Prostate cancer screening; is this a teachable moment?

Meeting the global demands of epidemiologic transition - the indispensable role of cancer prevention

The number of new cancer cases each year is projected to rise worldwide by about 70% by 2030 due to demographic changes alone, with the largest increases in the lower-income countries. Wider adoption of specific aspects of westernized lifestyles would translate to still greater increases in certain cancer types. In many countries the burden of cancer and other non-communicable diseases will add to communicable diseases and malnutrition to impose a "double burden" on the poorest. These trends represent major challenges to health, poverty, sustainable development and equality. Prevention is, however, possible based on implementing existing knowledge about risk factors and the natural history of the disease. Both primary and secondary cancer prevention offer therefore many opportunities to combat the projected increases. Tobacco control, reductions in obesity and physical inactivity, reduced consumption of alcohol, vaccination against hepatitis B and human papilloma viruses, safe sex, avoidance of environmental and occupational carcinogens and excessive sun exposure as well as the early detection and screening for breast, cervix and colorectal cancers would all make significant contributions. At the same time, for a number of major cancers (e.g., colon, prostate, kidney, pancreas, brain, lympho-haematological malignancies) research is needed to identify as yet unknown risk factors whilst for existing prevention strategies additional work is needed on their implementation into health services. Finally, there is a remarkable opportunity for advances in understanding the molecular basis of carcinogenesis to provide new tools and insights into aetiology and prevention. It is only by complementing efforts to improve treatment with those aimed at prevention that the impending epidemic of this disease can be addressed.

Cancer in the Azores: initial results from a recently established population-based cancer registry

INTRODUCTION: The Azores archipelago has long been the Portuguese region that presents the highest mortality rates for certain cancers. Lack of incidence data has prevented the evaluation of the actual burden of this disease in the Azorean population. METHODS: Malignant tumours (ICD-O 5th Digit /3) initially diagnosed between the January 1st 2000 and December 31st 2002 were retrieved from the database of the recently established population-based cancer registry. Crude, age-specific and age-standardized rates were calculated and confidence intervals were estimated using Poisson approximation. Relative risks of developing cancer in the Azores when compared to mainland Portugal have been represented by standardized ratios. Quality indicators, including Mortality:Incidence (M:I) ratios, were also assessed. RESULTS: Overall, the data shows a high incidence rate for some malignant diseases, specifically in men. Compared to those living in mainland Portugal, both Azorean men (RR 1.412; 99% CI 1.407-1.416) and women (1.127; 1.125-1.129) presented a significantly higher risk of developing cancer, all sites combined. When compared with other cancer registries, a less favourable cancer survival pattern is reported in the Azores, as emphasized by higher M:I ratios for several cancer sites. CONCLUSIONS: A preliminary analysis of the results suggests the presence of some major risk factors in the Azorean population, namely tobacco smoking in men. Higher M:I ratios would also point to survival disparities between the Azores archipelago and the continent, which should be further studied.

The impact of PSA screening on prostate cancer mortality and overdiagnosis of prostate cancer in the United States

BACKGROUND

The study assessed the impact of prostate-specific antigen (PSA) testing in the United States by comparing the rates of PSA testing in U.S. counties to the rates of prostate biopsies and newly treated prostate cancer and to deaths from prostate cancer.

METHODS

We examined the association between the percentage of men aged 66-74 from a nationally representative 5% Medicare sample who received PSA testing in each U.S. county in 1997 and the percent of men who received prostate biopsies or treatment for newly diagnosed prostate cancer in 1997 as well as mortality from prostate cancer and from all other causes from 1998 to 2007.

RESULTS

Analyses of 1,067 U.S. counties showed a significant relationship between the rate of PSA testing and both the rate of men undergoing treatment for prostate cancer and prostate cancer mortality (both p < .001) but no relationship with mortality from other causes. For every 100,000 men receiving a PSA test in 1997, an additional 4,894 men underwent prostate biopsy and 1,597 additional men underwent prostate cancer treatment in 1997, and 61 fewer men died from prostate cancer during 1998-2006. Analyses stratified by age and race produced similar results.

CONCLUSIONS

PSA testing was associated with modest reductions in prostate cancer mortality and large increases in the number of men overdiagnosed with and overtreated for prostate cancer. The results are similar to those obtained by the large European randomized prospective trial of PSA testing.

Changes in incidence, survival and mortality of prostate cancer in Europe and the United States in the PSA era: additional diagnoses and avoided deaths

BACKGROUND

We describe changes in prostate cancer incidence, survival and mortality and the resulting impact in additional diagnoses and avoided deaths in European areas and the United States.

METHODS

Using data from 12 European cancer registries and the Surveillance, Epidemiology and End Results program, we describe changes in prostate cancer epidemiology between the beginning of the PSA era (USA: 1985-1989, Europe: 1990-1994) and 2002-2006 among patients aged 40-64, 65-74, and 75+. Additionally, we examine changes in yearly numbers of diagnoses and deaths and variation in male life expectancy.

