Evaluation of prostatic specific antigen and digital rectal examination as screening tests for prostate cancer

Comparing the Performance of Digital Rectal Examination and Prostate-specific Antigen as a Screening Test for Prostate Cancer: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVE

Although digital rectal examination (DRE) is recommended in combination with prostate-specific antigen (PSA) for detection of prostate cancer (PCa), there are limited data to support its use as a screening/early detection test. Our objective was to assess the diagnostic value of DRE in screening for early detection of PCa.

METHODS

In August 2023, we queried the PubMed, Scopus, and Web of Science databases to identify prospective studies simultaneously investigating the diagnostic performance of DRE and PSA for PCa screening. The primary endpoints were the positive predictive value (PPV) and cancer detection rate (CDR) of DRE. Secondary endpoints included the PPV and CDR of both PSA alone and in combination with DRE. We conducted meta-regression analysis to compare the CDR and PPV of different screening strategies. This meta-analysis is registered on PROSPERO (CRD42023446940).

KEY FINDINGS AND LIMITATIONS

We identified eight studies involving 85,798 participants, of which three were randomized controlled trials and five were prospective diagnostic studies, that reported the PPV and CDR of both DRE and PSA for the same cohort. Our analysis revealed a pooled PPV of 0.21 (95% confidence interval [CI] 0.13-0.33) for DRE, which is similar to the PPV of PSA (0.22, 95% CI 0.15-0.30; p = 0.9), with no benefit from combining DRE and PSA (PPV 0.19, 95% CI 0.13-0.26; p = 0.5). However, the CDR of DRE (0.01, 95% CI: 0.01-0.02) was significantly lower than that of PSA (0.03, 95% CI 0.02-0.03; p < 0.05) and the combination of DRE and PSA (0.03, 95% CI 0.02-0.04; p < 0.05). The screening strategy combining DRE and PSA was not different to that of PSA alone in terms of CDR (p = 0.5) and PPV (p = 0.5).

CONCLUSIONS AND CLINICAL IMPLICATIONS

Our comprehensive review and meta-analysis indicates that both as an independent test and as a supplementary measure to PSA for PCa detection, DRE exhibits a notably low diagnostic value. The collective findings from the included studies suggest that, in the absence of clinical symptoms and signs, DRE could be potentially omitted from PCa screening and early detection strategies.

PATIENT SUMMARY

Our review shows that the screening performance of digital rectal examination for detection of prostate cancer is not particularly impressive, suggesting that it might not be necessary to conduct this examination routinely.

Comparative Pathobiology of Canine and Human Prostate Cancer: State of the Art and Future Directions

First described in 1817, prostate cancer is considered a complex neoplastic entity, and one of the main causes of death in men in the western world. In dogs, prostatic carcinoma (PC) exhibits undifferentiated morphology with different phenotypes, is hormonally independent of aggressive character, and has high rates of metastasis to different organs. Although in humans, the risk factors for tumor development are known, in dogs, this scenario is still unclear, especially regarding castration. Therefore, with the advent of molecular biology, studies were and are carried out with the aim of identifying the main molecular mechanisms and signaling pathways involved in the carcinogenesis and progression of canine PC, aiming to identify potential biomarkers for diagnosis, prognosis, and targeted treatment. However, there are extensive gaps to be filled, especially when considering the dog as experimental model for the study of this neoplasm in humans. Thus, due to the complexity of the subject, the objective of this review is to present the main pathobiological aspects of canine PC from a comparative point of view to the same neoplasm in the human species, addressing the historical context and current understanding in the scientific field.

MRI for clinically suspected prostate cancer-the disparity between private and public sectors

BACKGROUND

There is increasing evidence to implement multiparametric magnetic resonance imaging (mpMRI) for biopsy-naive men with clinically suspected prostate cancer (PCa). This will reduce the number of unnecessary trans rectal ultrasound biopsies (TRUS-Bx) performed and reduce the number of indolent cancers diagnosed.

AIMS

To assess current clinical practices for investigating clinically suspected prostate cancer in Ireland and determine if private health insurance providers are offering mpMRI scans in biopsy-naive men.

METHODS

Each health insurance provider procedure code was reviewed. The indications and requirements for prostate mpMRI in the setting of diagnosis, staging, surveillance, and recurrence were assessed for each health care provider. Current practices adopted by accredited referral clinics for suspected prostate cancer were reviewed.

RESULTS

Two of the three leading health insurance providers, which between them cover 46% of the private health insurance market in Ireland, provide pre-biopsy mpMRI cover as of April 2019. This leaves almost half of those insured with no accessibility to pre-biopsy mpMRI. This is in contrast to the majority of public NCCP hospitals that offer pre-biopsy mpMRI for clinically suspected prostate cancer.

CONCLUSIONS

Pre-biopsy mpMRI for clinically suspected prostate cancer is emerging as a standard of practice in Ireland. International guidelines are also changing to reflect latest clinical trial evidence. Private health insurance providers should amend their policies to reflect current clinical practices already adopted in the public sector.

Assessment of the influence of transrectal and transperineal prostate biopsies on erectile function: A prospective observational single-center study

OBJECTIVES

To assess the impact of transrectal versus transperineal prostate biopsy on erectile function.

METHODS

This was a single-center, observational, prospective study of consecutive patients who underwent a prostate biopsy (transrectal or transperineal/fusion biopsy). Study participants completed the International Index of Erectile Function-5 questionnaire before the procedure, and 3 and 6 months after. Prostatic biopsies were carried out following the standard procedure for both techniques.

RESULTS

The study included 135 male patients with a mean age of 63.5 years. At baseline, 28 patients (21%) presented normal erectile function, whereas 107 patients (82%) presented erectile dysfunction, which was severe in four (3%), moderate in 49 (36%) and mild in 54 (40%), with an overall mean International Index of Erectile Function-5 score of 17.70. After 3 months, the rates were 29%, 3%, 27% and 38%, respectively (mean International Index of Erectile Function-5 score 17.95). At 6 months, the rates were 30%, 6%, 28% and 34%, respectively (mean International Index of Erectile Function-5 score of 17.77). No significant differences between pre- and post-biopsy International Index of Erectile Function-5 scores at 3 and 6 months were observed, even when analyzing transrectal and transperineal separately. The number of biopsy cores and number of previous biopsies did not influence the International Index of Erectile Function-5 scores.

CONCLUSIONS

Our findings suggest that prostate biopsy technique, number of biopsy cores and history of previous biopsy do not significantly impact erectile function in the medium term up to 6 months.

