Prevention, not treatment, lowers death rates for cancer
Programs and funding shift to screening, prevention
First, the good news: Two major studies conclude that for the first time since the 1930s, cancer mortality rates are dropping across the board. And that trend is likely to continue.
The bad news is that modern cancer treatments have had little to do with it, experts say.
In fact, despite years of clinical research and trials testing new therapies, cancer treatments remain remarkably ineffective against most types of cancer, says John C. Bailar III, MD, PhD, an oncologist with the department of health studies at the University of Chicago and co-author of one of the studies. The only reasonable conclusion is to establish a "national commitment to [cancer] prevention, with a concomitant rebalancing of the focus and funding of research," Bailar contends.
According to the study conducted by Bailar and Heather Gornik, MD, an intern at Brigham Hospital in Boston, the cancer mortality rate leveled off in 1991, at 203 deaths per 100,000 people. Since then, it has dropped by about 1% each year. These findings are mirrored in a similar study conducted late last year by the Bethesda, MD-based National Cancer Institute (NCI), which concluded that the mortality rate had dropped by almost 3% between 1991 and 1995.
Bailar claims that these decreases in mortality can be attributed mainly to improved efforts at prevention and early detection, a view shared by Ben Hankey, chief of the cancer statistics branch at NCI. The primary factor, says Hankey, has been changing patterns in smoking behavior. Other factors include increased use of mammography screening for breast cancer and Pap tests for cervical cancer.
Prevention research lacks support
Interestingly, despite its apparently greater efficacy in reducing the number of cancer-related deaths, prevention research remains woefully underfunded by organizations such as the NCI, Bailar claims. "NCI is really dominated by research on treatment," says Bailar. "In fact, there appears to have been a fair amount of resistance within NCI to moving strongly in the direction of prevention. The recent increase in support of prevention research has been directed by Congress. It was not an internal move."
Barnett Kramer, MD, MPH, deputy director of the division of cancer prevention and control at NCI, counters that the institute maintains a "broad-based portfolio" of research efforts and that prevention research accounts for a full 38% of its budget, or about $910 million annually. "That includes the study of specific interventions, plus the process of carcinogenesis, epidemiology, linkage of risk factors to disease, plus genetics," says Kramer. He concedes, however, that under the more restricted definition of prevention as "intervening to disengage the cause from the disease," the budget percentage drops to about 10%.
Kramer argues that because cancer encompasses a wide range of diseases, it’s unwise to select one approach over another for all cases. "For example, it’s pretty clear that the dramatic decrease in testicular cancer mortality and in cancers that affect children is almost solely attributable to treatment," he says, while the drop in lung cancer mortality is due almost solely to prevention efforts. In response, Bailar contends that so few children get cancer that the decline there has had little overall impact on the mortality rate.
Another problem with focusing too strongly on prevention research, Kramer claims, is that it can take many years to realize benefits. For example, the surgeon general’s report linking tobacco to lung cancer, released in 1964, led to an immediate drop-off in smoking prevalence. "But it took between two and three decades for the [lung cancer] mortality rate to drop in men," Kramer says. "So there is a tremendous delay often even with successful strategies."
Society wants instant cures
As a result of such delays, prevention efforts, including basic research into the molecular causes of cancer, can be a hard sell, says Michael Krieger, senior project manager at Spectrascan Health Services, a disease management company based in Windsor, CT, focusing on breast cancer. (See related story about preventive cancer programs, p. 92.) "America is not a very patient society," he says. "Going ahead and saying we’re going to come up with better treatments gets a lot more publicity, and you’re able to measure results quicker. That’s why you see less funding for going in and finding causes, which you know can take a very long time to find."
The problem is that without such basic research and a thorough understanding of risk factors, it can be virtually impossible to effectively target prevention efforts. "The big deal here is that we don’t know how to prevent most of the common cancers," says Bailar. "There are a lot of ideas, but nothing that has been demonstrated to the point where you could ask the public to make big changes. And there are some where we really don’t even have ideas," such as pancreatic cancer and cancer of the stomach."
Also, Bailar adds, "We don’t know how to prevent breast cancer in any feasible way. We know that it’s correlated with reproductive history. But you can’t ask all the women of America to start having more kids and having them earlier to prevent breast cancer."
"Right now, what we know about prevention is rather primitive," agrees Paul Engstrom, MD, senior vice president for population science at Fox Chase Cancer Center in Philadelphia. For example, says Engstrom, while it’s known that lowering fat intake and eating more fiber can lower some people’s risk of developing certain cancers, it’s not fully understood exactly who benefits from such dietary changes. Nor is it understood how early in life one must make those changes, or how long it takes to realize benefits. "We don’t even know for sure what type of fiber is best," says Engstrom.
Even when researchers know what risk factors are associated with a particular type of cancer, it’s often difficult to formulate effective prevention strategies to educate patients and the public, says Ivor Benjamin, MD, assistant professor in the department of obstetrics and gynecology at the University of Pennsylvania Cancer Center in Philadelphia.
"There are things like cervical cancer that we should have wiped out by now, but we haven’t," says Benjamin. The Pap test, he says, is a reliable screening test capable of detecting cervical cancer early on, and early treatment of cervical cancer is generally very effective. "So why do we still have people dying of cervical cancer?"
Benjamin claims that the problem is a failure on the part of caregivers to effectively communicate with patients and the public. "It’s one thing to get the word out to underserved areas," says Benjamin. "But what if patients don’t agree with what we’re telling them? We might not be putting forth a convincing enough argument or not giving them enough information to make an informed decision about it. I don’t think we can be so paternalistic as to say, You’ve got to have a Pap test because it’s good for you.’"
Much of the problem lies with physicians themselves, Engstrom says. For example, Fox Chase has conducted surveys of primary care physicians who claim not to have enough time to provide the evaluation and education necessary to discourage patients from smoking. He says it has been estimated that it would take about three minutes of a physician’s time to determine whether a patient smokes, whether he wants to quit, and then to provide him with materials detailing techniques for quitting.
"Most doctors tell us they can’t afford to take an extra few minutes per patient to do that," says Engstrom. "And yet there’s good research that shows that time spent identifying a smoker and getting him to stop is probably the most cost-efficient thing that a physician can do to prevent disease." Managed care plans also can do more by emphasizing screening and making low-cost screening and follow-up available to plan members, says Engstrom.
The bottom line, Benjamin says, is that the amount of money spent on cancer treatment has yielded a dismal return on investment. It’s become clear that "screening and prevention are where the money should go. A lot of that would be dissemination of information to the public and to primary care providers who might not be providing adequate screening," Benjamin says. "Just getting the word out might have a significant impact."
[For more information about cancer prevention, contact:
John C. Bailar III, MD, PhD, department of health studies, University of Chicago, 5841 S. Maryland, MC-2007, Chicago, IL 60637. Telephone: (773) 702-2453.
Michael Krieger, senior project manager, Spectrascan Health Services, 200 Day Hill Road, Windsor, CT 06095. Telephone: (860) 285-0545.
Barnett Kramer, MD, MPH, deputy director of the division of cancer prevention and control at the National Cancer Institute, 31 Center Drive, Bethesda, MD 20892. Telephone: (301) 496-9569.
Paul Engstrom, MD, senior vice president for population science at Fox Chase Cancer Center in Philadelphia. Telephone: (215) 728-2986.
Ivor Benjamin, MD, assistant professor, division of gynecologic oncology, department of obstetrics and gynecology, University of Pennsylvania Cancer Center in Philadelphia. Telephone: (215) 662-3316.]