RESULTS

Incidence and survival, particularly among patients aged <75, increased dramatically, yet both remain (with few exceptions in incidence) lower in Europe than in the United States. Mortality reductions, ongoing since the mid/late 1990 s, were more consistent in the United States, had a distressingly small absolute impact among patients aged 40-64 and the largest absolute impact among those aged 75+. Overall ratios of additional diagnoses/avoided deaths varied between 3.6 and 27.6, suggesting large differences in the actual impact of prostate cancer incidence and mortality changes. Ten years of remaining life expectancy was reached between 68 and 76 years.

CONCLUSION

Policies reflecting variation in population life expectancy, testing preferences, decision aids and guidelines for surveillance-based management are urgently needed.

Time for a strategic research response to anal cancer

Anal cancer was until recently regarded as a rare cancer of little consequence. The articles in this special edition of Sexual Health clearly demonstrate that anal cancer is increasing in incidence and, in some populations, it has become an urgent public health priority. In this summary paper, we will review the data presented in this issue and elsewhere on the magnitude of the issue, the means of prevention and treatment, and suggest a way forward.

Uninformed compliance or informed choice? A needed shift in our approach to cancer screening

It has been more than 30 years since the first consensus development meeting was held to deal with guidelines of mammography screening. Although the National Cancer Institute has wisely focused on the science of screening and of screening benefits vs harm, many professional organizations, advocacy groups, and the media have maintained a focus on establishing who should be screened and promoting recommendations for which age groups should be screened. Guidelines have been developed not only for mammography but also for screening at virtually all major cancer sites, especially for prostate cancer, and most recently, with the preliminary results of the National Lung Screening Trial, for lung cancer. It seems clear that we have done an inadequate job of educating screening candidates about the harms and benefits of cancer screening, including the extent to which screening can reduce cancer mortality. We must also question whether our practice of summoning women to have mammograms, while providing men informed choice for prostate cancer screening, is consistent with a scientific analysis of the relative harms and benefits. We have spent a staggering amount of time and energy over the past several decades developing, discussing, and debating guidelines. Professional and advocacy groups have spent much time aggressively advocating the adoption of guidelines supported by their respective groups. It seems that it would be much more productive to devote such energy to educating screening candidates about the harms and benefits of screening and to engaging in shared decision making.

African American men significantly underestimate their risk of having prostate cancer at the time of biopsy

BACKGROUND

Guidelines for prostate cancer (PCa) screening recommend physicians to have an informational discussion with patients. At the time of biopsy, patients should be informed of their heightened PCa risk, particularly African Americans (AA) who have significantly higher diagnostic and mortality risk. We tested predictors of patients' estimation of their likelihood of having PCa at the time of biopsy.

METHODS

A convenience sample of AA (n = 207) and white (n = 271) biopsy patients was surveyed at the time of prostate biopsy. Participants gave likelihood estimations of having PCa and data on their socio-demographics, health, clinical status, and general and PCa-specific anxiety. Binary logistic regressions tested for predictors of the patients' estimations and biopsy results.

RESULTS

Fifty-one percent of AA men answered that they had a '0%' likelihood of having PCa versus 19% of whites, whereas 57% of AA men had abnormal biopsies compared with 42% of whites. In logistic regressions, predictors of patient answers of 0% chance of PCa were AA ethnicity (OR = 4.50; p < 0.001), lower cancer-specific anxiety (OR = 0.93; p < 0.01), less education (OR = 2.38; p < 0.05), and less urinary disturbance (OR = 0.70; p < .05). In a second regression, AA patients trended towards higher positive biopsy rates (OR = 1.43; p = 0.17).

CONCLUSIONS

At biopsy, AA more often estimated their likelihood of PCa as 0%, despite higher risks. Reasons for these low estimates and their potential contribution to poor treatment outcomes of AA patients require further investigation.

Prostate Cancer Screening and the PSA Test

‘What about that article in the Guardian about the study on the PSA test? Can I please have the new urine test (PCA3) instead? Will I be OK if the test result is normal?’ are the kind of questions that I have been asked about the prostate cancer screening and the prostate-specific antigen (PSA) test. This article should help the reader to have an informed discussion with men requesting the PSA test.

High-throughput screen identifies novel inhibitors of cancer biomarker α-methylacyl coenzyme A racemase (AMACR/P504S)

α-methylacyl coenzyme A racemase (AMACR) is a metabolic enzyme whose overexpression has been shown to be a diagnostic indicator of prostatic adenocarcinoma and other solid tumors. Here, we confirm that attenuation of AMACR expression diminishes the growth of prostate cancer cell lines by using stably expressed short-hairpin RNA constructs. This observation strongly suggests that the AMACR enzyme may be a target for therapeutic inhibition in prostate cancer. To this end, we report here a novel assay capable of screening libraries of diverse small molecules for inhibitors of AMACR activity. This assay facilitated the screening of approximately 5,000 unique compounds and the discovery of 7 distinct chemical entities capable of inhibiting AMACR at low micromolar concentrations. The most potent inhibitor discovered is the seleno-organic compound ebselen oxide [inhibitory concentration (IC(50)): 0.80 μmol/L]. The parent compound, ebselen (IC(50): 2.79 μmol/L), is a covalent inactivator of AMACR (K(I)((inact)): 24 μmol/L). Two of the AMACR inhibitors are selectively toxic to prostate cancer cell lines (LAPC4/LNCaP/PC3) that express AMACR compared to a normal prostate fibroblast cell line (WPMY1) that does not express the protein. This report shows the first high-throughput screen for the discovery of novel AMACR inhibitors, characterizes the first nonsubstrate-based inhibitors, and validates that AMACR is a viable chemotherapeutic target in vitro.