Role of delayed-time-point imaging during abdominal and pelvic cancer screening using FDG-PET/CT in the general population

Although delayed-time-point imaging is expected to improve the results of [F]-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT), how examinees will benefit from dual-time-point imaging versus initial-time-point imaging alone, remains unclear. This study investigated the role of delayed-time-point imaging in improving the results of abdominal and pelvic cancer screening using FDG-PET/CT.This retrospective review included 3131 screening results (average subject age: 55.5 years, range: 40-88 years). First, 2 nuclear medicine physicians tentatively evaluated whole-body initial-time-point PET/CT scans. Subsequently, delayed-time-point imaging of the abdomen and pelvis was performed approximately 150 min after FDG injection, followed by re-evaluation for necessary changes. All changed records were retrospectively reviewed and classified as either lesions that were found in initial-time-point images but were changed into negative by adding delayed scan or newly detected findings of suspected malignancy on delayed-time-point images; lesions suspected to be malignant were subjected to further pathologic review. Diagnostic performance according to sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were calculated and compared between initial-time-point and dual-time-point imaging.Fifty-four records were changed after addition of the delayed-time-point imaging. Of the 105 suspected malignancies on initial-time-point images, 10 were changed into negative following the delayed scan. In addition, 44 lesions were newly detected as suspected malignancies on delayed-time-point images. Thirty-six lesions were proven to be pathologically malignant. Of these, 26 were detected on initial-time-point images, and 8 lesions (gastrointestinal adenocarcinoma, 6; prostate adenocarcinoma, 2) were observed on delayed-time-point images. The sensitivity of dual-time-point imaging (58.6% [34/58]) was significantly higher than that of initial-time-point imaging only (44.8% [26/58]) (P = .005); however, specificity and accuracy of dual-time-point imaging (96.6% [2968/3073] and 95.9% [3002/3131], respectively) were significantly lower than those of initial-time-point imaging only (97.4% [2994/3073] and 96.5% [3020/3131], respectively) (P < .0001 and P = .013, respectively). There were no significant differences in PPV (initial-time-point imaging: 24.8% [26/105], dual-time-point imaging: 24.5% [34/139]) and NPV (98.9% [2994/3026] and 99.2% [2968/3073], respectively).The inclusion of delayed PET/CT in screening examinations facilitated the detection of pathologically malignant lesions, particularly in the gastrointestinal tract, while also detecting benign and false-negative lesions.

Is it time to abandon the digital rectal examination? Lessons from the PLCO Cancer Screening Trial and peer-reviewed literature

OBJECTIVE

In 2012 the US Preventive Services Task Force released recommendations against prostate specific antigen (PSA) based screening for prostate cancer, but did not fully address screening via digital rectal exam (DRE). As such, many practitioners continue to perform DRE in attempts to identify men with clinically significant prostate cancer (CSPC). This study seeks to determine the value of DRE in detecting CSPC in the era of PSA-based screening.

METHODS

Data from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Screening Trial, a nationwide population-based study evaluating cancer screening programs and their impact on cancer mortality, was analyzed for PSA, DRE, and cancer status. In the screening arm of the PLCO, 38,340 men received annual PSA and DRE examinations for the first 3 years. Those with an abnormal test result were referred to their individual care provider for biopsy. The ability of DRE to detect CSPC, defined as intermediate risk or higher based on National Comprehensive Cancer Network guidelines and age ≤75, was evaluated in the context of both normal and abnormal PSA.

RESULTS

A total of 5064 men had abnormal DRE in the setting of normal PSA, of whom 99 (2%) were diagnosed with CSPC. When both PSA and DRE were abnormal, 218 (20%) participants were diagnosed with CSPC (RR = 2.06 [1.78-2.39] versus abnormal PSA alone).

CONCLUSIONS

DRE screening in the setting of normal PSA captured an additional 2% of men with CSPC. This incremental gain suggests that routine DRE screening subjects a large number of men to invasive, potentially uncomfortable examinations for relatively minimal gain. Key limitations: Our conclusions are based on data derived from the PLCO study which has been criticized on the basis of inconsistent biopsies following positive screening tests, lack of end of study biopsies to determine population disease burden, and low numbers of black men.

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.

Age-Adjusted PSA Levels in Prostate Cancer Prediction: Updated Results of the Tyrol Prostate Cancer Early Detection Program

Objective

To reduce the number of unnecessary biopsies in patients with benign prostatic disease, however, without missing significant PCa the present study re-evaluates the age-dependent PSA cut-offs in the Tyrol Prostate Cancer (PCa) early detection program.

Patients and Methods

The study population included 2225 patients who underwent prostate biopsy due to elevated PSA levels at our department. We divided our patient collective into four age groups: ≤49 years (n = 178), 50-59 years (n = 597), 60-69 years (n = 962) and ≥70 years (n = 488). We simulated different scenarios for PSA cut-off values between 1.25 and 6 ng/mL and fPSA% between 15 and 21% for all four age groups and calculated sensitivity, specificity, confidence intervals and predictive values.

Results

PCa was detected in 1218 men (54.7%). We found that in combination with free PSA ≤21% the following PSA cut-offs had the best cancer specificity: 1.75 ng/ml for men ≤49 years and 50-59 years, 2.25 ng/ml for men aged 60-69 years and 3.25 ng/ml for men ≥70 years. Using these adjusted PSA cut-off values all significant tumors are recognized in all age groups, yet the number of biopsies is reduced. Overall, one biopsy is avoided in 13 to 14 men (number needed to screen = 13.3, reduction of biopsies = 7.5%) when decision regarding biopsy is done according to the “new” cut-off values instead of the “old” ones. For the different age groups the number needed to screen to avoid one biopsy varied between 9.2 (≤49 years) and 17.4 (50-59 years).

Conclusion

With “new”, fine-tuned PSA cut-offs we detect all relevant PCa with a significant reduction of biopsies compared to the “old” cut-off values. Optimization of age-specific PSA cut-offs is one step towards a smarter strategy in the Tyrol PCa Early Detection Program.

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

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

The costs of identifying undiagnosed prostate cancer in asymptomatic men in New Zealand general practice

BACKGROUND

Screening for prostate cancer (PCa) using the prostate-specific antigen (PSA) test is widespread in New Zealand. Aim. This study estimates the costs of identifying a new case of PCa by screening asymptomatic men.

METHODS

Men aged 40+, who had PSA tests in 31 general practices in the Midland Cancer Network region during 2010, were identified. Asymptomatic men without a history of PCa were eligible for this study. A decision tree was constructed to estimate the screening costs. We assumed GPs spent 3 minutes of the initial consultation on informed consent of PCa screening.

RESULTS

About 70.7% of the estimated costs were incurred in general practice. The screening costs per cancer detected were NZ$10 777 (€5820; £4817). The estimated costs for men aged 60-69 were NZ$6268 compared to NZ$24 290 for men aged 40-49, NZ$30 022 for 50-59 and NZ$10 957 for those aged 70+. The costs for Māori were NZ$7685 compared to NZ$11 272 for non-Māori. The costs for men without PSA testing history in 2007-09 were NZ$8887 compared to NZ$13 870 if the men had PSA tests in 2007-09. If we assumed a PSA test involved a full 15-minute general practice consultation, the estimated costs increased to NZ$26 877 per PCa identified.

