The unintended burden of increased prostate cancer detection associated with prostate cancer screening and diagnosis

Factors influencing Nigerian men's decision to undergo prostate specific antigen testing

BACKGROUND

Prostate cancer is a major cause of cancer death in Nigerian men. Attempts to reduce mortality from prostate cancer have focused mainly on early detection of the disease by the use of PSA testing. As a result of the increased incidence of prostate cancer in Nigeria despite the widespread availability of testing facilities, it became pertinent to understand the salient factors that prompt Nigerian men to go for prostate cancer testing.

OBJECTIVE

This study explores the factors that influence a group of Nigerian men's decision to go for Prostate Specific Antigen (PSA) testing.

METHODS

Following ethical approval, semi structured interviews were conducted with a group of 10 men who had PSA test following consultation with their doctor with signs and symptoms at the University of Benin Teaching Hospital from July to August, 2010. Interview transcripts were analysed by employing steps proposed by Collaizi (1978).

RESULTS

Five themes were identified: the symptoms experienced, the influence of friends and relatives, older age associated with increased awareness, accessibility to testing services and the knowledge of the PSA test.

CONCLUSION

The study revealed that there continues to be a considerable lack of awareness and knowledge about prostate cancer and screening.

Long non-coding RNA ATB promotes growth and epithelial-mesenchymal transition and predicts poor prognosis in human prostate carcinoma

Long non-coding RNAs (lncRNAs) have been identified to be critical mediators in various tumors associated with cancer progression. Long non-coding RNA activated by TGF-β (lncRNA-ATB) is a stimulator of epithelial-mesenchymal transition (EMT) and serves as a novel prognostic biomarker for hepatocellular carcinoma. However, the biological role and clinical significance of lncRNA-ATB in human prostate cancer have yet to be fully elucidated. The present study was designed to explore the expression of lncRNA-ATB in human prostate cancer patients and the role of lncRNA-ATB in prostate cancer cells. We showed that lncRNA-ATB expression was significantly upregulated in tumor tissues in patients with prostate cancer in comparison with adjacent non-tumor tissues. Further analysis indicted that high lncRNA-ATB expression may be an independent prognostic factor for biochemical recurrence (BCR)-free survival in prostate cancer patients. Overexpression of lncRNA-ATB promoted, and knockdown of lncRNA-ATB inhibited the growth of prostate cancer cells via regulations of cell cycle regulatory protein expression levels. In addition, lncRNA-ATB stimulated epithelial-mesenchymal transition (EMT) associated with ZEB1 and ZNF217 expression levels via ERK and PI3K/AKT signaling pathways. These results indicated that lncRNA-ATB may be considered as a new predictor in the clinical prognosis of patients with prostate cancer. Overexpression of lncRNA-ATB exerts mitogenic and EMT effects of prostate cancer via activation of ERK and PI3K/AKT signaling pathways.

Treatment modalities for Māori and New Zealand European men with localised prostate cancer

OBJECTIVES

To examine diagnostic and treatment pathways for Māori (the indigenous people of New Zealand [NZ]) and NZ European men with prostate cancer in order to identify causes of higher mortality rates for Māori men.

METHODS

All Māori men (150) diagnosed with prostate cancer in the Midland Cancer Network region between 2007 and 2010 were identified from the NZ Cancer Registry and frequency age-matched with three randomly sampled NZ European men. Clinical records of these men were searched for information on clinical stage at diagnosis, comorbidities, and type of treatment for localised disease.

RESULTS

The final cohort included 136 Māori and 400 NZ European men, of whom 97 Māori and 311 NZ European were diagnosed with localised prostate cancer. Māori men were twice as likely to be diagnosed with distant metastases compared with NZ European men (19.1 vs 9.8 %). Māori men with localised disease were less likely to be treated with radical prostatectomy compared with NZ European men [RR 0.66 (95 % CI 0.48, 0.90)]. Multivariate regression analysis adjusted for age, D'Amico risk strata, comorbidities, and socioeconomic deprivation showed that Māori men were more likely to be managed expectantly [RR 1.74 (95 % CI 1.06, 2.57)].

CONCLUSION

Differences between Māori and NZ European men observed in the management of localised prostate cancer cannot be readily explained by patient characteristics, such as comorbidities or risk assessment at diagnosis. Poorer outcomes for Māori men may not only be related to later stage at diagnosis but differences in treatment modalities may also be a factor.

The role of transrectal ultrasound in the diagnosis of prostate cancer: new contributions

Objective

The present study was aimed at evaluating the contribution of transrectal prostate ultrasound in the screening for prostate neoplasias and in the guidance of prostate biopsies.

