Cancer cases decline in U.S. Changes in lifestyle, rejection of tobacco credited for new trend

Drop is 1st since '30s

Death rates decline, but decrease in Md. is smaller than nation's

March 13, 1998|By Jonathan Bor | Jonathan Bor,SUN STAFF

The rate of new cancers among Americans has declined for the first time since the 1930s, a historic change that experts attribute largely to the nation's shift away from tobacco.

News of the downturn came yesterday in a "report card" from the American Cancer Society and government health agencies. The report confirmed a similar downturn in cancer death rates -- a trend reported two years ago on the basis of preliminary evidence.

With the good news came a warning: Higher rates of smoking among today's teen-agers will cause cancer rates to soar a generation from now unless teens kick the tobacco habit and younger children never start.

"What this says to me is that we can't be complacent about these encouraging results," said Dr. Phyllis Wingo, surveillance director at the American Cancer Society in Atlanta. "We've made strides in some areas, but we've got to keep doing what we're doing and do a better job of it."

Among the four leading cancers, rates of new lung, colon and prostate cancers declined while breast cancer leveled off.

Cancer remains the second leading cause of death in the United States, behind heart disease. Almost 1.4 million cases are diagnosed each year.

The report shows that the incidence of cancer peaked in 1992, then decreased by an average of 2.7 percent per year from 1992 to 1995. This means that at least 70,000 fewer people were diagnosed during those years than would have been if previous trends had continued.

The improvement wasn't enjoyed by all demographic groups. The cancer incidence among black men and Asian women inched upward during the period. Black men have the highest rates in the country, primarily because of an increase in prostate cancer. Black women also suffered higher rates of breast cancer.

Although the government has been monitoring cancer trends in detail only since the mid-1970s, the report said that cancer rates had been rising steadily since the 1930s.

Because of studies linking smoking to cancer, fewer than 25 percent of adults smoke today compared with 42 percent in 1965. That decline is finally bearing fruit: fewer cancer cases and deaths in the 1990s.

The decline in new cancers was somewhat slower in Maryland, where state authorities said yesterday the incidence had dropped 2.7 percent between 1992 and 1995. The improvement was seen across all four major cancers.

Cancer death rates also declined less significantly in Maryland, at a rate of less than 1 percent over the period. The state has the fifth-highest cancer mortality rate in the United States.

Still, state Health Secretary Martin P. Wasserman saw reason for optimism.

"This is an area where public health can take some credit," he said. "People are heeding public health messages. On the other hand, what's discouraging is that over a third of 12th-grade kids throughout the state are starting smoking.

"We, as a society, have to do much more than were are doing to make sure those children today are not the mortality statistics of tomorrow."

Among the findings, to be published in Sunday's issue of the journal Cancer:

Lung cancer incidence declined 1.1 percent per year from 1990 to 1995, due mainly to lower smoking rates. Lung cancer mortality also dropped, but only women of Hispanic origin shared in the overall decline. "The change in smoking behavior in females lagged behind males," said Wingo.

TC Breast cancer rates increased 1.8 percent per year from 1973 to 1990, but the rate was level from 1990 to 1995. Death rates declined slightly during the period. Experts tied the improvement to greater use of mammography, which can detect tumors before they spread.

After rising significantly from 1973 to 1990, the incidence of prostate cancer declined 1 percent per year from 1990 to 1995. Death rates declined at about the same rate. The PSA (prostate specific antigen) blood test caught thousands of early cancers when it was introduced in the late 1980s. With those men in treatment, experts are not surprised that fewer cases are being detected today.

"Colo-rectal cancer is tough -- we really don't know what's causing the downturn in incidence," Wingo said. Several things could explain it: the removal of precancerous polyps and the more widespread use of aspirin and estrogen, both of which are thought to protect people from the disease.

Dr. Martin D. Abeloff, director of the Johns Hopkins Oncology Center, said it was also hard to explain why fewer women overall are developing breast cancer. "One speculation is that perhaps we're beginning to see some changes in lifestyle and diet that are beginning to be played out," he said.

While women might be turning toward low-fat foods in hopes of preventing breast cancer, the link between dietary fat and breast cancer remains controversial, he said.

"In terms of mortality, what we're seeing is a combination of better detection methods and increased access and utilization of these methods," Abeloff said.

Abeloff said he was encouraged by the report, but not overwhelmed.

"I would call it an incremental advance rather than high drama," he said. "It's extremely important. It shows we're heading in the right direction."

Pub Date: 3/13/98

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