A new report says that, for the first time in 40 years, fewer women are dying from lung cancer. That's great news, but it doesn't mean women can take a deep breath, sit back, and relax about efforts to prevent lung cancer.

Even with the drop in death rates, lung cancer is still the frontrunner among cancer deaths for both men and women by a wide margin, says Barbara Campling, MD, a lung cancer specialist at Thomas Jefferson University Hospital in Philadelphia.

Here's what women need to know about their risk and how to prevent lung cancer.

Lung Cancer: Rates Among Women Are Going Down

The Journal of the National Cancer Institute recently released an annual report that noted a significant drop in both lung cancer rates and lung cancer deaths among women between 2003 and 2007 and that lung cancer rates in women are expected to continue to drop for at least the next 20 years.

However, the drop in rates among women is happening more than 10 years after men's rates dropped, the researchers said. That's because the biggest lung cancer cause is smoking. Lung cancer rates and mortality have very closely followed rates of cigarette smoking, Dr. Campling says. And men started smoking earlier than women.

Smoking peaked in men during World War II, when cigarettes were considered to be essential military supplies. Afterward, lung cancer rates for men went way up and then started coming down more than 10 years ago.

Women, on the other hand, didn't take up smoking until about 10 years after men did, when tobacco companies began aggressively marketing to them. Cigarette companies told women to reach for a smoke instead of a sweet to get a slender figure, Campling says.

As women started smoking later than men, they also started reducing their tobacco consumption later, she says.

Lung Cancer: Women's Risk of Cancer Is Still High

More women still die from lung cancer than any other type of cancer. In 2007, more than 93,000 women in the United States were diagnosed with lung cancer and more than 70,000 died from it.

Smoking is by far the primary lung cancer cause. It causes 80 to 90 percent of cases, which means quitting is the key to lowering your risk of cancer.

"Everybody who smokes should stop," Campling says. "Everyone who hasn't started should never start."

People who quit smoking will remain at higher risk for lung cancer for years, but that risk will go down over time. For that reason, if you've been a heavy smoker, your doctor should follow you closely for signs of lung cancer even after you quit, Campling says.

And there's something else you can do if you've been a smoker: Get screened. Screening means looking for lung cancer even though you have no symptoms of it. Preliminary data is showing that screening may reduce mortality rates, explains Campling.

Doctors don't routinely do screenings, but it's something you can request. Screening involves getting a low-dose spiral CT scan, which gets a good look at the lung tissue, says Campling.

Following this advice will help significantly to prevent lung cancer.