The number of Americans diagnosed annually with cancer will double over the next 50 years, from 1.3 million to 2.6 million, according to the study, which warns of an increased burden on the health care system.
The expected boom reflects a population that will be larger and live longer — rather than suggesting that cancer itself will become more menacing. In fact, the report said the death rate from cancer in the United States fell an average of more than 1 percent per year from 1993 to 1999.
One big exception was lung cancer death rates in women - which mirror the rise of the popularity of smoking among women. Cancer experts say smoking causes 90 percent of lung cancer cases, and lung cancer is the biggest cancer killer in the world.
The four major killer cancers — lung, colorectal, breast and prostate — accounted for 53 percent of all cancer deaths in the United States from 1995 to 1999, the study found.
Death rates are down because better treatments mean people live longer with cancer, screening catches many cancers earlier, when they are more treatable, and fewer people are smoking, the report said.
Researchers analyzed census data and applied it to newly compiled cancer statistics to make the projections, which appear Wednesday in the journal Cancer.
The increase in older cancer patients will require more cancer specialists who can treat them, the study warns. There are already shortages in many of those professions.
The figures "underscore a critical need for expanded and coordinated cancer control efforts to serve an aging population and reduce the burden of cancer in the elderly," said Dr. Richard Hodes, director of the National Institute on Aging.
"As we get older, those rates go up quite a bit," Brenda Edwards of the National Cancer Institute told CBS News on Monday.
The study is the result of analysis by the National Cancer Institute, the American Cancer Society, the Centers for Disease Control and Prevention and the North American Association of Central Cancer Registries.
While cancer death rates slowly dropped, the rate of cancer cases overall stabilized in the 1990s after rising in the 1970s and 1980s, the report found.
Using new statistical analysis, the researchers estimated 8.9 million people were living with cancer in the United States at the beginning of 1999. About 60 percent of those were 65 or older.