WHAT'S NEW THIS TUESDAY: FOUR ON CANCER PREVENTION IN DEVELOPING COUNTRIES

Friday, 21st of September 2012

•     FOUR ON CANCER PREVENTION IN DEVELOPING COUNTRIES

Clinical oncology is still in its infancy in many parts of the world. While treatment resources remain scarce, poor countries will need to look for cheap, cost-effective ways of preventing cancer.

The first of these, available for many decades, is prevention of lung and pancreatic cancers through reduction of tobacco use. The second, now in its third decade, is hepatitis B vaccination for prevention of liver cancer. A recent entrant among vaccines is HPV for prevention of cervical cancer. The article by Frieden and colleagues, writing in Oncology, covers these and other topics.

Often omitted from this list is male circumcision.  From The Lancet/Oncology comes a discussion on whether male circumcision could reduce the cancer load.

• GLOBAL BURDEN OF CANCERS ATTRIBUTABLE TO INFECTIONS

Global burden of cancers attributable to infections in 2008: a review and synthetic analysis

Lancet Oncol. 2012 Jun;13(6):607-15. Epub 2012 May 9.

de Martel C, Ferlay J, Franceschi S, Vignat J, Bray F, Forman D, Plummer M.

Source

International Agency for Research on Cancer, Lyon, France.

Abstract below; full text is at http://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(12)70137-7/fulltext

BACKGROUND:

Infections with certain viruses, bacteria, and parasites have been identified as strong risk factors for specific cancers. An update of their respective contribution to the global burden of cancer is warranted.

METHODS:

We considered infectious agents classified as carcinogenic to humans by the International Agency for Research on Cancer. We calculated their population attributable fraction worldwide and in eight geographical regions, using statistics on estimated cancer incidence in 2008. When associations were very strong, calculations were based on the prevalence of infection in cancer cases rather than in the general population. Estimates of infection prevalence and relative risk were extracted from published data.

FINDINGS:

Of the 12·7 million new cancer cases that occurred in 2008, the population attributable fraction (PAF) for infectious agents was 16·1%, meaning that around 2 million new cancer cases were attributable to infections. This fraction was higher in less developed countries (22·9%) than in more developed countries (7·4%), and varied from 3·3% in Australia and New Zealand to 32·7% in sub-Saharan Africa. Helicobacter pylori, hepatitis B and C viruses, and human papillomaviruses were responsible for 1·9 million cases, mainly gastric, liver, and cervix uteri cancers. In women, cervix uteri cancer accounted for about half of the infection-related burden of cancer; in men, liver and gastric cancers accounted for more than 80%. Around 30% of infection-attributable cases occur in people younger than 50 years.

INTERPRETATION:

Around 2 million cancer cases each year are caused by infectious agents. Application of existing public health methods for infection prevention, such as vaccination, safer injection practice, or antimicrobial treatments, could have a substantial effect on the future burden of cancer worldwide.

FUNDING:

Fondation Innovations en Infectiologie (FINOVI) and the Bill & Melinda Gates Foundation (BMGF).

Copyright © 2012 Elsevier Ltd. All rights reserved.

Comment in Global burden of infection-related cancer revisited. [Lancet Oncol. 2012]

• CANCER CONTROL IN DEVELOPING COUNTRIES

Cancer control in developing countries: using health data and health services research to measure and improve access, quality and efficiency

Full text, http://www.biomedcentral.com/1472-698X/10/24

Timothy P Hanna1* and Alfred CT Kangolle2

* Corresponding author: Timothy P Hanna tim.hanna@hotmail.com

Abstract

Background

Cancer is a rapidly increasing problem in developing countries. Access, quality and efficiency of cancer services in developing countries must be understood to advance effective cancer control programs. Health services research can provide insights into these areas.

Discussion

This article provides an overview of oncology health services in developing countries. We use selected examples from peer-reviewed literature in health services research and relevant publicly available documents. In spite of significant limitations in the available data, it is clear there are substantial barriers to access to cancer control in developing countries. This includes prevention, early detection, diagnosis/treatment and palliation. There are also substantial limitations in the quality of cancer control and a great need to improve economic efficiency. We describe how the application of health data may assist in optimizing (1) Structure: strengthening planning, collaboration, transparency, research development, education and capacity building. (2) Process: enabling follow-up, knowledge translation, patient safety and quality assurance. (3) Outcome: facilitating evaluation, monitoring and improvement of national cancer control efforts. There is currently limited data and capacity to use this data in developing countries for these purposes.

Summary

There is an urgent need to improve health services for cancer control in developing countries. Current resources and much-needed investments must be optimally managed. To achieve this, we would recommend investment in four key priorities: (1) Capacity building in oncology health services research, policy and planning relevant to developing countries. (2) Development of high-quality health data sources. (3) More oncology-related economic evaluations in developing countries. (4) Exploration of high-quality models of cancer control in developing countries. Meeting these needs will require national, regional and international collaboration as well as political leadership. Horizontal integration with programs for other diseases will be important.

