissatisfaction with treatment were not statistically significant across treatment groups (11% for retropubic radical prostatectomy, 21% for perineal radical prostatectomy, 14% for radiotherapy, 8% for observation, 8% for hormonal treatment and 4% for cryoablation, p = 0.1). Patient age, race, followup interval, marital status, education and co-morbid conditions were not significant correlates of dissatisfaction with treatment (for all characteristics p> or =0.05). Urinary function and bothersomeness were associated with dissatisfaction with treatment (p<0.0001), whereas sexual function and bothersomeness were not (p>0.05). Multivariate analysis revealed that urinary function and bothersomeness were also the only significant correlates of dissatisfaction with treatment.

CONCLUSIONS

Of patients in whom prostate cancer was detected by screening 11% were dissatisfied with treatment. Urinary function and bothersomeness were the only important correlates of dissatisfaction.

Neutralizing anti-vascular endothelial growth factor antibody completely inhibits angiogenesis and growth of human prostate carcinoma micro tumors in vivo

BACKGROUND

Neovascularization mediated by growth factors produced by tumors is critical for the growth of tumors. Vascular endothelial growth factor (VEGF) is one such growth factor. A neutralizing anti-VEGF antibody (A4.6.1) was recently shown in vivo to inhibit tumor angiogenesis and growth of the human rhabdomyosarcoma cell line A673. The antibody profoundly changed the growth characteristics of the tumor line from a rapidly growing malignancy to a dormant microcolony.

METHODS

In the present study, we evaluated the effects of A4.6.1 (100 microg twice weekly, i.p.) on growth and angiogenic activity of spheroids of the human prostatic cell line DU 145 (diameter 700 microm at implantation) implanted in dorsal skinfold chambers in nude mice (n = 11). An antibody of the same isotype (n = 5) or saline (n = 5) was used as control. Tumor cells were prelabeled with a fluorescent vital dye (CMTMR), which allowed measurement of size of the implanted tumor spheroids throughout a two week observation period. FITC-dextran was used for plasma enhancement to visualize angiogenic activity.

RESULTS

Tumors of control animals induced a neo-vasculature with high vascular density (350+/-12 cm[-1]). In animals treated with the anti-VEGF antibody, there was complete inhibition of neovascularization of the micro tumors and complete inhibition of tumor growth after the initial prevascular angiogenesis independent growth phase.

CONCLUSIONS

These results demonstrate that inhibition of the key regulatory paracrine growth factor for endothelial cells, VEGF, results in complete suppression of prostate cancer induced angiogenesis and prevents tumor growth beyond the initial prevascular growth phase.

Cancer of the prostate. 3: Men's healthcare needs

This article, the third in a three-part series, addresses the complex issues surrounding screening for prostate cancer. The purpose of screening in health care is discussed and the advantages and disadvantages of the various screening tests for the early detection of prostate cancer are outlined. The use of one specific technique to screen men for prostate cancer is questioned. It is suggested that several techniques should be used to assess risk in detail. Employing only one technique, for example prostate specific antigen, may result in men undergoing unnecessary surgery or inappropriate treatment. Nurses have a professional duty to ensure that they are aware of the advantages and disadvantages with respect to screening men for cancer of the prostate. Patients' must be in possession of the facts before they make important decisions about their health. In order to reduce harm the nurse can become the patient's advocate and act in such a way as to safeguard and promote the patient's interests.

The dilemma of prostate cancer--a growing human and economic burden irrespective of treatment strategies

All prostate cancer patients (719 patients) within a specified population were studied in order to assess both the overall economic burden of this disease to the health-care economy and its burden to the individual patient. The economic burden was estimated as the total lifetime expense (1995 prices) of all palliative hospital treatment. The expenses associated with prostate cancer therapy averaged US$ 19755 per person. By extrapolation, palliative therapy for this disease currently consumes almost 1% of the entire Danish health-care budget. A total of 62% of the patients died from the disease. During hospitalization these patients on average required three times as much hospital care as other patients and about one-third needed regular treatment with opiates or equivalent drugs. Under the present circumstances we cannot recommend an aggressive strategy towards localized prostate cancer even though the incidence of this disease is increasing at an alarming speed and its economic and human costs are excessive.

