The report offers detailed statistics on deaths and new cases for all cancers. The data covers the period 1975 to 2005.
Cancer deaths have been dropping since the early 1990s, but dropped faster in the most recent time period, 2002-2005.
"This is real progress," says the report's lead author, Ahmedin Jemal, PhD, strategic director for cancer surveillance at the American Cancer Society. "It's the result of improvements in early detection and treatment."
Harder to interpret is the overall decline in new cases of cancer.
"It is encouraging, but not as rock solid an indicator of true improvements as mortality," National Cancer Institute epidemiologist Barry Miller, DrPH, tells WebMD.
That's because factors such as cancer screening affect the number of new cases. Increased screening would catch more cancers, but would also catch indolent cancers that might go away on their own if undetected.
Changes in cancer risk factors also affect the number of new cancer cases, Jemal notes. He offers the decline in new cases of breast cancer as an example.
"Is that due to decreases in the number of women on hormone replacement therapy? That would be a good thing. Or is it due to the decrease we've seen in the number of women getting regular mammograms? Maybe we are not detecting as many breast cancers at an early stage, and that is not good news," Jemal says.
Some Cancers Down, Other Cancers Up
Most of the decline in cancer deaths and new cancer cases can be attributed to:
- Declines in the three most common cancers in men: lung cancer, colon cancer, and prostate cancer
- Declines in two of the three most common cancers in women: breast cancer and colon cancer
- Leveling off of cancer death rates of the second most common cancer in women: lung cancer
For several cancers, new cases increased from 1990 to 2005:
These increases, however, likely are a result of increased detection with improved imaging technology -- so the increases may mostly be early, less lethal cancers.
One cancer, however, dominates the statistics: lung cancer in American smokers. Even with the dramatic decrease in smoking seen in the last decade, cigarette smokers account for nearly a third of all U.S. cancer deaths.
Although lung cancers are down overall, there are huge regional variations. The decline in lung cancer deaths in men, for example, was twice as large in California as in many Midwestern and Southern states.
Among women, lung cancer deaths actually increased in 13 states -- all in the South and Midwest. In these states, there are relatively fewer tobacco control programs, lower taxes on cigarettes, and less tobacco-lawsuit settlement money going to anti-smoking efforts than in other states.
"This report highlights a success story in that it correlates declines in lung cancer deaths with incentives to get people to stop smoking or not take up smoking," Miller says. "We need to redouble efforts to impact populations across the country and make an impact where we haven't before."
"States can get huge dividends from promoting tobacco control programs, but it is always on the back burner," Jemal says. "States got $25 billion from the tobacco settlement, but only 3% goes to tobacco control efforts. And any time state officials have a budget shortfall, the first cut they think of is tobacco control efforts."
Still Too Many Cancer Deaths
Offsetting the good news that U.S. cancer deaths are down is the knowledge that the nation could have done even better.
"This progress could have been accelerated even more by ensuring that all populations in America have timely access to health care and prevention measures," Jemal says. "We know that almost 47 million Americans are uninsured, and there are 25 million more underinsured -- not to mention the underserved populations, such as American Indians. So we are not delivering what we know about cancer interventions to all segments of the population."
A change in focus also is needed. Jemal says that the current system focuses on cancer treatment but fails to give enough attention to cancer prevention.
"We need more emphasis on promotion of well-being such as getting more physical activity, achieving a healthy body weight, and eating a healthy diet," he says. "And the 44 million U.S. adults who smoke really need help to quit but are not getting that help. Nearly half of smokers try to quit, but only 20% get needed help from their doctors."
Although new screening tests are needed, existing cancer screening tests are underused. The main example here is colon cancer, which can be detected when about 90% of cases are curable -- yet only half of adults aged 50 and older get the recommended colon cancer screening.
And, Jemal says, more money is needed for research. The declines in cancer deaths we see today are a direct result of past investments in research.
"When you talk about investments in cancer over the last 5-7 years , it has been flat. We have to make cancer a priority," Jemal says.
The American Cancer Society's annual report appears in the Dec. 3 issue of the Journal of the National Cancer Institute.