The federal government will pay for annual CT scans to screen for lung cancer among Medicare patients between the ages of 55 and 77 who are or were long-term smokers, the Centers for Medicare and Medicaid Services (CMS) announced late Thursday.

Lung cancer, which kills more than 150,000 Americans each year, is the deadliest cancer in the country. Roughly 85 percent of all lung cancers are attributed to smoking.

When the cancer is detected early, most patients with non-small cell cancer survive at least five years. Those with small cell lung cancer, who are nearly all smokers, have a poor prognosis no matter what.

But when the cancer is caught early, patients survive 16 to 24 months on average, compared to six months to a year when the disease is more advanced, according to the National Cancer Institute.

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“This is the first time that Medicare has covered lung cancer screening. This is an important new Medicare preventive benefit since lung cancer is the third most common cancer and the leading cause of cancer deaths in the United States,” said Dr. Patrick Conway, chief medical officer and deputy administrator for innovation and quality at CMS.

Most private insurers already pay for lung-cancer screening programs and the federal agency’s decision to include the coverage for its 43 million beneficiaries came in response to input from doctors and patient advocacy groups, including the American Cancer Society (ACS).

The ACS will work with medical groups to expand the number of CT screening centers “so that high quality lung cancer screening is available to everyone who meets screening criteria,” according to a statement from Dr. Richard Wender, the group’s chief cancer control officer.

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CT scans, or low-dose computer-assisted tomography scans, are costly, but they are the most reliable way to catch lung cancers in their earliest stages.

To qualify for screening, Medicare beneficiaries must be current smokers or have quit within the past 15 years. They must have a smoking history of at least 30 “pack years,” or an average of one pack a day for 30 years.

The benefit is available immediately. Patients who are active smokers are also covered for smoking cessation support.

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