TUESDAY, Sept. 2, 2003 (HealthDayNews) -- A steady decrease in national cancer cases and deaths that started in 1992 leveled off toward the end of the decade, says the government's annual report on the status of cancer.
The fact that death rates for women did not decline in the late 1990s, while there was only a slight decline in male death rates, shows that "much still needs to be done to reach the Healthy People 2010 goals, including wider application of what science has shown to be effective in preventing, screening and treating cancer," says a statement by Dr. Julie L. Gerberding, director of the U.S. Centers for Disease Control and Prevention, one of the agencies that prepared the report. It appears in the Sept. 3 issue of the Journal of the National Cancer Institute.
But "the positive side is that we continue to see declines in some of the major cancers," says Brenda K. Edwards, associate director of the National Cancer Institute's surveillance program. "We're seeing declines in the four most common cancers -- lung, breast, prostate and colorectal."
For both breast and prostate cancer, there have been steady declines in death rates, while the incidence of diagnosed cases continues to rise. Improvements in diagnostic techniques led to an increased report of incidence, Edwards says, "which leads to early treatment and improves overall outcome. Many years later, you will see a reduction in death rates."
The decrease in breast cancer deaths has been attributed to increased use of mammography screening, and the prostate mortality decrease is sometimes attributed to PSA -- prostate specific antigen, a marker for the disease -- screening. But there still are debates about the value of PSA screening, Edwards says.
"There are questions about possible over-diagnosis and over-treatment in early stage disease that may not have gone on to become clinically evident," she says.
One important factor in the overall picture is that "we have a growing and aging population," Edwards says. Since cancer incidence increases with age, "we are seeing an increase in the number of individuals who are diagnosed and treated," she says. "With more effective treatment, we have a growing number of individuals alive today who have had cancer in the past."
For lung cancer, the leading cause of cancer deaths in the United States, the mortality rate for men dropped throughout the decade because of a decrease in cigarette smoking. Lung cancer deaths among women have continued to rise, but at a slower rate.
For colorectal cancer, the second leading cause of death, incidence rates have been stable since 1996, while the death rate continues to drop. But the decrease has been greater among whites than for blacks, the report says, "an indication that black men and women may not have experienced the same benefit from screening and treatment as white men and women."
The best thing about the report, says Holly L. Howe, executive director of the National American Association of Central Cancer Registries organization, is that it is more complete than ever before. The report include incidence data from 34 state registries that cover 68 percent of the nation's population. Earlier reports covered only 55 percent of Americans.
"For the last couple of years, registries that had been outside the report have been able to be included, so that we are moving forward to produce more accurate incidence data," Howe says. "We have data that will help those states better plan and evaluate cancer control programs. The better data we have, the more we can improve those programs."
"We are extraordinarily pleased that we now have a registry that includes 68 percent of the American people.," Howe says.