CONCLUSIONS

Screening of asymptomatic men for PCa is widely practiced. Most of the costs of screening were incurred in general practice. Calls for men to receive increased information on the harms and benefits of screening will substantially increase the costs. The current costs could be reduced by better targeting of screening.

ACR Appropriateness Criteria prostate cancer--pretreatment detection, staging, and surveillance

Prostate cancer is the most common noncutaneous male malignancy in the United States. The use of serum prostate-specific antigen as a screening tool is complicated by a significant fraction of nonlethal cancers diagnosed by biopsy. Ultrasound is used predominately as a biopsy guidance tool. Combined rectal examination, prostate-specific antigen testing, and histology from ultrasound-guided biopsy provide risk stratification for locally advanced and metastatic disease. Imaging in low-risk patients is unlikely to guide management for patients electing up-front treatment. MRI, CT, and bone scans are appropriate in intermediate-risk to high-risk patients to better assess the extent of disease, guide therapy decisions, and predict outcomes. MRI (particularly with an endorectal coil and multiparametric functional imaging) provides the best imaging for cancer detection and staging. There may be a role for prostate MRI in the context of active surveillance for low-risk patients and in cancer detection for undiagnosed clinically suspected cancer after negative biopsy results. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Synthesis and in vitro evaluation of MR molecular imaging probes using J591 mAb-conjugated SPIONs for specific detection of prostate cancer

Carcinoma of the prostate is the most frequent diagnosed malignant tumor in men and is the second leading cause of cancer-related death in this group. The cure rate of prostate cancer is highly dependent on the stage of disease at the diagnosis and early detection is key to designing effective treatment strategies. The objective of the present study is to make a specific MR imaging probe for targeted imaging of cancer cells. We take advantage of the fact that many types of prostate cancer cells express high levels of prostate-specific membrane antigen (PSMA) on their cell surface. The imaging strategy is to use superparamagnetic iron oxide nanoparticles (SPIONs), attached to an antibody (J591) that binds to the extracellular domain of PSMA, to specifically enhance the contrast of PSMA-expressing prostate cancer cells. Conjugation of mAb J591 to commercial SPIONs was achieved using a heterobifunctional linker, sulfo-SMCC. Two types of prostate cancer cell lines were chosen for experiments: LNCaP (PSMA+) and DU145 (PSMA-). MRI and cell uptake experiments demonstrated the high potential of the synthesized nanoprobe as a specific MRI contrast agent for detection of PSMA-expressing prostate cancer cells.

Screening for prostate cancer

BACKGROUND

Any form of screening aims to reduce disease-specific and overall mortality, and to improve a person's future quality of life. Screening for prostate cancer has generated considerable debate within the medical and broader community, as demonstrated by the varying recommendations made by medical organizations and governed by national policies. To better inform individual patient decision-making and health policy decisions, we need to consider the entire body of data from randomised controlled trials (RCTs) on prostate cancer screening summarised in a systematic review. In 2006, our Cochrane review identified insufficient evidence to either support or refute the use of routine mass, selective, or opportunistic screening for prostate cancer. An update of the review in 2010 included three additional trials. Meta-analysis of the five studies included in the 2010 review concluded that screening did not significantly reduce prostate cancer-specific mortality. In the past two years, several updates to studies included in the 2010 review have been published thereby providing the rationale for this update of the 2010 systematic review.

OBJECTIVES

To determine whether screening for prostate cancer reduces prostate cancer-specific mortality or all-cause mortality and to assess its impact on quality of life and adverse events.

SEARCH METHODS

An updated search of electronic databases (PROSTATE register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CANCERLIT, and the NHS EED) was performed, in addition to handsearching of specific journals and bibliographies, in an effort to identify both published and unpublished trials.

SELECTION CRITERIA

All RCTs of screening versus no screening for prostate cancer were eligible for inclusion in this review.

DATA COLLECTION AND ANALYSIS

The original search (2006) identified 99 potentially relevant articles that were selected for full-text review. From these citations, two RCTs were identified as meeting the inclusion criteria. The search for the 2010 version of the review identified a further 106 potentially relevant articles, from which three new RCTs were included in the review. A total of 31 articles were retrieved for full-text examination based on the updated search in 2012. Updated data on three studies were included in this review. Data from the trials were independently extracted by two authors.

MAIN RESULTS

Five RCTs with a total of 341,342 participants were included in this review. All involved prostate-specific antigen (PSA) testing, with or without digital rectal examination (DRE), though the interval and threshold for further evaluation varied across trials. The age of participants ranged from 45 to 80 years and duration of follow-up from 7 to 20 years. Our meta-analysis of the five included studies indicated no statistically significant difference in prostate cancer-specific mortality between men randomised to the screening and control groups (risk ratio (RR) 1.00, 95% confidence interval (CI) 0.86 to 1.17). The methodological quality of three of the studies was assessed as posing a high risk of bias. The European Randomized Study of Screening for Prostate Cancer (ERSPC) and the US Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial were assessed as posing a low risk of bias, but provided contradicting results. The ERSPC study reported a significant reduction in prostate cancer-specific mortality (RR 0.84, 95% CI 0.73 to 0.95), whilst the PLCO study concluded no significant benefit (RR 1.15, 95% CI 0.86 to 1.54). The ERSPC was the only study of the five included in this review that reported a significant reduction in prostate cancer-specific mortality, in a pre-specified subgroup of men aged 55 to 69 years of age. Sensitivity analysis for overall risk of bias indicated no significant difference in prostate cancer-specific mortality when referring to the meta analysis of only the ERSPC and PLCO trial data (RR 0.96, 95% CI 0.70 to 1.30). Subgroup analyses indicated that prostate cancer-specific mortality was not affected by the age at which participants were screened. Meta-analysis of four studies investigating all-cause mortality did not determine any significant differences between men randomised to screening or control (RR 1.00, 95% CI 0.96 to 1.03). A diagnosis of prostate cancer was significantly greater in men randomised to screening compared to those randomised to control (RR 1.30, 95% CI 1.02 to 1.65). Localised prostate cancer was more commonly diagnosed in men randomised to screening (RR 1.79, 95% CI 1.19 to 2.70), whilst the proportion of men diagnosed with advanced prostate cancer was significantly lower in the screening group compared to the men serving as controls (RR 0.80, 95% CI 0.73 to 0.87). Screening resulted in a range of harms that can be considered minor to major in severity and duration. Common minor harms from screening include bleeding, bruising and short-term anxiety. Common major harms include overdiagnosis and overtreatment, including infection, blood loss requiring transfusion, pneumonia, erectile dysfunction, and incontinence. Harms of screening included false-positive results for the PSA test and overdiagnosis (up to 50% in the ERSPC study). Adverse events associated with transrectal ultrasound (TRUS)-guided biopsies included infection, bleeding and pain. No deaths were attributed to any biopsy procedure. None of the studies provided detailed assessment of the effect of screening on quality of life or provided a comprehensive assessment of resource utilization associated with screening (although preliminary analyses were reported).

