CHICAGO - Lung cancer death rates among women in the United States fell for the first time in four decades, trailing a similar decline in men that started a decade ago, US cancer experts said on Thursday.

The lag reflects smoking trends among women, whose rate of smoking peaked later in the last century than US men, according to an annual report on cancer by the National Cancer Institute, the American Cancer Society and others.

"I think it's about time," Dr. Edward Kim of the University of Texas MD Anderson Cancer Center, who was not involved with the report, said in a telephone interview.

"When you look at the data, for years the biggest concern has always been the mortality rate for women with lung cancer. That number had just kept steadily increasing," Kim said.

"I think it is a reflection that finally we are beginning to make a bit of headway," Kim said.

Lung cancer deaths among women fell about 1 percent per year between 2003 and 2007, reflecting an overall continued decline in cancer rates and deaths, a trend that began in early 1990s as early detection and better prevention and treatments have helped more people survive their cancers.

"The observed decreases in overall cancer incidence and death in nearly all racial and ethnic groups are highly encouraging," researchers wrote in the report, which was also conducted by the North American Association of Central Cancer Registries and the Centers for Disease Control and Prevention.

New cancer diagnoses among both men and women fell about 1 percent a year between 2003 and 2007, and death rates fell an average 1.6 percent a year during the same period.

But the rate of decline will likely be overshadowed by the growing numbers of people in the United States who are over age 65, a group that is expected to reach 71 million people in 2030, twice the number reported in the 2000 census. Elderly people are more susceptible to cancer.

AGING POPULATION

"Even with declining cancer incidence rates, the absolute number of individuals diagnosed with cancer will continue to increase because of these populations," the researchers said.

That will lead to higher demand for cancer care, they said.

Among men, new cases of liver, kidney and pancreatic cancer and melanoma rose between 2003 and 2007, and rates of death for three of these cancers -- liver and pancreatic cancer and melanoma -- also rose.

In women, new cases of melanoma, leukemia, kidney, thyroid and pancreatic cancer rose in the 2003-2007 period, while cancer deaths in women rose among those with pancreatic and liver cancer. More women also died from uterine cancer in the 2003-2007 period, after falling from 1975 through 1997.

Cancer death rates in children continued a decline that started in the 1970s, but between 1992 and 2007, there was a slight uptick -- about 0.6 percent a year -- in the number of new cancer cases in children.

Black men and women had the highest death rates overall but also the largest declines in death rates from 1998 through 2007. For new cancers, black men and white women had the highest overall number of new cases.

The report dovetails with one released earlier this month that found nearly 12 million people in the United States are cancer survivors, almost four times as many as 40 years ago, reflecting big strides in cancer detection and treatment and the effect of an aging US population.

The American Cancer Society estimates there were 1.5 million new cancer cases in the United States in 2010 and 569,490 deaths. (Editing by Eric Beech)