• A PUBLIC HEALTH APPROACH TO CANCER

‘A Public Health Approach to Winning the War against Cancer,’

Oncologist. 2008 Dec;13(12):1306-13. Epub 2008 Dec 17

Frieden TR, Myers JE, Krauskopf MS, Farley TA.

New York City Department of Health and Mental Hygiene, New York, NY 10013 USA.

The "war on cancer" in the United States has been viewed primarily as an effort to develop and disseminate cancer cures, but cancer is far more easily prevented than cured. There are three major approaches to cancer prevention: Primary prevention, through reduction in risk factors and changes to the environment that reduce human exposure to widely-consumed cancer-promoting agents. The most important actions for primary prevention of cancer are those that reduce tobacco use through taxation, smoke-free environment policies, advertising restrictions, counter-advertising, and cessation programs. The World Health Organization's MPOWER package outlines these actions, each of which covered less than 5% of people in the world in 2007. Similarly, cancer can be prevented by reducing alcohol consumption through policies such as alcohol taxes and limits on alcohol sales, and restoring caloric balance through policies such as creating healthier food environments and engineering the built environment to increase opportunities for physical activity. Vaccination is an effective approach to preventing specific virus-associated cancers, such as using human papillomavirus vaccine to prevent cervical cancer and hepatitis B virus vaccine to prevent hepatocellular cancer. Secondary prevention reduces cancer mortality through screening and early treatment; this approach has been used successfully for breast and cervical cancer but is still underused against colon cancer. Progress can be made in all three approaches to cancer prevention, but will require a greater emphasis on public health programs and public policy. Winning the war on cancer will require a much larger investment in prevention to complement efforts to improve treatment.

• MALE CIRCUMCISION: A CANCER PREVENTION STRATEGY?

 outline goes here

Male circumcision: a cancer prevention strategy?

The Lancet Oncology, Volume 10, Issue 5, Page 431, May 2009

On March 26, 2009, the New England Journal of Medicine reported findings from a Ugandan trial on the effect of male circumcision on the prevalence of viral sexually transmitted infections, showing reduced incidence of HSV2 infection by 25% and of HPV infection by 35%. Previously, the same study group reported that male circumcision decreased HIV infection by 50—60%. In low-to-middle income countries cancer burden is increasing substantially, and infection is often the underlying cause. Given that less than 20% of males are circumcised in many developing countries, and that male circumcision is relatively simple and reduces viral infection, might this practice be more widely used as a preventive measure against cancer?

HPV and HIV associated cancers are responsible for a considerable number of cancer deaths in low-to-middle income countries. Cancers such as Kaposi's sarcoma and cervical cancer are well-recognised, but equally important are lymphoma, and carcinomas of the head and neck, penis, anus, and vulva. Additionally, developing countries have to face other challenges such as a paucity of screening, late presentation and difficulty of implementing effective interventions, and maintaining patients' follow-up—all compounded by lack of resource and infrastructure. Thus, prevention is more crucial than cure.

In developing countries, male circumcision could thus have a vital role in specific segments of the population. However, if circumcision is to be considered a prevention strategy, a number of questions will need detailed thought and investigation. First, scientific questions remained unanswered: how, precisely, is circumcision protective—what are the biological mechanisms? Does decreased viral acquisition or duration of infection or shedding actually reduce cancer incidence? Will this reduction translate easily to a protective effect in sexual partners? Second, questions related to infrastructure also need consideration. As a one-time surgical procedure, male circumcision is likely to be more feasible and cost effective than other virus prevention strategies, such as vaccination or screening, which require several visits. However, cost-effectiveness and modelling data are needed to provide suitable supportive evidence, and studies need to be done to estimate the potential population-level benefit of the procedure.

Wide-scale implementation of male circumcision also raises cultural, ethical, legal, and human rights issues. The easiest way to effectively implement the strategy—ie, in young infants—would take at least one generation before any prevention effect becomes measurable and raises ethical issues surrounding a child's body integrity and of consent. Male circumcision can also have symbolic meanings that raise additional barriers: it is sometimes seen as a traditional practice with religious or cultural significance, or a practice related to hygiene, or simply unfamiliar and foreign.

Despite these issues, lessons can be learned from programmes on HIV prevention. Since 2007, WHO/UNAIDS have recommended safe and voluntary male circumcision as an important strategy for the prevention of HIV infection in areas with high prevalence and low levels of male circumcision. This programme has been reasonably well-received, suggesting that uptake of male circumcision is not as contentious as one might think. Indeed, cancer prevention strategies in developing countries are often limited and have to compete against HIV for funding, but existence of the WHO/UNAIDS programme could bring a welcome secondary benefit of cancer prevention and could also allow rollout of more comprehensive cancer prevention measures via piggy-backing on existing infrastructure. Monitoring incidence of HIV-associated cancer among men currently being circumcised for HIV containment within the WHO/UNAIDS programme would provide useful insight into the possible effectiveness circumcision might offer against HPV-associated cancers.

Any intervention should be locally relevant and evidence-based. Discussions around male circumcision strategies should be encouraged within the context of cancer prevention, and these should include local communities alongside assessments of current capacities, measurable targets, cost analyses and modelling, and the development of practicable guidelines, so as to place male circumcision within the possible options available for disease prevention.