AUTHORS' CONCLUSIONS

Prostate cancer screening did not significantly decrease prostate cancer-specific mortality in a combined meta-analysis of five RCTs. Only one study (ERSPC) reported a 21% significant reduction of prostate cancer-specific mortality in a pre-specified subgroup of men aged 55 to 69 years. Pooled data currently demonstrates no significant reduction in prostate cancer-specific and overall mortality. Harms associated with PSA-based screening and subsequent diagnostic evaluations are frequent, and moderate in severity. Overdiagnosis and overtreatment are common and are associated with treatment-related harms. Men should be informed of this and the demonstrated adverse effects when they are deciding whether or not to undertake screening for prostate cancer. Any reduction in prostate cancer-specific mortality may take up to 10 years to accrue; therefore, men who have a life expectancy less than 10 to 15 years should be informed that screening for prostate cancer is unlikely to be beneficial. No studies examined the independent role of screening by DRE.

GAD1 is a biomarker for benign and malignant prostatic tissue

OBJECTIVE

Tissue-specific markers are useful for identification of tumour type in advanced cancers of unknown origin. This study investigated the expression of glutamate decarboxylase 1 (GAD1) in prostate and control tissue compared with the established prostate-specific markers prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSMA).

MATERIAL AND METHODS

A tissue microarray was constructed of 36 prostate adenocarcinomas, eight benign prostate samples and benign and malignant control tissues from urinary bladder, lung and rectum. Immunohistochemistry for GAD1, PSA and PSMA was performed. The products of staining intensity and extent were analysed. The GAD1 antibody was validated by Western blot. Real-time polymerase chain reaction (RT-PCR) was performed on malignant and benign samples from each tissue type.

RESULTS

GAD1 and PSA immunostains were significantly stronger in malignant and benign prostatic tissue than in controls. PSMA was stronger in prostate cancer than in urothelial and rectal cancer but had a lower specificity than GAD1 and PSA. GAD1 expression decreased with increasing Gleason score. RT-PCR confirmed the presence of mRNA for GAD1, PSA and PSMA in prostate samples.

CONCLUSION

GAD1 is expressed in benign and malignant prostatic tissue and may serve as a highly prostate-specific tissue biomarker.

Prostate cancer incidence among American Indian and Alaska Native men, US, 1999-2004

BACKGROUND

American Indian and Alaska Native (AI/AN) men experience lower incidence of prostate cancer than other race/ethnic populations in the US, but racial misclassification of AI/AN men threatens the validity of these estimates. To the authors' knowledge, little is known concerning prostate-specific antigen (PSA) testing in AI/AN men.

METHODS

The authors linked cancer registry data with Indian Health Service enrollment records to improve race classification. Analyses comparing cancer incidence rates and stage at diagnosis for AI/AN and non-Hispanic white (NHW) men for 6 geographic regions focused on counties known to have less race misclassification. The authors also used Behavioral Risk Factors Surveillance System data to characterize PSA testing in AI/AN men.

RESULTS

Prostate cancer incidence rates were generally lower in AI/AN than in NHW men for all regions combined (rate ratio of 0.68). However, regional variation was noted among AI/AN men, with incidence rates (per 100,000 population) ranging from 65.7 in the Southwest to 174.5 on the Northern Plains. The rate of distant stage disease was somewhat higher among AI/AN (7.8) than NHW (6.2) men. Nationally, AI/AN men were less likely than NHW men to have undergone recent PSA testing (48.4% vs 58.0%), with prominent regional variation in screening rates noted.

CONCLUSIONS

Prostate cancer incidence rates and the proportion of men with recent PSA testing were lower for AI/AN men than for NHW men. However, incident rates and rate of distant stage varied by region more for AI/AN than for NHW. Further research is needed among AI/AN men to evaluate strategies for better understanding the causes of the regional variation in prostate cancer incidence.

Relevance of the prostate-specific antigen (PSA) nanotest compared to the classical PSA test in the organized mass screening of prostate cancer

OBJECTIVE

To assess the reliability of a new measurement of prostate-specific antigen (PSA) using a blotting-paper assay (nanotest) compared to the standard PSA immunoassay.

SUBJECTS AND METHODS

The PSA level was measured in 205 men volunteers (median age 70 years, range 41-75) using a nanotest and a standard PSA immunoassay, collected at the same time; 30 microL of capillary blood placed on to a blotting paper were collected for the nanotest and sent by mail to the same laboratory for the two assays. The results were compared statistically using the Spearman test, the intraclass correlation coefficient and the Bland-Altman test.

RESULTS

The nanotest threshold for an abnormal PSA level was 78 pg/mL, which corresponded to a standard PSA value of 3 ng/mL, with a sensitivity of 100%. There was a significant correlation (r = 0.98, Spearman test; P < 0.001) between the nanotest and the standard PSA assay. The intraclass correlation coefficient was 0.87. The Bland-Altman test showed a good agreement between the nanotest and the standard PSA assay, but there was an increasing proportional difference with increasing PSA value.

CONCLUSION

There was a very high correlation between the nanotest and the standard PSA assay, especially for standard PSA levels of <5 ng/mL. Economic and clinical studies are indicated to confirm the utility of the nanotest in organized mass screening of prostate cancer.

Is digital rectal examination still necessary in the early detection of prostate cancer?

BACKGROUND

PSA measurement is important in prostate cancer detection. However, applying cut-off values of >4 ng/ml as indication for biopsy misses 20-30% of tumours.

AIMS

To determine the number of patients with prostate cancer and normal age-related PSA, referred for TRUS biopsy due to abnormal DRE alone.

METHODS

We reviewed patients referred for biopsy over 12 months. Indication for biopsy included abnormal PSA, abnormal DRE, or both.

RESULTS

Four-hundred and sixty-five (465) TRUS biopsies were performed, 209 were positive. Of the 183 (183/209) positive on whom complete data were available, 4 (2.2%) had a normal age-related PSA but an abnormal DRE.

CONCLUSIONS

Metastatic prostate cancer remains incurable. Therefore detection of organ-confined and potentially curable disease, is crucial. Though PSA has led to earlier detection, this study emphasises the importance of clinical examination, illustrating a normal PSA cannot eliminate the possibility of cancer. DRE and PSA should be interpreted as being collaborative, not competitive.