Materials and Methods

Prospective study developed over a one-year period. All the patients with indication for prostate biopsy were evaluated. Regardless of PSA values, the patients underwent ultrasound in order to identify suspicious nodules (confirmed by two observers). Sextant biopsy was subsequently performed. In cases of finding suspicious nodules, an additional puncture directed to such nodules was done.

Results

In a total of 155 cases the prevalence of malignancy was of 53%. Suspicious nodules were detected in 34 patients, and 25 where malignant (positive predictive value of 74%). The specificity and sensitivity for suspicious nodules were 88% and 31% respectively. Comparatively with the randomly obtained sextant specimens, the rate of findings of neoplasia was higher in the specimens obtained with puncture directed to the nodule (p = 0.032). No statistically significant difference was observed in the Gleason score for both types of specimens (p = 0.172).

Conclusion

The high positive predictive value and the high rate of findings of neoplasia in specimens of suspicious nodules should be taken into consideration in the future. The authors suggest a biopsy technique similar to the one described in the present study (sextant biopsy plus puncture directed to the suspicious nodule).

Overdetection in screening for prostate cancer

PURPOSE OF REVIEW

To describe mechanisms behind and extent of overdetection in prostate cancer screening as well as possible ways to avoid unnecessary overdiagnosis.

RECENT FINDINGS

Overdetection and overtreatment is common in many areas of modern medicine. Current prostate-specific antigen (PSA) testing has resulted in a marked stage shift to early stages, which, together with improvements in treatment, has resulted in a substantial decrease in prostate cancer mortality. However, nonselective, widespread PSA-testing followed by liberal biopsy criteria has resulted in a high rate of overdiagnosis, which constitutes one major obstacle to introducing population-based screening.

SUMMARY

Several steps are needed to decrease overdetection: do not screen elderly men unlikely to benefit, do not biopsy without a compelling reason, differentiate screening interval according to risk, work-up benign prostate disease by using reflex tests and/or complementary biomarkers, and focus on screening men at high risk for a life-threatening disease, for example evaluate men with above-median PSA levels in midlife. Recent results indicate that use of MRI to select men for biopsy and using only lesion-directed biopsies may be one way forward. However, more studies are needed before firm recommendations can be made. When the diagnosis is made, treat only those who need treatment. Tailor treatment to tumor biology and patient characteristics, and offer active surveillance to eligible men with low-risk tumors, especially small-volume disease, as the first management.

A reference set of health utilities for long-term survivors of prostate cancer: population-based data from Ontario, Canada

PURPOSE

To measure quality of life (QOL) and utilities for prostate cancer (PC) patients and determine their predictors.

METHODS

A population-based, community-dwelling, geographically diverse sample of long-term PC survivors in Ontario, Canada, was identified from the Ontario Cancer Registry and contacted through their referring physician. Consenting patients completed questionnaires by mail: Health Utilities Index (HUI 2/3), Patient Oriented Prostate Utility Scale PORPUS-U (utility), PORPUS-P (health profile), Functional Assessment of Cancer Therapy-Prostate (FACT-P), and Prostate Cancer Index (PCI). Clinical data were obtained from chart reviews. Regression models determined the effects of a series of variables on QOL and utility.

RESULTS

We received questionnaires and reviewed charts for 585 patients (mean age 72.6, 2-13 years postdiagnosis). Mean utility scores were as follows: PORPUS-U = 0.92, HUI2 = 0.85, and HUI3 = 0.78. Mean health profile scores were as follows: PORPUS-P = 71.7, PCI sexual, urinary, and bowel function = 23.7, 79.1, and 84.6, respectively (0 = worst, 100 = best), and FACT-P = 125.1 (0 = worst, 156 = best). In multiple regression analyses, comorbidity and PCI urinary, sexual, and bowel function were significant predictors of other QOL measures. With all variables, 32-50 % of the variance in utilities was explained.

CONCLUSIONS

Many variables affect global QOL of PC survivors; only prostate symptoms and comorbidity have independent effects. Our model allows estimation of the effects of multiple factors on utilities. These utilities for long-term outcomes of PC and its treatment are valuable for decision/cost-effectiveness models of PC treatment.

