The West is leading a national decline in the rate of new lung cancer cases, with states like California and Nevada accounting for much of the improvement, particularly among women.
Smoking rates in the West have long been lower, and that's credited for the good health news for that region. Roughly 90 percent of lung cancer cases are attributed to smoking.
Lung cancer rates for men have been declining for years, but the drop among women is much more recent. The Centers for Disease Control and Prevention reported Thursday that lung cancer rates for women nationally decreased about 2 percent from 2006 to 2008, the last year studied. But the rate for women in select Western states fell about 4 percent in the same period.
Declines among men were similar, including a 4 percent decline in the West and about a 3 percent drop nationally.
"Over the past 20 years, lung cancer overtook breast cancer and became the No. 1 cancer killer of women. This is a horrific development that we have begun to turn around," said Dr. Tim McAfee, director of the CDC's Office on Smoking and Health.
Female lung cancer rates did not decline in every state, but six states saw significant drops - California, Nevada, Oregon, Washington, Texas and Florida. That was enough to pull down the national rate, even though female cancer incidence rose slightly in 14 states.
The rate of new lung cancer cases among males dropped in 35 states.
Lung cancer was something of a medical rarity 100 years ago, but is now one of the most commonly diagnosed cancers in the United States and is the form of cancer that kills the most people. More than 150,000 Americans will die of it this year, the American Cancer Society estimates.
It can take many years for lung cancer to develop in a smoker, although lung cancer rates can be seen to drop as soon as five years after smoking rates decline.
In the new report, CDC researchers looked at national cancer registries for the years 1999 through 2008, and also studied state-specific smoking rates from a separate data base that covered the same time period. The results are being published this week in a CDC publication, Morbidity and Mortality Weekly Report.
The CDC report didn't capture all 50 states. Six were left out because the authors were not able to say what was going on with lung cancer rates in those states for the earlier years of the analysis. Five of those states are in the South, where smoking rates and cancer rates tend to be high.
A stark regional difference was seen in 13 Western states. Texas, grouped in with the South by the researchers, also saw significant declines. The regional declines in male lung cancer incidence were similar for men.
Smoking rates are lower in the West. The national smoking rate has hovered around 20 percent for several years, but the rates have been below - in some cases, well below - 19 percent in California, Hawaii, Oregon, Washington, Idaho, Montana, Utah and Arizona.
Health officials and some advocates say at least some of the difference is due to some states having higher taxes on cigarettes, more comprehensive smoking bans and well-funded prevention programs. California is considered the prime success story for such health policies.
"Many Americans have a greater risk of lung cancer because of where they live and because their elected leaders have failed to implement proven measures to reduce tobacco use," said Matthew Myers, president of the Washington, D.C.-based Campaign for Tobacco-Free Kids.