Prostate-specific antigen-detected prostate cancer (stage T1c): an analysis of whole-mount prostatectomy specimens

BACKGROUND

Clinical and pathological staging of prostate cancer has been, and remains, problematic. Since prostate-specific antigen (PSA)-detected tumors are often discerned during "screening," what are their significance?

METHODS

We analyzed 67 consecutive patients with stage T1c prostate cancer undergoing radical prostatectomy at our institution from August 1, 1991-September 12, 1995, and who had whole-mount specimen processing. Diagnosis was determined in all cases by transrectal ultrasound-guided biopsy.

RESULTS

The mean age of our patients was 63 years, and the mean PSA at time of diagnosis was 8.6 ng/ml (median, 7.2 ng/ml). There was organ-confined cancer in 31/67 (46%) patients; 17/67 (25%) had periprostatic fat infiltration, and of these 5(7%) had seminal vesicle involvement. Thirty-one of 67 (46%) had positive surgical margins. Twenty-two (33%) had a Gleason sum of > or = 7 in the final pathological specimen. Insignificant tumors (dominant tumor volume < 0.20 cc) were found in only 4 cases. Smaller tumors were more likely to be found when the PSA was < 10 ng/ml. Multifocal disease was found in 64/67 (96%) prostate specimens.

CONCLUSIONS

This study adds impetus to the growing realization that nonpalpable prostate cancer, detected because of elevated PSA, is rarely insignificant. Our findings add further emphasis to the fact that patients diagnosed by PSA elevation have, for the most part, significant cancer that should be treated aggressively.

Discussion of the controversies associated with prostate cancer screening

Early detection of prostate cancer through screening seems to provide the best hope of control or possibly cure of the disease. Unfortunately, controversy and confusion surround the screening guidelines. Specifically, the controversy involves whether the screening of asymptomatic men, particularly those under age 50, should be recommended. To date, there have been no randomised clinical trials which have demonstrated that screening for prostate cancer reduces mortality or increases life expectancy. The lack of evidence regarding the benefits of prostate screening and the risk of adverse effects make it important for clinicians to provide information to interested patients regarding the possible consequences before they take part in screening endeavours. Other health care professionals must be proactive in becoming informed about the entire prostate screening issue.

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.

Screening for prostate cancer is neither appropriate nor cost-effective

Seen from a societal perspective, the health gains that might result from prostate screening are too uncertain to justify the substantial associated costs and adverse health effects. Clinicians who rely on observational screening studies to justify current screening practices should be aware of the potential biases that render conclusions suspect. Medical history documents numerous cases of medical interventions that appeared reasonable at the time, but ultimately proved worthless and even harmful. Before embarking on an ambitious screening program for prostate cancer, clinicians should demand that five basic criteria are satisfied: (1) that prostate cancer is a significant health burden, (2) that screening can identify localized disease, (3) that tests used in screening programs have acceptable performance among the population being tested, (4) that the potential for cure is greater among patients with screen-detected disease, and (5) that screen-detected patients have improved health outcomes compared with those who are not screened. Randomized trials provide the best methodology for determining the efficacy of screening and treatment. Clinicians are often too quick to credit medical intervention for successful outcomes and blame tumor biology for disease progression. Furthermore, when faced with a decision of administering or withholding therapy, physicians generally wish to err on the side of having done everything possible. Data modeling can provide critical insights concerning these issues using currently available information. Three recently published models suggest that the overall benefit to a population of men screened for prostate cancer can be measured in days of additional time of life gained, not months or years. Furthermore, models suggest that a substantial number of men need to undergo treatment in order to avert a single cancer death. The costs of implementing a screening program are enormous and deflect resources away from alternative uses, such as increased basic science funding to identify a cure for this disease. Therefore, based on the evidence presented, I believe that without more substantial data supporting the efficacy of screening programs, screening for prostate cancer is neither appropriate nor cost-effective.