Imaging-guided prostate biopsy: conventional and emerging techniques

Transrectal ultrasonography (US)-guided biopsy is the standard approach for histopathologic diagnosis of prostate cancer. However, this technique has multiple limitations owing to the operator's inability in most cases to directly visualize and target prostate lesions. Magnetic resonance (MR) imaging of the prostate overcomes many of these limitations by directly depicting areas of abnormality and allowing targeted biopsies. Accuracy in the detection of prostate cancer is improved by the combined use of standard T2-weighted MR imaging and advanced MR imaging techniques such as diffusion-weighted imaging, dynamic contrast-enhanced imaging, and MR spectroscopy. Suspicious-appearing regions of the prostate seen on MR images can be targeted at real-time transrectal US-guided biopsy to improve the diagnostic yield. MR imaging also can be performed for real-time guidance of transrectal prostate biopsy. Studies among patients who underwent at least one transrectal US-guided biopsy with a negative result before undergoing an MR imaging-guided biopsy showed improved detection rates with MR imaging-guided biopsy in comparison with the detection rates achieved with a repeat transrectal US-guided biopsy; however, MR imaging-guided biopsy is a more time-consuming procedure. A technique known as fused MR imaging- and transrectal US-guided biopsy, which relies on the coregistration of previously acquired MR images with real-time transrectal US images acquired during the procedure, shows promise but is limited by deformation of the prostate; this limitation is the subject of ongoing investigation. Another technique that is currently under investigation, MR imaging-guided prostate biopsy with robotic assistance, may one day help improve the accuracy of biopsy needle placement.

Diagnostic performance of PCA3 to detect prostate cancer in men with increased prostate specific antigen: a prospective study of 1,962 cases

PURPOSE

The detection of prostate cancer relies primarily on abnormal digital rectal examination or increased serum prostate specific antigen concentration. However, low positive predictive values result in many men with increased prostate specific antigen and/or suspicious digital rectal examination having a negative biopsy. We investigated the value of the PCA3 (prostate cancer gene 3) urine test in predicting the likelihood of diagnosis of cancer before biopsy.

MATERIALS AND METHODS

We performed a prospective, community based clinical trial to evaluate PCA3 score before any biopsy. This trial was conducted at 50 urology practices in the United States. Samples were obtained from 1,962 men with increased serum prostate specific antigen (greater than 2.5 ng/ml) and/or abnormal digital rectal examination before transrectal prostate needle biopsy. Study samples (urinary PCA3 and biopsies) were processed and analyzed by a central laboratory. Sensitivity-specificity analyses were conducted.

RESULTS

A total of 1,913 urine samples (97.5%) were adequate for PCA3 testing. Of 802 cases diagnosed with prostate cancer 222 had high grade prostatic intraepithelial neoplasia or atypical small acinar proliferation and were suspicious for cancer, whereas 889 cases were benign. The traditional PCA3 cutoff of 35 reduced the number of false-positives from 1,089 to 249, a 77.1% reduction. However, false-negatives (missed cancers) increased significantly from 17 to 413, an increase of more than 2,300%. Lowering the PCA3 cutoff to 10 reduced the number of false-positives 35.4% and false-negatives only increased 5.6%.

CONCLUSIONS

Urinary PCA3 testing in conjunction with prostate specific antigen has the potential to significantly decrease the number of unnecessary prostate biopsies.

Cell surface glycoproteomic analysis of prostate cancer-derived PC-3 cells

Most clinically approved biomarkers of cancer are glycoproteins, and those residing on the cell surface are of particular interest in biotherapeutics. We report a method for selective labeling, affinity enrichment, and identification of cell-surface glycoproteins. PC-3 cells and primary human prostate cancer tissue were treated with peracetylated N-azidoacetylgalactosamine, resulting in metabolic labeling of cell surface glycans with the azidosugar. We used mass spectrometry to identify over 70 cell surface glycoproteins and biochemically validated CD146 and integrin beta-4, both of which are known to promote metastatic behavior. These results establish cell-surface glycoproteomics as an effective technique for discovery of cancer biomarkers.

Quantitative metric profiles capture three-dimensional temporospatial architecture to discriminate cellular functional states

BACKGROUND

Computational analysis of tissue structure reveals sub-visual differences in tissue functional states by extracting quantitative signature features that establish a diagnostic profile. Incomplete and/or inaccurate profiles contribute to misdiagnosis.

METHODS

In order to create more complete tissue structure profiles, we adapted our cell-graph method for extracting quantitative features from histopathology images to now capture temporospatial traits of three-dimensional collagen hydrogel cell cultures. Cell-graphs were proposed to characterize the spatial organization between the cells in tissues by exploiting graph theory wherein the nuclei of the cells constitute the nodes and the approximate adjacency of cells are represented with edges. We chose 11 different cell types representing non-tumorigenic, pre-cancerous, and malignant states from multiple tissue origins.

RESULTS

We built cell-graphs from the cellular hydrogel images and computed a large set of features describing the structural characteristics captured by the graphs over time. Using three-mode tensor analysis, we identified the five most significant features (metrics) that capture the compactness, clustering, and spatial uniformity of the 3D architectural changes for each cell type throughout the time course. Importantly, four of these metrics are also the discriminative features for our histopathology data from our previous studies.

