News from the cancer front: time to shift emphasis from treatment to prevention
May 29, 1997
Despite 25 years of intense research and thousands of clinical trials of promising new cancer therapies, there has been only scattered progress in treatment since President Richard Nixon declared the "War on Cancer" in December 1971, report two researchers from the University of Chicago in a Special Article in the May 29, 1997 issue of the New England Journal of Medicine.
In an earlier assessment, published in 1986, John C. Bailar III, MD, PhD, then at Harvard University, declared that "years of intense effort focused largely on improving treatment must be judged a qualified failure."
In 1997, with 12 more years of data and experience, "we see little reason to change that conclusion," reports Bailar, now professor and chair of health studies at the University of Chicago.
"However one analyzes and interprets the present data," wrote Bailar and co- author, medical student Heather Gornik, "the salient fact remains that age-adjusted rates of death due to cancer are now barely declining. Hopes for a substantial reduction in mortality by the year 2000 were clearly misplaced." The authors recommend shifting much of the research emphasis away from treatment and toward prevention and early detection.
Their report, though hardly optimistic, includes a silver lining. It confirms, using more rigorous statistical techniques than two earlier reports, that the steady increase in age-adjusted mortality for all cancers plateaued around 1991 followed by a 1 percent decrease, from 203.0 to 200.9 per 100,000, from 1991 to 1994. Two earlier reports found the same decline in mortality but overstated its extent.
Most of the decline, however, can be traced not to improved treatments but to reduced cigarette smoking, improved screening and decreases in the incidence of certain types of cancer.
There has been significant progress in treatment of certain cancers, the researchers acknowledge. Death rates for each major category of childhood cancer, for example, decreased by about half since 1970 and continue to drop, but since fewer than one-third of 1 percent of cancer deaths occur in children younger than age 15, even the complete elimination of childhood cancer deaths would have little impact on overall cancer mortality.
Other advances include better treatment for specific cancers such as Hodgkin's disease and testicular cancer, much better pain control, growing knowledge of the virology and of the biochemistry of cancer--knowledge that has improved treatment for many other diseases including AIDS--and considerable progress in medical imaging.
There is also considerable optimism about new modes of treatment, such as gene therapy, that are emerging from a better understanding of the molecular mechanisms of cancer.
But the arguments in favor of these promising new forms of therapy "are similar in tone and rhetoric to those of decades past about chemotherapy, tumor virology, immunotherapy and other approaches," the authors note. "Prudence requires a skeptical view."
"Since the slight decrease in cancer mortality largely reflects changing incidence or earlier detection, rather than improved therapy, the logical next step, we believe, would be to shift more resources into an arena where we have proved that they make a difference and concentrate our efforts on prevention and early detection of cancer," says Bailar.
Redirecting resources to cancer prevention will not be simple. "Prevention is likely to be more difficult and costly than treatment," warn the authors, citing the prolonged and difficult struggles to reduce tobacco use or improve diets. It will require both better understanding of the roles of nutrition, of preventive supplements and inherited risk as well as vastly improved methods of persuading the general public to alter their lifestyles, habits and diets.
Despite the enormous difficulties of changing basic behaviors such as smoking, diet or exercise habits ,"a national commitment to the prevention of cancer, largely replacing reliance on hopes for universal cures," exhort the authors, "is now the way to go."
Because there has been only scattered progress in treatment since the "War on Cancer" was declared in December 1971, researchers from the University of Chicago recommend, in a New England Journal Special Article, shifting much of the research emphasis away from treatment and toward prevention and early detection.
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