CHICAGO (Reuters) - Improvements in cancer screening and better treatments have resulted in steady declines in cancer death rates over the past three decades, U.S. researchers said on Thursday.

A cancer patient is seen through the tube of a magnetic resonance imaging scanner at Georgetown University Hospital in Washington May 23, 2007. REUTERS/Jim Bourg

They said younger adults -- those aged 35 to 45 years old -- have experienced the steepest declines in cancer death rates, but all age groups have shown some improvement.

“Essentially, the younger you are, the faster your rates are declining,” said Dr. Eric Kort of the Helen DeVos Children’s Hospital in Grand Rapids, Michigan, whose study appears in the journal Cancer Research.

The study uses a different way of looking at cancer death rates that measures improvements in cancer deaths by age.

U.S. government estimates suggest there had been little improvement in cancer death rates throughout the 20th century, with rates only beginning to improve in the mid-1990s, Kort said. But that does not tell the whole story, he said.

“The way that these statistics are traditionally reported is they have averaged all of the age groups together to get a composite rate,” Kort said in a telephone interview.

“The problem with that is because most cancer deaths occur in older Americans, the average heavily emphasizes the experiences of older people. It’s like watching the caboose of the train to tell when the train is changing direction,” he said.

Instead, Kort’s team looked at improvements in cancer deaths among groups of individuals born in five-year intervals starting in 1925.

Using that method, Kort said, “Everyone born since the 1930s has enjoyed a decreased risk of cancer death, at every age.”

People in the youngest age group -- those aged 35 to 45 -- had a greater than 25 percent decline per decade in cancer deaths, he said.

Kort said cancer prevention -- including smoking cessation efforts -- have played an important role in these trends.

“We’re also benefiting in profound ways from progress we’re making in early detection and better treatments. Some of these advances benefit younger people first,” he said.

In childhood cancers, advances in treatments for leukemia and lymphoma mean many more people can survive cancers that were once considered a death sentence.

And better screening for cancers that occur in older age, such as mammography in breast cancer and colonoscopy for colon cancer are spotting cancers at an earlier stage, when they are easier to treat.

Cancer remains the No. 2 killer of Americans, with about 560,000 deaths annually, topped only by heart disease, according to the American Cancer Society.