Accuracy of prostate volume measurements in vitro using three-dimensional ultrasound

RATIONALE AND OBJECTIVES

We assessed the ability of a three-dimensional (3D) ultrasound imaging system to measure accurately prostate volume.

METHODS

Multiple two-dimensional ultrasound images of cadaver prostates scanned in a water bath were reconstructed into three-dimensional (3D) images. The volumes of the prostates were calculated from these 3D images and compared with the actual volumes. Multiple 3D ultrasound volume readings were evaluated for precision.

RESULTS

The slope of the best-fit line correlating 3D ultrasound estimated volume and true volume was 1.006 +/- 0.007. The average error was 0.36 +/- 1.17 cm3; the coefficient of determination (r2), which is the measure of the straight-line relationship, was .9997; and the standard error was 1.15 cm3.

CONCLUSION

Three-dimensional ultrasound images accurately reflect true prostate volumes measured in vitro.

Prostate-specific antigen in mass screening for carcinoma of the prostate

BACKGROUND

Prostate-specific antigen (PSA) has various advantages over prostatic acid phosphatase (PAP) as a marker for prostate cancer, but its role in prostate cancer mass screening remains controversial. We measured serum PSA in addition to serum PAP determination and digital rectal examination (DRE) in our mass screening program to assess the usefulness of PSA for prostate cancer mass screening.

METHODS

Serum PSA and PAP measurements and DRE were performed in 1249 patients in mass screening for carcinoma of the prostate in 1989 and 1990. Thirteen cancers were diagnosed. We calculated the mean plus standard deviations (2SD) of the PSA and PAP values of men without cancer, and assessed the usefulness of PSA for prostate cancer screening by using these figures as the upper limit of normal.

RESULTS

The number positive for PSA, PAP and DRE were 39, 36 and 48, respectively. If our screening had been performed without DRE, three cancers would have remained undetected, and the number would have been the same if performed without PSA. If the screening had been performed without PAP, on the other hand, no cancers would have remained undetected. The sensitivities of PSA and PAP were 54% and 23%, respectively. The screening detection rate with DRE and PSA was 0.88%, and with DRE and PAP was 0.64%.

CONCLUSIONS

Measurement of serum PSA values with adjustment of the cut-off value was considered more useful than PAP in mass screening for prostate cancer.

Ruolo dell'ER e del PSA nello screening per la diagnosi precoce del carcinoma prostatico:The role of ER and PSA in screening for early diagnosis of prostatic carcinoma

From September 1992 to February 1994, 1441 men aged between 50 and 70 years underwent screening with PSA and ER measurement for early diagnosis of prostatic carcinoma. A neoplasm was diagnosed in 1.73% (25/1441) of cases, which being found at an early stage, made it possible to perform prostatectomy and radical radiotherapy on 37.5% and 16.6% of patients respectively. The incidence of the disease was higher than in a previous screening with just ER dosage (1.73% vs 1.1%). Combined PSA and ER also gave higher sensitivity, specificity, overall accuracy and predictiveness compared to the methods taken individually. This combination seems preferable, in view of the greater efficacy and “practicability” compared to protocols which involve the use of USTR, which is less practicable on a large scale due to the length of time required and high costs. The utility of periodic determination of PSA levels in those over fifty years old is emphasised, both for oncological screening controls and to increase the diagnostic accuracy of other clinical tests.

Clinical and biological aspects of acid phosphatase

The identity and genetic origins of the nonspecific orthophosphate monoesterases with an acid pH optimum--the acid phosphatases--are now becoming clear. They form a family of genetically distinct isoenzymes, many of which show significant posttranslational modification. Four true isoenzymes exist. The erythrocytic and lysosomal forms show widespread distribution and are expressed in most cells; in contrast, the prostatic and macrophagic forms have a more limited expression. The erythrocytic and macrophagic forms are distinguished from the others in resisting inhibition by dextrorotatory tartrate. The prostatic form has long been used as a marker for prostatic cancer and the macrophagic forms have been linked with miscellaneous disorders, notably increased osteolysis, Gaucher's disease of spleen, and hairy cell leukemia, whereas the normal levels of intravesical lysosomal acid phosphatase in I cell disease pointed the way toward the mechanisms underlying its intracellular processing.