An abnormal digital rectal examination is an independent predictor of Gleason > or =7 prostate cancer in men undergoing initial prostate biopsy: a prospective study of 790 men

OBJECTIVE

To evaluate our experience with a referral population of 790 patients undergoing initial prostate biopsy in the prostate-specific antigen (PSA) era, to assess the role of a digital rectal examination (DRE) in predicting the outcome of prostate needle biopsy (PNB) and to evaluate if DRE findings were associated with cancer grade.

PATIENTS AND METHODS

We analysed 790 consecutive men who had an initial PNB from September 1999 to July 2005 by one urologist (C.P.). All data were collected in a prospective database. Multivariate logistic regression analysis was used to determine the relationship between an abnormal DRE and the presence of cancer and cancer grade on PNB.

RESULTS

An abnormal DRE was an independent predictor for prostate cancer on multivariate analysis (odds ratio 2.18, 95% confidence interval 1.53-3.10, P < 0.001). In all patients biopsied, an abnormal DRE was associated with a Gleason sum of > or = 7 on multivariate analysis (odds ratio 3.39, 2.07-5.53, P = 0.001).

CONCLUSION

A DRE is a useful and important tool to use when assessing patients for a PNB. An abnormal DRE independently predicted high-grade disease in these men. These results might have important implications in the prediction of men with other than indolent prostate cancer.

Screening for prostate cancer

BACKGROUND

Any form of screening aims to reduce mortality and increase a person's quality of life. Screening for prostate cancer has generated considerable debate within the medical community, as demonstrated by the varying recommendations made by medical organizations and governed by national policies. Much of this debate is due to the limited availability of high quality research and the influence of false-positive or false-negative results generated by use of the diagnostic techniques such as the digital rectal examination (DRE) and prostate specific antigen (PSA) blood test.

OBJECTIVES

To determine whether screening for prostate cancer reduces prostate cancer mortality and has an impact on quality of life.

SEARCH STRATEGY

Electronic databases (PROSTATE register, CENTRAL the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, CANCERLIT and the NHS EED) were searched electronically in addition to hand searching of specific journals and bibliographies in an effort to identify both published and unpublished trials.

SELECTION CRITERIA

All randomised controlled trials of screening versus no screening or routine care for prostate cancer were eligible for inclusion in this review.

DATA COLLECTION AND ANALYSIS

The search identified 99 potentially relevant articles that were selected for full text review. From these 99 citations, two randomised controlled trials were identified as meeting the review's inclusion criteria. Data from the trials were independently extracted by two authors.

MAIN RESULTS

Two randomised controlled trials with a total of 55,512 participants were included; however, both trials had methodological weaknesses. Re-analysis using intention-to-screen and meta-analysis of results from the two randomised controlled trials indicated no statistically significant difference in prostate cancer mortality between men randomised for prostate cancer screening and controls (RR 1.01, 95% CI: 0.80-1.29). Neither study assessed the effect of prostate cancer screening on quality of life, all-cause mortality or cost effectiveness.

AUTHORS' CONCLUSIONS

Given that only two randomised controlled trials were included, and the high risk of bias of both trials, there is insufficient evidence to either support or refute the routine use of mass, selective or opportunistic screening compared to no screening for reducing prostate cancer mortality. Currently, no robust evidence from randomised controlled trials is available regarding the impact of screening on quality of life, harms of screening, or its economic value. Results from two ongoing large scale multicentre randomised controlled trials that will be available in the next several years are required to make evidence-based decisions regarding prostate cancer screening.

Role of transperineal six-core prostate biopsy in patients with prostate-specific antigen level greater than 10 ng/mL and abnormal digital rectal examination findings

OBJECTIVES

To define whether six-core biopsies still have a role in patients presenting with prostate-specific antigen (PSA) levels greater than 10 ng/mL and abnormal digital rectal examination (DRE) findings. Recent studies have suggested that the six-core biopsy is inadequate for the diagnosis of prostate cancer; however, it remains controversial whether an increased number of cores is justified in all patients.

METHODS

From June 2002 to February 2005, 122 (18.8%) of 650 patients underwent prostate biopsy because of a PSA level greater than 10 ng/mL and abnormal DRE findings. All patients underwent transperineal ultrasound-guided prostate biopsy in a standardized fashion: a six-core biopsy was performed first, followed by six additional cores during the same session, four in the peripheral and two in the transition zone.

RESULTS

The detection rate in patients with a PSA level greater than 10 ng/mL and abnormal DRE findings was 72.1% (88 of 122) and 75.4% (92 of 122) using the 6-core and 12-core biopsy, respectively. One case of tumor was missed by the six-core biopsy among patients with a PSA level greater than 15 ng/mL and abnormal DRE findings. No cases of tumor were missed by six-core biopsy in the group with a PSA level greater than 20 ng/mL and abnormal DRE findings.

CONCLUSIONS

Six-core biopsy provided a similar cancer detection rate compared with 12-core biopsy in patients with PSA levels greater than 10 ng/mL and abnormal DRE findings. An initial approach with 6-core biopsy is reasonable in patients with a PSA level greater than 10 ng/mL and abnormal DRE findings and is advocated in those with PSA greater than 20 ng/mL and abnormal DRE findings.

Relationship Among Initial Serum Prostate Specific Antigen, Prostate Specific Antigen Progression and Prostate Cancer Detection at Repeat Screening Visits

PURPOSE

We evaluated the probability of positive serum PSA (3 ng/ml or greater) and CaP detection at annual followup visits in men with negative initial PSA (less than 3 ng/ml) to optimize the re-screening schedule.

MATERIALS AND METHODS

Data on 5,387 men 45 to 80 years old with negative PSA and no CaP diagnosis at the first screening visit were obtained from the Laval University Prostate Cancer Screening Program database. Accelerated failure time regressions were fitted to time from baseline to positive PSA and to time from positive PSA to CaP detection. The models were combined to estimate the cumulative probability of positive PSA followed by CaP detection at re-screening.

RESULTS

The 5-year cumulative probability of detecting CaP at annual visits in men with baseline PSA up to 1.5 ng/ml remained below 0.8%, while it was 1.3%, 4.8% and 8.3% in men with PSA 1.5 to less than 2, 2 to less than 2.5 and 2.5 to less than 3 ng/ml, respectively. Time to positive PSA significantly decreased with increasing baseline PSA and age, while the time between positive PSA and CaP detection depended only on age. Men with PSA below 1.0 ng/ml could wait for 4 to 5 years before being re-tested, while men with PSA between 1.0 and 1.5 ng/ml should be screened every second year and men with PSA 1.5 ng/ml or greater should be screened every year.

