President Nixon declared war on cancer in 1971 and, since then, the National Cancer Institute (part of the NIH) has funded research on prevention, surveillance, and treatments. But, despite the effort, progress has been elusive, leading to press reports in Newsweek, Fortune, and The New York Times suggesting that, at best, cancer is fighting us to a draw. But a new analysis of death rates, performed by staff at the American Cancer Society, indicates that cancer death rates peaked around 1990, and have been declining broadly since. As a result, they're now below where they started in 1970.
The dynamics in many specific populations are quite distinct. Relative to women, men started out with a higher age-standardized death rate, saw a more rapid increase, peaked a year earlier, and then have seen a far more dramatic decline. Various ethnic groups also had different trajectories, but all have shown declines in recent years. The trends have been more dramatic in younger populations as well.
The changes also vary based on cancer types. "The 2006 death rates for Hodgkin lymphoma in men, cervical cancer in women, and stomach cancer in both men and women were less than one-third of the 1970 rates," the authors conclude. In contrast, liver cancer death rates are increasing, as are pancreatic cancers in women, and melanoma and esophageal cancer in women. But, for 15 of the 19 cancers studied, rates have dropped.
The biggest factor in the change, according to the authors, is prevention: people are smoking less, and we should see continued improvements in this regard due to the decreased rates of smoking in adolescents. Mammograms, the Pap smear, and increased colonoscopy rates all account for drops in their relevant cancers, indicating that detection is also playing a role, while new treatments had impacts in lymphomas, leukemias, and testicular cancer.
There are a couple of take-home messages here. For one, we tend to expect success in the war on cancer to come in terms of treatments, but prevention and early detection are having a far more significant effect. But they take much longer; the oldest generations are missing out on the drop in smoking because the time-lags are so long. Finally, there's some indication that the rise in a few cancers may be tied to increased obesity, however, so there's no guarantee of continued success.