March 20, 2017 – Karen Emmons, Professor and Dean for Academic Affairs at Harvard T.H. Chan School of Public Health and an expert in cancer prevention interventions, says that knowledge we already have about ways to prevent cancer is not being used as effectively as it could be. Emmons and Graham Colditz of Washington University wrote about the issue in a recent NEJM opinion piece.
Research suggests that more than half of cancers could be prevented by applying knowledge we already have. Can you give an example or two of how strong evidence regarding cancer prevention is not being used effectively?
There are several different strategies that are effective at preventing cancer. Some approaches are medical—such as screening or vaccination. Others are environmental or policy based, aimed at reducing risky behavior and increasing access to treatment as well as increasing uptake of healthy alternatives.
The HPV vaccine is a great example of a medical strategy. There is strong evidence that the vaccine prevents cervical cancer. However, in the U.S. only 42% of girls and 28% of boys have received it. This contrasts with Australia, which provides the vaccine free to all women ages 12-26 and recommends vaccination for boys. As a result of this national approach, 77% of girls and 67% of boys in Australia are vaccinated by age 15. And within three years of implementing the HPV vaccination program, dramatic reductions in cervical lesions were documented, and this trend has continued over time.
A good example of a policy-based strategy is taxation on tobacco. There is strong evidence that tobacco taxes are associated with reductions in tobacco use, which is the primary cause of preventable cancers. The U.S. federal excise tax on tobacco is currently about one-third that of high-income countries worldwide—$1.01 versus $3.15 per pack. All 50 states have tobacco excise taxes, but there is significant variation in tax rates across the U.S.—Missouri has the lowest tobacco tax, only $.17. Thirty-two percent of states have a tobacco tax under $1, and a similar percentage have not raised their taxes in over 10 years. This is particularly puzzling at a time when cash-strapped states are looking for revenue sources—a tobacco tax is a revenue stream that actually improves population health, especially when at least some of those tax revenues are used to increase access to smoking cessation treatment. And smoking cessation treatment, of course, substantially decreases the health care costs associated with treating smokers with tobacco-related diseases.
What do you think are some of the main reasons that cancer prevention strategies aren’t used to their full potential in the U.S.?
One reason is access. Many people simply have not had access to the health care needed to participate in cancer prevention and screening. The Affordable Care Act (ACA) made strides in the right direction, by increasing insurance coverage and mandating coverage of prevention strategies as essential health benefits. Now that Congress is considering repealing and/or replacing the ACA, there is significant concern about the impact on access to preventive care, especially if large numbers of people become uninsured or the preventive care requirements are reduced.
A great example of the impact of access to treatment comes from MassHealth, the Massachusetts Medicaid Program which began coverage for comprehensive smoking cessation treatment in 2006. Within two years, 70,000 MassHealth subscribers had used the benefit—or 37% of all the state’s Medicaid smokers. The smoking prevalence among this group declined by 26%, the annual rate of admissions for heart attacks was reduced by 46%, and there was a 49% annualized decline in admissions for coronary artery disease. As a result, $3.12 in medical savings were realized for every dollar spent on the benefit. That is prevention in action!
A second factor is that businesses that stand to lose money if people reduce their risky health behaviors sometimes oppose efforts aimed at cancer prevention. There are many well-documented examples, including lobbying efforts by the tobacco, sugar-sweetened beverage, and tanning industries.
Third, social determinants contribute to unequal access to prevention strategies. For example, safety-net health centers play a critically important role in ensuring equitable access to cancer prevention programs, but given their extremely limited resources and high demand, it can be difficult to integrate evidence-based practices that require significant patient education and discussion, such as HPV vaccination, or resources that are not available on-site, such as specific cancer screenings.
Finally, science—and the evidence it produces—is not static. As new knowledge becomes available, it sometimes changes the recommendations for staying healthy. This can be frustrating to the public, and can be used to suggest that science does not have value—rather than the reality that scientific knowledge continues to evolve and improve. Communicating about how and why knowledge about prevention changes is something the field needs to do better.
Your NEJM article calls for more research to help us better understand how to implement existing knowledge about cancer prevention. Why is this research so important?
By implementing the evidence we have in hand right now, we can save lives and reduce the suffering of millions of people. And, unlike even a decade or two ago, we now have many different and better ways to prevent cancer. We know that these strategies work, and see the benefits where they are used.
A very important area for more research is to understand why there is so much variation in uptake of prevention strategies across the U.S. and in different settings. Do people in Missouri deserve fewer efforts to prevent tobacco-related cancer than people in New York? Do people in rural and Western states deserve less access to cancer screening? Of course not, yet these patterns persist.
As a nation we have invested heavily in cancer research. If that investment is to pay off, we must conduct research to determine how to reduce variation in the use of cancer prevention strategies and increase access to prevention for all populations. When we implement evidence-based prevention and screening programs correctly and for all populations, regardless of where they live and their ability to pay, we all benefit.