More than a decade before Andrew von Eschenbach pledged to end the pain and suffering of cancer by 2015, the American Cancer Society set a more realistic goal of halving the U.S. cancer mortality rate by the same date.

A midpoint assessment of progress toward that goal appeared in the July issue of Cancer, the society’s journal. It told a classic glass half-full, half-empty story. The good news was that during the 1990s and this decade, cancer rates finally began falling by about 1 percent a year after decades of steadily creeping upward. The bad news was that the mortality rate needed to fall twice as fast to meet the Society’s ambitious goals

The stats revealed what every oncologist already knows — not all cancers are created equal. Breast and colorectal cancer mortality rates have dropped sharply over the past 15 years. And lung cancer rates for men have been falling steadily. But the rate for lung cancer among women, after rising during the 1990s, has merely stabilized more recently. Meanwhile, the cancer death rates for middle-aged Americans and Afro-Americans showed sharp declines. But there has only been middling progress for people over aged 65 and for Hispanics.

I spoke recently with Dr. Tim Byers of the University of Colorado Health Sciences Center in Denver, who led the team of epidemiologists that sifted the data for the Society. The big gains, he noted, have not come from better treatments, but from aggressive public health measures. At the top of the list was the war against smoking, which isn’t surprising since lung cancer accounts for more than 25 percent of all cancer cases. “If we can get the 25 percent of the population who still smokes to stop, it would go a long way to achieving the 2015 goal,” he said.

As he cast his eye over the other major cancer sites, he again saw the cancer world through a public health prism. Breast cancer mortality rates have been dropping by over 2 percent a year and are well on their way to meeting the 2015 goal of being cut in half from 1990. But recent trends suggesting overall incidence is finally declining may not hold. “Incidence may start creeping up again,” he said, “in part because of the obesity epidemic.”

Mortality rates for the other major cancers sites — colorectal and prostate — are also dropping quickly enough to meet the ACS goal. In the former case, it’s probably due to a mixture of earlier detection through better screening (50 percent of the population over 50 now gets regular colonoscopies) and the availability of fresh fruit year round.

And prostate cancer?

“Who knows?” said Byers. “The rate started coming down long before you could have expected any results from PSA (prostate specific antigen) screening. We don’t have clinical trial results in from screening or to show that a combination of screening and antiandrogen treatment has affected the death rate.”

But the most sobering data came from the 50 percent of cancers that affect the rest of the organs and sites of the body. There’s hardly been a dent in the mortality rates for pancreatic, renal, liver, or gastrointestinal cancers. “We either don’t know what causes them, or we haven’t figured out how to do screening for early detection, or we don’t know how to treat them,” Byers said. “We need a PSA equivalent for these sites.”

For leaders of the war on cancer, then, the roadmap should be clear: if the nation is going to double the rate of decline in cancer mortality rates, it needs to focus like a laser beam on two major initiatives. First, they need to step up public health measures for fighting the primary causes of cancer: smoking and obesity. Second, they need to focus more attention on developing better and cheaper tools for early detection.

Alas, here again, we find a glass half-full story. On the smoking and obesity fronts, the nation is, if anything, moving backwards.

“Despite the proven effectiveness of well funded tobacco-control programs, such programs have not been developed in all states, and some of the most effective programs have been cut in recent years because of state budget shortfalls,” the report in Cancer said. And despite public hand wringing about obesity, effective public health measures for reducing America’s collective waistlines have not yet been identified, much less supported with public resources.

On the screening front, however, the emerging world of proteomics and DNA screening holds out great promise. While officials at National Cancer Institute and the Food and Drug Administration are encouraging industry to come up with new tests based on these technologies, progress is slow. “We need to come up with a blood test that people could get every couple of years,” Byers said.

So whether it will be a blood test or a drop in obesity rates, the road to the Society’s ambitious 2015 goals is going to be a challenge no matter how you view the glass.

Merrill Goozner

Posted on October 1, 2006 06:00 AM