On Wednesday, a Medicare advisory panel voted unanimously not to recommend CT lung cancer screening coverage for high-risk individuals. They agreed that there was not enough evidence to determine if the benefits of low-dose CT lung screening (LDCT) outweighed the harms.

The decision by the panel, called the Medicare Evidence Development & Coverage Advisory Committee (MEDCAC), could represent a setback in efforts to gain national Medicare coverage for LDCT. The Centers for Medicare and Medicaid Services relies on the advice from MEDCAC to inform its coverage decisions.

Based on results from the National Lung Screening Trail (NLST), the U.S. Preventive Services Task Force recommended the screening for high-risk individuals in late 2013. NLST showed for the first time that LDCT screening can save lives when performed in the context of careful patient selection and follow-up. The USPSTF recommended in favor of annual LDCT screening for adults aged 55-80 years who have a 30 pack/year smoking history — meaning one pack a day for 30 years or the number of packs of cigarettes smoked per day by the number of years the person has smoked.

Normally, a recommendation by the USPSTF is seen as a potential win for Medicare coverage — but not necessarily in this case.

Dr. Steven Woolf, a professor in the department of family medicine and population health at Virginia Commonwealth University and a former member of the USPSTF, said he didn't think the USPSTF would have given a grade B recommendation for LDCT screening back when he was involved.

"In context, other major screening cancer trails have been result of multiple trials — we've never relied on one single trial," said Woolf.

The Affordable Care Act states that the USPSTF grade B recommendation guarantees that private insurers must cover LDCT without requiring a copay, but it does not extend that coverage to Medicare recipients.

While many of the panelists praised the NLST results, they expressed concerns about the potential harms of LDCT, including cumulative radiation dose from CT scans.

"Weighing risks and benefits in this study is really hard," said Dr. Harry Burke, a primary care provider at Walter Reed National Military Medical Center.

Since it's an older population, panelists also expressed concern about the harms and complications of interventions, like surgery, that could result if something suspicious showed up on the exam.

"Surgical mortality does increase as one gets older," said Dr. Rita Redberg, MEDCAC chair and professor of medicine at UCSF School of Medicine.

She added that there wasn't enough data on the total Medicare population, including those ages 75-80. NLST only analyzed data from smokers aged 55-74.

"A chest tube in an 80-year-old is a different story," said Dr. Mark Grant from the Center for Clinical Effectiveness at Blue Cross Blue Shield Association. "The one harm that troubles me is that the use will extend to older, frail individuals and the harms will outweigh any potential benefit."

All private insurance payors will be required to cover LDCT by January 2015 because of the grade B recommendation.

CMS will consider the topic this fall.

Regardless of what CMS decides, LDCT screening programs are moving forward.

Speaking to the panelists during the meeting, Dr. Ella Kazerooni, chair of the American College of Radiology Thoracic Imaging Panel, said the ACR approved guidelines this week for lung cancer screening activities, and also released the first edition of a lung image database and practice auditing system similar to the well-established BIRADS system used in mammography.