CONCLUSIONS

Together, these descriptive metrics provide rigorous quantitative representations of image information that other image analysis methods do not. Examining the changes in these five metrics allowed us to easily discriminate between all 11 cell types, whereas differences from visual examination of the images are not as apparent. These results demonstrate that application of the cell-graph technique to 3D image data yields discriminative metrics that have the potential to improve the accuracy of image-based tissue profiles, and thus improve the detection and diagnosis of disease.

Randomised prostate cancer screening trial: 20 year follow-up

OBJECTIVE

To assess whether screening for prostate cancer reduces prostate cancer specific mortality.

DESIGN

Population based randomised controlled trial.

SETTING

Department of Urology, Norrköping, and the South-East Region Prostate Cancer Register.

PARTICIPANTS

All men aged 50-69 in the city of Norrköping, Sweden, identified in 1987 in the National Population Register (n = 9026).

INTERVENTION

From the study population, 1494 men were randomly allocated to be screened by including every sixth man from a list of dates of birth. These men were invited to be screened every third year from 1987 to 1996. On the first two occasions screening was done by digital rectal examination only. From 1993, this was combined with prostate specific antigen testing, with 4 µg/L as cut off. On the fourth occasion (1996), only men aged 69 or under at the time of the investigation were invited.

MAIN OUTCOME MEASURES

Data on tumour stage, grade, and treatment from the South East Region Prostate Cancer Register. Prostate cancer specific mortality up to 31 December 2008.

RESULTS

In the four screenings from 1987 to 1996 attendance was 1161/1492 (78%), 957/1363 (70%), 895/1210 (74%), and 446/606 (74%), respectively. There were 85 cases (5.7%) of prostate cancer diagnosed in the screened group and 292 (3.9%) in the control group. The risk ratio for death from prostate cancer in the screening group was 1.16 (95% confidence interval 0.78 to 1.73). In a Cox proportional hazard analysis comparing prostate cancer specific survival in the control group with that in the screened group, the hazard ratio for death from prostate cancer was 1.23 (0.94 to 1.62; P = 0.13). After adjustment for age at start of the study, the hazard ratio was 1.58 (1.06 to 2.36; P = 0.024).

CONCLUSIONS

After 20 years of follow-up the rate of death from prostate cancer did not differ significantly between men in the screening group and those in the control group. Trial registration Current Controlled Trials, ISRCTN06342431.

Mortality results from the Göteborg randomised population-based prostate-cancer screening trial

BACKGROUND

Prostate cancer is one of the leading causes of death from malignant disease among men in the developed world. One strategy to decrease the risk of death from this disease is screening with prostate-specific antigen (PSA); however, the extent of benefit and harm with such screening is under continuous debate.

METHODS

In December, 1994, 20,000 men born between 1930 and 1944, randomly sampled from the population register, were randomised by computer in a 1:1 ratio to either a screening group invited for PSA testing every 2 years (n=10,000) or to a control group not invited (n=10,000). Men in the screening group were invited up to the upper age limit (median 69, range 67-71 years) and only men with raised PSA concentrations were offered additional tests such as digital rectal examination and prostate biopsies. The primary endpoint was prostate-cancer specific mortality, analysed according to the intention-to-screen principle. The study is ongoing, with men who have not reached the upper age limit invited for PSA testing. This is the first planned report on cumulative prostate-cancer incidence and mortality calculated up to Dec 31, 2008. This study is registered as an International Standard Randomised Controlled Trial ISRCTN54449243.

FINDINGS

In each group, 48 men were excluded from the analysis because of death or emigration before the randomisation date, or prevalent prostate cancer. In men randomised to screening, 7578 (76%) of 9952 attended at least once. During a median follow-up of 14 years, 1138 men in the screening group and 718 in the control group were diagnosed with prostate cancer, resulting in a cumulative prostate-cancer incidence of 12.7% in the screening group and 8.2% in the control group (hazard ratio 1.64; 95% CI 1.50-1.80; p<0.0001). The absolute cumulative risk reduction of death from prostate cancer at 14 years was 0.40% (95% CI 0.17-0.64), from 0.90% in the control group to 0.50% in the screening group. The rate ratio for death from prostate cancer was 0.56 (95% CI 0.39-0.82; p=0.002) in the screening compared with the control group. The rate ratio of death from prostate cancer for attendees compared with the control group was 0.44 (95% CI 0.28-0.68; p=0.0002). Overall, 293 (95% CI 177-799) men needed to be invited for screening and 12 to be diagnosed to prevent one prostate cancer death.

INTERPRETATION

This study shows that prostate cancer mortality was reduced almost by half over 14 years. However, the risk of over-diagnosis is substantial and the number needed to treat is at least as high as in breast-cancer screening programmes. The benefit of prostate-cancer screening compares favourably to other cancer screening programs.

FUNDING

The Swedish Cancer Society, the Swedish Research Council, and the National Cancer Institute.