CONCLUSIONS

The proposed retesting schedule using current PSA and age decreases the number of visits by 38.1%, while delaying the detection of only 2.4% of CaPs that would have been detected using annual PSA testing.

Regulator of G-protein signaling 2 (RGS2) inhibits androgen-independent activation of androgen receptor in prostate cancer cells

Hormones acting through G protein-coupled receptors (GPCRs) can cause androgen-independent activation of androgen receptor (AR) in prostate cancer cells. Regulators of G-protein signaling (RGS) proteins, through their GTPase activating protein (GAP) activities, inhibit GPCR-mediated signaling by inactivating G proteins. Here, we identified RGS2 as a gene specifically downregulated in androgen-independent prostate cancer cells. Expression of RGS2, but not other RGS proteins, abolished androgen-independent AR activity in androgen-independent LNCaP cells and CWR22Rv1 cells. In LNCaP cells, RGS2 inhibited G(q)-coupled GPCR signaling. Expression of exogenous wild-type RGS2, but not its GAP-deficient mutant, significantly reduced AR activation by constitutively activated G(q)Q209L mutant whereas silencing endogenous RGS2 by siRNA enhanced G(q)Q209L-stimulated AR activity. RGS2 had no effect on RGS-insensitive G(q)Q209L/G188S-induced AR activation. Furthermore, extracellular signal-regulated kinase 1/2 (ERK1/2) was found to be involved in RGS2-mediated regulation of androgen-independent AR activity. In addition, RGS2 functioned as a growth suppressor for androgen-independent LNCaP cells whereas androgen-sensitive LNCaP cells with RGS2 silencing had a growth advantage under steroid-reduced conditions. Finally, RGS2 expression level was significantly decreased in human prostate tumor specimens. Taken together, our results suggest RGS2 as a novel regulator of AR signaling and its repression may be an important step during prostate tumorigenesis and progression.

Current status of endocrine therapy in localized prostate cancer: cure has become a strong possibility

It is clear that all available means should be taken to diagnose prostate cancer early and to use efficient therapy immediately in order to prevent prostate cancer from migrating to the bones where treatment becomes extremely difficult and cure or even long-term control of the disease is an exception. The only means of preventing prostate cancer from migrating to the bones and becoming incurable is efficient treatment at the localized stage of the disease. In fact, since radical prostatectomy, radiotherapy and brachytherapy can achieve cure in about 50% of cases, these approaches are all equally valid choices as first treatment of localized prostate cancer. However, in view of the current knowledge and available data, nowadays, androgen blockade should also be considered as first line treatment. While showing the high efficacy of hormonal therapy in localized prostate cancer, present knowledge clearly indicate that long-term treatment with the best available hormonal drugs, somewhat similar to the 5 years of Tamoxifen in breast cancer, is required for optimal control of prostate cancer. It is also clear from the data analyzed that combined androgen blockage alone could well be an efficient therapy of localized prostate cancer while it has already been recognized as the best therapy for metastatic disease. This paper presents and discusses the current knowledge available on the use and results of endocrine therapy in localized prostate cancer.

Value of various PSA parameters for diagnosing prostate cancer in men with normal digital rectal examination

OBJECTIVES

The risks of identifying prostate cancer (PCa) in patients with serum total PSA (tPSA) between 4 and 10 ng/dl are between 25 and 35%. There are no data in Brazil showing the incidence of disease when all variables for PSA assessment are considered altogether, specifically tPSA, free fraction, PSA velocity and PSA stratified by age. The objective in this work was to define the incidence of disease in a population of men with abnormal values of PSA variables and normal digital rectal examination.

MATERIALS AND METHODS

Between 1998 and 2003, 273 prostate biopsies were performed by the same radiologist and analyzed by the same pathologist. All patients had a normal digital rectal examination and biopsy had been indicated due to tPSA above 4 ng/dl or free-to-total PSA ratio (F/T PSA) below 15% or PSA velocity higher than 25% per year or a PSA level regarded as high for the age range. The relationship between these parameters and the positivity for prostate caner was determined.

RESULTS

Patients' mean age was 63.8 years, and PCa was identified in 135 cases (49.5%). The incidence of PCa, related to unitary variations in tPSA, ranged from the limits of 33 to 80%, respectively, in tPSA < 3 and PSA between 15.1 to 20. When the other PSA parameters were assessed (free PSA, PSA according to age, rise velocity) PCa was detected in more than 25.3% of cases.

CONCLUSION

When patients with normal digital rectal examination are selected for prostate biopsy due to tPSA levels above 4 or F/T PSA ratio lower than 15% or PSA velocity higher than 25% per year or high PSA for the age range, the incidence of PCa is quite higher than that observed in a population selected exclusively with basis on total PSA value.

Major impact of hormonal therapy in localized prostate cancer--death can already be an exception

For about 50 years, androgen blockade in prostate cancer has been limited to monotherapy (surgical castration) or high doses of estrogens in patients with advanced disease and bone metastases. The discovery of medical castration with LHRH agonists has led to fundamental changes in the endocrine therapy of prostate cancer. In 1979, the first prostate cancer patient treated with an LHRH agonist received such treatment at the Laval University Medical Center. A long series of studies have clearly demonstrated that medical castration with an LHRH agonist has inhibitory effects on prostate cancer equivalent to those of surgical castration. The much higher acceptability of LHRH agonists has been essential to permit a series of studies in localized disease. Based upon the finding that the testicles and adrenals contribute approximately equal amounts of androgens in the human prostate, the combination of medical (LHRH agonist) or surgical castration associated with a pure antiandrogen (flutamide, nilutamide or bicalutamide) has led to the first demonstration of a prolongation of life in prostate cancer, namely a 10-20% decreased risk of death according to the various metaanalyses of all the studies performed in advanced disease. In analogy with the other types of advanced cancers, the success of combined androgen blockade in metastatic disease is limited by the development of resistance to treatment. To avoid the problem of resistance to treatment while taking advantage of the relative ease of diagnosis of prostate cancer at an "early" stage, the much higher acceptability of LHRH agonists has permitted a series of studies which have demonstrated a major reduction in deaths from prostate cancer ranging from 31% to 87% at 5 years of follow-up in patients with localized or locally advanced prostate cancer. Most importantly, recent data show that the addition of a pure antiandrogen to an LHRH agonist in order to block the androgens made locally in the prostate leads to a 90% long-term control or probable cure of prostate cancer.

Prostate-specific antigen velocity at low prostate-specific antigen levels as screening tool for prostate cancer: results of second screening round of ERSPC (ROTTERDAM)

OBJECTIVES

To study retrospectively whether the prostate-specific antigen (PSA) velocity, that is, the change in PSA level over time, might serve as a screening tool in this PSA range. It is estimated that 40% of detectable prostate cancers are present in men with a PSA level of 4.0 ng/mL or less. Digital rectal examination and/or transrectal ultrasonography have been used as screening tools at these low PSA levels, but this approach is not very efficient.