The use of prostate specific antigen for prostate cancer screening: a managed care perspective

A large nonprofit staff model Health Maintenance Organization experienced increased use of prostate specific antigen (PSA) as a screening test for prostate cancer beginning in May 1991. A critical evaluation of the evidence in support of PSA screening was done and concluded that the use of PSA to screen for prostate cancer did not meet the criteria for an effective screening program. A guideline stating that PSA was not recommended as a screening test was implemented focusing on a model of shared decision making. PSA test ordering decreased significantly when patients were fully informed about the evidence for PSA screening. If PSA screening had continued at the peak rate, the cascade of intervention initiated by screening would have resulted in significant complications and approximately $4,800,000 in increased costs.

Cost analyses of prostate cancer screening: frameworks for discussion. Investigators of the American Cancer Society-National Prostate Cancer Detection Project

Our recent cost analysis of prostate cancer early detection evaluated the economic performance of various prostate specific antigen (PSA) screening approaches, detected marginal cost variations with time and used a benefit-cost calculation as a framework for further discussion. Receiver operator characteristic analysis initially suggested an optimal test performance for PSA of 2 to 3 ng./ml. when used alone and at approximately 3 ng./ml. in combination with digital rectal examination. However, lower PSA decision levels require cost justifications. Marginal cost analysis demonstrated markedly decreased use of digital rectal examination by year 3 due to significantly lower sensitivity for incident cancer. The benefit-cost equation acknowledges that many parameters of cost and probability are not definitive to date yet illustrated major points for discussion. The cost parameters most sensitive to incremental change in decreasing order are the specificity of the screening test, benefits obtained from early therapy and prevalence of the disease. Discussions about improving the likelihood of overall benefit for the United States population should focus on these parameters, as well as social and ethical implications. If we assume minimized future expenditures for terminal cancer care via decreases in therapy choices or coverage, no economic benefit for screening exists. If we also assume that potential costs to society are not roughly approximated by any benefits, we may engender inappropriate attempts at cost reduction by effectively discouraging screening in the highest risk groups. Perhaps the greatest immediate cost control issue is the marked increase in prostate cancer detection in the oldest age groups who have the least likelihood of mortality or morbidity benefits. Current cost savings may be possible with improved public health education about the appropriateness of early detection in the oldest age groups or those with significant preexisting medical conditions.

Prostate cancer screening. Appropriate choices? Investigators of the American Cancer Society National Prostate Cancer Detection Project

Early detection of prostate cancer has produced distinct stage migration of prostate cancer to earlier, more curable disease through optimized combined use of digital rectal exam (DRE), transrectal ultrasound, and prostate specific antigen (PSA). Currently available and emerging data can be assessed according to the World Health Organization's established criteria. As a significant public health problem, prostate cancer meets almost all the criteria for screening. While concerns about incomplete natural history, progression rates, and the need for better prognostic factors are valid, important social and public health issues also need to be considered. If future expenditures for terminal cancer care are minimized via reductions in therapy choices or coverage, no economic benefit for prostate cancer screening should exist. Narrow-focused attempts at cost reduction could inappropriately discourage high risk groups from participating in early detection programs, thereby eliminating the greatest potential benefit. Conversely, the greatest immediate cost-control issue for prostate cancer care in the United States could be the marked increased detection in men older than 75 years of age. Current cost savings are possible with improved public health education about the appropriateness of early detection in the oldest age groups or those with significant preexisting medical conditions. Prostate cancer control perhaps requires a tailored approach of screening in high risk groups and more appropriate "case finding" in the lower risk, general population. The initial combination of PSA and DRE can result in early detection, which is both ethical and economic, for individual patients consulting with informed physicians.