The National Cancer Institute reported yesterday that lung cancer rates have dropped significantly among white men for the first time in more than half a century.
The drop -- 4 percent between 1982 and 1983 -- was attributed to a dramatic reduction in smoking that began two decades ago when a landmark 1964 surgeon general's report declared that cigarette smoking was the major cause of lung cancer.
NCI estimated that the drop translated to 3,300 fewer cases in 1983, down to about 80,000 cases in white men of the 135,000 new lung cancer cases diagnosed that year.
"This proves that people can successfully reduce their cancer risk by quitting smoking or not taking up smoking," said NCI's director, Dr. Vincent T. DeVita Jr. "It shows you can prevent even the most lethal of cancers. It's a very exciting piece of information."
But, he emphasized, the lung cancer news is not so promising among other groups. Increases in lung cancer continue for women of all races as well as black men. Among these two groups, smoking has not declined as rapidly as among white men.
"This year lung cancer is expected to top breast cancer as the leading cause of cancer deaths among women, and this has already happened in at least 15 states," DeVita said. In addition, he said that for black men "the annual rate of occurrence for new cases of lung cancer is almost 60 percent higher than for white men, although it appears to be leveling off."
Historically, since at least the 1930s, annual rates of new lung cancer cases in the United States increased up to 10 percent. But, in the mid-1970s, the rate of increase among white men began to slow, with changes most dramatic in men under age 45. From 1978 through 1982 the increase slowed to less than 1 percent annually.
As reported yesterday, however, in 1983 the rate among white men dropped significantly for the first time, declining from 82.7 new cases of lung cancer per 100,000 white men in 1982 to 79.3 in 1983. NCI said that the lung cancer death rate for white men has leveled off for several years but not yet shown a similiar decrease. A drop in new cases would be expected to precede a drop in mortality.
Dr. Edward Sondik, who reported the latest data to the NCI's advisory board as part of the annual cancer statistics review, said he had expected a drop in new cases but was surprised at the magnitude. He said in an interview that is "without doubt a payoff from the decline in smoking. It clearly heralds the start of a trend down."
He noted that changes in lung cancer cases paralleled smoking patterns over the past 20 years, with more men giving up smoking but little dropoff among women. For example, in 1965, 52 percent of adult males smoked cigarettes, falling to 38 percent in l980 and 35 percent in 1983. There were differences by race, however, with nearly 45 percent of black men smoking in 1980, compared with 37 percent for white men, he said.
Sondik said government studies showed that over 34 percent of American women smoked in 1965, 30 percent in 1980 and basically the same in 1983. NCI said that the lung cancer rate among women is still one-third that of men, but that women are catching up. Over the past decade both new case and death rates for lung cancer increased among women by about 6 percent annually.
In 1985, lung cancer, the leading cancer killer in this country, will kill about 125,600 Americans, including 87,000 men and 38,600 women. Over three-fourths of lung cancers are attributed to smoking. There is generally a lag time of more than a decade between exposure to cancer-causing agents and development of cancer. But once lung cancer is diagnosed, the prognosis is grim. Only about 13 percent of lung cancer patients are alive at the end of five years, only a 1 percent improvement over a decade ago.
The new NCI statistics show that for all cancers the incidence and death rates have increased over the past decade, incidence by more than 6 percent and mortality by 4 percent. Both DeVita and Sondik said, however, that lung cancer was largely responsible and masked treatment improvements in other cancers, including Hodgkin's disease, testicular cancer and childhood cancer tumors.
NCI said that between the mid-1970s and the early 1980s five-year survival rates for all cancer patients rose by 1 percent, to 49 percent. This means that nearly half were alive five years after diagnosis.
This includes a wide-range of survival odds for particular types of cancer. The latest five-year survival trends are highest for testicular cancer (88 percent) and cancer of the uterus (84 percent). Breast cancer remained level at 74 percent. Colon cancer survival was 53 percent.
The poorest prognosis is for cancer of the pancreas, which dropped to 2 percent of patients alive five years after diagnosis.