Gastrin-releasing peptide receptor-based targeting using bombesin analogues is superior to metabolism-based targeting using choline for in vivo imaging of human prostate cancer xenografts

Purpose

Prostate cancer (PC) is a major health problem. Overexpression of the gastrin-releasing peptide receptor (GRPR) in PC, but not in the hyperplastic prostate, provides a promising target for staging and monitoring of PC. Based on the assumption that cancer cells have increased metabolic activity, metabolism-based tracers are also being used for PC imaging. We compared GRPR-based targeting using the ⁶⁸Ga-labelled bombesin analogue AMBA with metabolism-based targeting using ¹⁸F-methylcholine (¹⁸F-FCH) in nude mice bearing human prostate VCaP xenografts.

Methods

PET and biodistribution studies were performed with both ⁶⁸Ga-AMBA and ¹⁸F-FCH in all VCaP tumour-bearing mice, with PC-3 tumour-bearing mice as reference. Scanning started immediately after injection. Dynamic PET scans were reconstructed and analysed quantitatively. Biodistribution of tracers and tissue uptake was expressed as percent of injected dose per gram tissue (%ID/g).

Results

All tumours were clearly visualized using ⁶⁸Ga-AMBA. ¹⁸F-FCH showed significantly less contrast due to poor tumour-to-background ratios. Quantitative PET analyses showed fast tumour uptake and high retention for both tracers. VCaP tumour uptake values determined from PET at steady-state were 6.7 ± 1.4%ID/g (20–30 min after injection, N = 8) for ⁶⁸Ga-AMBA and 1.6 ± 0.5%ID/g (10–20 min after injection, N = 8) for ¹⁸F-FCH, which were significantly different (p <0.001). The results in PC-3 tumour-bearing mice were comparable. Biodistribution data were in accordance with the PET results showing VCaP tumour uptake values of 9.5 ± 4.8%ID/g (N = 8) for ⁶⁸Ga-AMBA and 2.1 ± 0.4%ID/g (N = 8) for ¹⁸F-FCH. Apart from the GRPR-expressing organs, uptake in all organs was lower for ⁶⁸Ga-AMBA than for ¹⁸F-FCH.

Conclusion

Tumour uptake of ⁶⁸Ga-AMBA was higher while overall background activity was lower than observed for ¹⁸F-FCH in the same PC-bearing mice. These results suggest that peptide receptor-based targeting using the bombesin analogue AMBA is superior to metabolism-based targeting using choline for scintigraphy of PC.

Are treatments for cervical precancerous lesions in less-developed countries safe enough to promote scaling-up of cervical screening programs? A systematic review

Background

Since the mid-1990s, there have been growing efforts to prevent cervical cancer in less-developed countries through the development of innovative screening approaches such as visual inspection of the cervix associated with same day management of cervical lesions with cryotherapy or loop electrosurgical excision procedure (LEEP). In the past, promising cancer screening interventions have been widely promoted despite incomplete evidence, only to become the subject of intense controversies about ensuing net health benefit. Because the efficacy and effectiveness of the new protocols for global cervical cancer screening have not been well characterized yet, and as a contribution to the evaluation of the balance between the benefits and risks of these protocols, we reviewed the literature on the safety of cryotherapy and LEEP for cervical intraepithelial neoplasia (CIN) in low- and middle-income countries.

Methods

We searched 12 databases (Medline, Google Scholar, Scopus, Cochrane Library, Web of Science, OCLC, PAIS International Database, WHO Global Health Library, CINAHL, Science.gov, NYAM Grey Literature Report, and POPLINE) for original research published between January 1995 and April 2009. Both peer-reviewed publications and items of "grey" literature were retrieved; no language restriction was applied. We calculated the median (minimum, maximum) reported rate for each harm considered. Because of limitations and heterogeneity in the data, no formal meta-analysis was performed.

Results

The search identified 32 articles that reported safety data from 24 cryotherapy and LEEP studies. The combined sample consisted of 6,902 women treated by cryotherapy and 4,524 women treated by LEEP. Most studies were conducted in reference or research settings in Asia and Africa. Short-term harms of cryotherapy and LEEP appeared to be similar to those described in the literature from high-income countries. Information was sparse on HIV-related harms and long-term reproductive outcomes of treatment.

Conclusions

When performed in resource-limited settings by qualified providers, cryotherapy and LEEP are not associated with excess harm. However, available data are insufficient to propose fully evidence-based protocols for routine screening of HIV-infected women and women of reproductive age.