METHODS

The possible predictors (including PSA velocity) for biopsy outcome were studied using univariate and multivariate logistic regression analysis in 774 men who underwent biopsy between November 1997 and January 2002 in the second screening round of the European Randomised Study of Screening for Prostate Cancer (ERSPC). The clinical stage of the tumors was determined, and the Gleason scores of the biopsies were studied.

RESULTS

A total of 149 cancers were found (positive predictive value 19.2%). The odds ratio for the PSA velocity determined by univariate logistic regression analysis was 2.2 (95% confidence interval 0.7 to 6.9, P = 0.19) and was 0.73 (95% confidence interval 0.20 to 2.6, P = 0.64) by multivariate analysis. The distribution of the clinical stage of the detected tumors was 64.4% T1c, 32.2% T2, and 3.4% T3. The biopsy Gleason score was 6 in 84.5%, 7 in 14.2%, and 8 in 1.3%.

CONCLUSIONS

The number of cancers detected in this study and the distribution of clinical stage and biopsy Gleason score confirmed that a relatively large proportion of potentially curable cancers can be found in the low PSA ranges. The PSA velocity did not appear to be a useful screening tool for the identification of these cancers.

Screening decreases prostate cancer mortality: 11-year follow-up of the 1988 Quebec prospective randomized controlled trial

PURPOSE

This clinical trial is aimed at evaluating the impact of prostate cancer screening on cancer-specific mortality.

SUBJECTS AND METHODS

Forty-six thousand four hundred and eighty-six (46,486) men aged 45-80 years registered in the electoral roll of the Quebec city area were randomized in 1988 between screening and no screening. Screening included measurement of serum prostatic specific antigen (PSA) using 3.0 ng/ml as upper limit of normal and digital rectal examination (DRE) at first visit. At follow-up visits, serum PSA only was used.

RESULTS

Seventy-four (74) deaths from prostate cancer occurred in the 14,231 unscreened controls while 10 deaths were observed in the screened group of 7,348 men during the first 11 years following randomization. Median follow-up of screened men was 7.93 years. A Cox proportional hazards model of the age at death from prostate cancer shows a 62% reduction (P < 0.002, Fisher's exact test) of cause-specific mortality in the screened men (P = 0.005). These results are in agreement with the continuous decrease of prostate cancer mortality observed in North America.

MISCAN: estimating lead-time and over-detection by simulation

OBJECTIVE

To estimate the mean lead-time and rate of over-detection associated with screening for prostate cancer with prostate-specific antigen.

METHODS

Simulation models, fitted to the results of the Rotterdam section of the European Randomized Study of Screening for Prostate Cancer, were used to predict the mean lead-time and over-detection rate in population-based screening programmes.

RESULTS

The mean lead-time is estimated to be 11-12 years and over-detection to occur in half the cases found by population screening. The estimates are compared with published estimates.

CONCLUSIONS

The effect of lead-time and over-detection on the balance of positive and negative consequences of screening cannot be neglected.

Prostate-specific antigen and screening for prostate cancer

This article discusses prostate-specific antigen (PSA) and screening for prostate cancer. Topics explored include the history of PSA testing, the biology of PSA, clinical uses of PSA testing, improving the accuracy of PSA testing, and controversies in prostate cancer screening.

Elevated levels of prostate-specific antigen (PSA) in prostate cancer cells expressing mutant p53 is associated with tumor metastasis

The underlying basis for rising levels of prostate-specific antigen (PSA) in prostate cancer is not fully understood, but attention has turned to the possibility that loss of normal p53 function might be directly involved. We have investigated the relationship between p53 function and PSA expression using in vitro and in vivo approaches. Three prostate cancer-derived p53 mutants (F134L, M237L, R273H) were introduced into LNCaP prostate cancer cells and stable transfectants established. Expression of mutant p53 was demonstrated by Western blot analysis, inactivation of wtp53 function, and a loss of p53-dependent responses to DNA damage induced by UV-irradiation and cisplatin. Levels of PSA mRNA and secreted protein were determined by RT-PCR and Western blotting, respectively. Serine protease activity was assessed using an esterase assay. In vivo effects of mutant p53 expression were examined after orthotopic implantation into prostates of nude mice. Expression of all p53 mutants was associated with elevated PSA mRNA and secreted PSA protein. In a representative line, mutant p53 was also associated with increased PSA protease-like activity compared with a control line expressing wildtype p53. Overall PSA levels, and PSA levels in serum from mice bearing tumors derived from cells expressing mutant p53, were increased compared with levels in mice bearing tumors derived from control cells. In addition, the tumors derived from cells with mutant p53 had increased vascularization and induced lymph node metastases. These data provide in vitro and in vivo support for the notion that p53 mutations directly contribute to increased levels of serum PSA, and are associated with more aggressive tumors.

Early detection of prostate cancer with low PSA cut-off values leads to significant stage migration in radical prostatectomy specimens

BACKGROUND

The introduction of prostate-specific antigen (PSA) contributed to a shift in tumor stage at diagnosis in patients with prostate cancer. The aim of the present study was to evaluate the effects of PSA screening with low PSA cut-off values on mean total and percent-free PSA levels in patients with prostate cancers at the time of diagnosis as well as on pathologic stage and mean Gleason scores in positive biopsies and radical prostatectomy specimens.

METHODS

Data of 875 patients who were diagnosed with prostate cancers between 1996 and 2001 were analyzed. Patients were stratified into six groups according to the year of biopsy. Annual changes in total and percent-free PSA values, in Gleason scores of biopsies and radical prostatectomy specimens, and in pathologic stages of radical prostatectomy specimens were assessed.

RESULTS

Mean PSA of patients diagnosed with prostate cancer decreased from 13.11 ng/ml (percent-free PSA: 11.89%) in 1996 to 7.33 ng/ml (percent-free PSA: 12.58%) in 2001 (P < 0.05). The percentage of organ-confined prostatectomy specimens increased from 64.3% in 1996 to 81.5% in 2001 (P < 0.05). However, mean Gleason scores increased from 5.23 to 6.33 over the 6 years (P < 0.05). The percentage of patients with biopsy-proven prostate cancers and PSA values below 4 ng/ml increased from 14.0% in 1996 to 39.2% in 2001. In the group with PSA values below 4 ng/ml organ-confined cancers were found in 80.0-95.2% of patients.

CONCLUSIONS

PSAg screening with low cut-off levels has led to a significant reduction of mean baseline PSA levels in prostate cancer patients and to a significant increase in the percentage of organ-confined radical prostatectomy specimens, whereas mean Gleason scores have remained relatively constant.

