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Heavy smokers urged to have CT scans for lung cancer

January 9th, 2014

By Deborah Kotz for the Boston Globe

Many heavy smokers and smokers who recently quit should be screened annually for lung cancer with a computed tomography scan that uses a low dose of radiation, a national panel of prevention experts said Monday.

Some of these people now get routine chest X-rays, but the panel concluded that CT scans are better able to detect the tiniest lung cancers at an early, more curable stage.

Current cigarette smokers ages 55 to 80 who have smoked the equivalent of a pack a day for 30 years, or people who had those same smoking habits within the past 15 years, should be screened, advised the US Preventive Services Task Force, a group created by Congress. Under the federal health law, insurance companies will have to begin covering the $300 to $400 cost of the screening by the end of 2014.

“The medical community is pretty much in lock step on this recommendation,” said Dr. Otis Brawley, chief medical officer of the American Cancer Society, which issued similar advice last year. “Lives will be saved,” he added, though community radiology centers need to ensure that they have the appropriate machines and competent medical staff administering and reading the scans.

About 85 percent of lung cancers occur in smokers, and nearly 90 percent of people who get the malignancy die of their disease. The high fatality rate explains why this relatively uncommon cancer accounts for 160,000 deaths in the United States each year — more than breast, prostate, and colon cancers combined.

The task force calculated that 14 percent of these lung cancer deaths could be prevented if everyone who was eligible had an annual screening, saving a potential 22,400 lives each year, according to the recommendation published Monday in the Annals of Internal Medicine.

“For non-smokers and those who haven’t smoked for 15 years, the evidence suggests that the harms of screening outweigh the benefits,” said Dr. Michael LeFevre, co-vice chair of the task force and a professor of family and community medicine at the University of Missouri School of Medicine.

Such harms include a high rate of abnormal findings, which turn out not to be cancer but often necessitate follow-up tests such as high-dose CT scans — with 10 times the radiation dose of the screening scan — and, less commonly, lung biopsies. “When a patient gets a phone call saying a CT scan isn’t normal, 19 out of every 20 times it’s not cancer,” LeFevre said.

In a large clinical trial of more than 50,000 smokers on which the task force’s recommendation was based, CT screening clearly trumped chest X-rays. Those who were randomly selected to have CT screening three times over two years had a 20 percent lower risk of dying from lung cancer compared with people who were randomly picked to get chest X-rays.

But 27 percent of the participants who were screened with CT wound up with an abnormal finding, which often required follow-up screening with another low-dose scan. Some needed a high-dose diagnostic scan before learning their abnormal finding was benign; 7 percent of people who initially had abnormal scans wound up having lung surgery to remove a tissue sample for biopsy, but only 4 percent of those with abnormal scans actually had cancer.

The task force calculated that the cumulative radiation dose from CT scans would cause 24 radiation-induced lung cancer deaths for every 100,000 smokers who followed the screening recommendations; 521 lung cancer deaths, however, would be prevented due to early detection of smoking-related tumors.

Primary care physicians should provide smoking-cessation counseling to lifelong heavy smokers along with a CT-scan referral, the task force said, and it also emphasized the importance of setting up a national registry to track the real-world use of CT screening in order to determine whether doctors are able to achieve the same rate of cancer diagnoses seen in the ideal setting of a clinical trial and minimize the number of biopsies performed.

But that still “does not address many practical aspects of implementing lung cancer screening,” wrote Yale University thoracic surgeon Dr. Frank Detterbeck and his colleague in an editorial that accompanied the new recommendation, such as “individuals who have great anxiety about developing lung cancer even though their risk is actually not so high,” leading them to seek screening though it is not recommended for them.

“We worry how this technology will translate when it moves from 33 of America’s best hospitals that were involved in the clinical trial to community hospitals across the country,” Brawley said.

Lahey Hospital and Medical Center in Burlington has performed free lung CT screening in more than 1,700 patients over the past two years, screening only individuals who meet strict criteria for being at high risk of lung cancer that are similar to the task force recommendations. Even after extensively educating primary care physicians who write the referrals, however, Lahey radiologists still turn away about 10 percent of patients for screening because they don’t qualify as high risk, according to Dr. Andrea McKee, chair of radiation oncology at Lahey.

The American College of Radiology, which represents the nation’s radiologists, said in a statement that it supports the new recommendations and is working “to complete practice guidelines that cover how lung cancer screening CT exams are performed, interpreted, and results communicated” — similar to standards in place for mammography centers.

But, Brawley pointed out, there was “a 20-year learning curve with mammography, and we still have problems with radiologists not correctly interpreting the scans.”

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