WASHINGTON — Screening smokers and ex-smokers with high-tech CT scans has been shown for the first time to significantly cut deaths from lung cancer, the leading cancer killer, federal health officials announced Thursday.
A long-awaited study of more than 53,000 middle-aged and elderly people who either once smoked or currently smoke heavily found there were 20 percent fewer deaths among those who underwent annual screening with a scanning procedure known as low-dose helical computed tomography compared with those who got standard chest X-rays.
The findings were so striking that the National Cancer Institute, which sponsored the study, halted the National Lung Screening Trial early so the public and participants could be alerted.
"This finding has important implications for public health with the potential to save many lives among those at greatest risk for lung cancer," said NCI Director Harold Varmus. "This finding will be an important factor in subsequent efforts to protect the tens of millions of former and current smokers in this country against the lethality of lung cancer."
Lung cancer strikes more than 196,000 Americans each year and kills more than 159,000 — more than breast, colorectal, pancreatic and prostate cancers combined. Although significant advances have been made in reducing deaths from other leading cancers, lung cancer has remain stubbornly resistant and most victims die. The new finding marks the first good news about the disease in decades. There are an estimated 91.5 million current and former smokers in the United States, all of whom are at increased risk for lung cancer.
CT scans, which create a three-dimensional image of the lungs instead of a one-dimensional perspective captured by standard chest X-rays, can spot more tumors when they are smaller and can be more successfully removed through surgery, boosting the chances of survival.
The findings were hailed by the American Cancer Society, American Lung Association, and others.
"With this positive trial result we have the opportunity to realize the greatest single reduction of cancer mortality in the history of the war on cancer," said James Mulshine, of Rush University Medical Center, in a statement issued by the Lung Cancer Alliance.
Even though CT scans can be performed by most hospitals, experts stressed that it was too soon to issue any specific recommendations about the use of CT screening for lung cancer. More analysis was needed to identify exactly who might benefit, such as those who smoked less heavily, and how often they should be screened, they said. Some expressed concern that the findings may lead to too many people undergoing unnecessary screening. The scans found abnormalities in about 25 percent of those screened, but most turned out to be a false alarm.
"As with any study of screening, there are also potential harms to be considered, such as potential overdiagnosis and needless surgeries," said Otis Brawley, the American Cancer Society's chief medical officer. "We have learned from the long-term analysis of other screening tests, such as mammography, that it is important to consider both benefit and harms associated with the test."
Others expressed concern about doctors exaggerating the benefits. The findings come as health experts increasingly have been challenging the value of screening for a variety of health problems. In recent years, experts have questioned whether mammography for breast cancer, PSA testing for prostate cancer and Pap smears for cervical cancer were being overused, subjecting too many patients to needless tests and treatment.
"Will the public-health community be able to manage the immediate consequences of this result, and ensure that there is a carefully planned rollout of screening to those individuals who will likely benefit, and with screening offered in places where follow-up care is available?" Peter Bach, of Memorial Sloan-Kettering Cancer Center in New York wrote in an e-mail. "Or will we see an avalanche of entrepreneurial radiologists taking out full-page ads and billboards tomorrow overstating the magnitude of the benefit, and without any plan in place for how to handle whatever is found or how to select the right patients for screening?"