Lead times and overdetection due to prostate-specific antigen screening: estimates from the European Randomized Study of Screening for Prostate Cancer

BACKGROUND

Screening for prostate cancer advances the time of diagnosis (lead time) and detects cancers that would not have been diagnosed in the absence of screening (overdetection). Both consequences have considerable impact on the net benefits of screening.

METHODS

We developed simulation models based on results of the Rotterdam section of the European Randomized Study of Screening for Prostate Cancer (ERSPC), which enrolled 42,376 men and in which 1498 cases of prostate cancer were identified, and on baseline prostate cancer incidence and stage distribution data. The models were used to predict mean lead times, overdetection rates, and ranges (corresponding to approximate 95% confidence intervals) associated with different screening programs.

RESULTS

Mean lead times and rates of overdetection depended on a man's age at screening. For a single screening test at age 55, the estimated mean lead time was 12.3 years (range = 11.6-14.1 years) and the overdetection rate was 27% (range = 24%-37%); at age 75, the estimates were 6.0 years (range = 5.8-6.3 years) and 56% (range = 53%-61%), respectively. For a screening program with a 4-year screening interval from age 55 to 67, the estimated mean lead time was 11.2 years (range = 10.8-12.1 years), and the overdetection rate was 48% (range = 44%-55%). This screening program raised the lifetime risk of a prostate cancer diagnosis from 6.4% to 10.6%, a relative increase of 65% (range = 56%-87%). In annual screening from age 55 to 67, the estimated overdetection rate was 50% (range = 46%-57%) and the lifetime prostate cancer risk was increased by 80% (range = 69%-116%). Extending annual or quadrennial screening to the age of 75 would result in at least two cases of overdetection for every clinically relevant cancer detected.

CONCLUSIONS

These model-based lead-time estimates support a prostate cancer screening interval of more than 1 year.

Androgen blockade in prostate cancer in 2002: major benefits on survival in localized disease

The last 20 years have witnessed major advances in the field of prostate cancer, both in terms of diagnosis and treatment. Using screening with PSA, 99% of prostate cancers can now be diagnosed at a clinically localized or potentially curable stage. Over a 11-year period starting in 1988, the Québec screening study performed among 45,000 men aged 45-80 years has shown that the prostate cancer death incidence has decreased by 64% in men who had screening. The impact of screening, however, requires early application of the most efficacious treatments. In this context, the most important recent therapeutic advance in the field of prostate cancer is androgen blockade, namely medical castration with LHRH agonists, the availability of pure antiandrogens and combined androgen blockade (CAB) using medical or surgical castration in association with a pure antiandrogen. In the six studies performed in localized or locally advanced disease, the improved cancer-specific survival ranges between 37 and 81% at 5 years of follow-up for patients who received androgen blockade. On the other hand, data already available show that long term and continuous (not intermittent) androgen blockade is highly efficient and can achieve long term control or possible cure of localized prostate cancer.

Robustness of free prostate specific antigen measurements to reduce unnecessary biopsies in the 2.6 to 4.0 ng./ml. range

PURPOSE

Prostate specific antigen (PSA) cutoffs lower than 4.0 ng./ml. are being evaluated more frequently but lower PSA cutoffs increase the number of prostatic biopsies. PSA exists in several forms free and complexed to proteins. Percent free PSA is lower in men with prostate cancer. Accordingly, free PSA and complexed PSA have been used to distinguish between cancer and benign disease in the diagnostic gray zone of 4 to 10 ng./ml. to eliminate unnecessary biopsies. There are limited data on the robustness of free PSA measurements in the 2.6 to 4.0 ng./ml. total PSA range.

MATERIALS AND METHODS

We evaluated percent free PSA measurements to discriminate between cancer and benign conditions in 965 consecutive volunteers in a prostate cancer screening study who underwent prostatic biopsy for a PSA of 2.6 to 4.0 ng./ml. and had benign digital rectal examination.

RESULTS

Overall 25% of men had cancer detected. A 25% free PSA cutoff detected 85% of cancers and avoided 19% of negative (cancer-free) biopsies, while a 30% free PSA cutoff detected 93% of cancers and avoided only 9% of negative biopsies. Of those men who underwent radical prostatectomy 132 (80%) had pathologically organ confined tumors. Only 5% of these tumors fulfilled the published pathological criteria for possibly clinically unimportant tumors.

CONCLUSIONS

Percent free PSA provides risk assessment but does not eliminate many unnecessary prostatic biopsies while maintaining a high sensitivity in the narrow total PSA range of 2.6 to 4.0 ng./ml.

Prevention of cancer in the older person

Both primary and secondary cancer prevention may improve cancer control among older persons. Although chemoprevention of cancer is feasible, the agents currently used for chemoprevention have several complications. As a result, the use of these substances should be individualized based on risk-benefit ratio. It is reasonable to implement screening for cancer of the breast and of the large bowel in persons with a life expectancy of 5 years and longer. No definite recommendation may be issued at present related to screening for prostate, lung, and cervical cancer. Ongoing clinical trials may answer some of these questions.

Androgens induce expression of SPAK, a STE20/SPS1-related kinase, in LNCaP human prostate cancer cells

Genes that are regulated by androgens in the human prostate are believed to play an essential role in prostate physiology and they may also be involved in the proliferative response of prostate cancer cells to androgens. We used a cDNA subtraction approach to identify novel androgen-regulated transcripts in LNCaP cells that were exposed to 0.1 nM R1881 for 24 h. We report here that SPAK, a recently identified STE20/SPS1-related kinase that modulates p38 MAP kinase activity, exhibited increased expression in androgen-treated LNCaP cells. Androgen regulation of SPAK was both dose- and time-dependent. R1881-induced SPAK expression was completely abrogated by the antiandrogen casodex and by actinomycin D indicating that androgen induction of SPAK requires the androgen receptor and transcription. Cycloheximide caused a partial inhibition of R1881-induced SPAK expression which suggests that androgen induction of SPAK expression may require synthesis of additional proteins. Northern blot and ribonuclease protection assays demonstrated that SPAK is expressed at high levels in normal human testes and prostate, as well as in a number of breast and prostate cancer cell lines. These results identify SPAK, a member of a key cell signalling pathway, as an androgen-responsive gene in LNCaP cells. We hypothesize that SPAK may mediate androgen action in the normal and cancerous prostate gland.

Prostate pathology: histologic and molecular perspectives

The field of prostate cancer research is poised for dramatic improvements in our ability to better diagnose men at risk of prostate cancer and to better predict prognosis and response to treatment. Histopathologic and molecular analyses lie at the heart of these issues. Improvements in our understanding of the mechanisms of prostate carcinogenesis and in determining why the prostate seems to be so highly targeted for cancer development will lead to rational strategies of disease prevention.