A couple of weeks ago, a study published in Health Affairs reinvigorated the conversation about the usefulness of screenings for lung cancer. We have been among the voices questioning the widespread use of certain screenings because, in many cases, they are inappropriate, unnecessarily expensive and possibly harmful.

Now, another voice of reasoned consideration and moderation has reinforced the growing belief that for too long many diagnostic tests have been conducted not because they signify the best in medical care, but almost by habit bolstered by studies that seem significant but, on closer inspection, don't measure up.

Writing on HealthNewsReview.org, Harold DeMonaco, director of the Innovation Support Center at the Massachusetts General Hospital, said that the study authors provided some interesting numbers to back up their conclusion that insurers should screen high-risk individuals (long-term smokers who are at least 50) with low-dose spiral CT scans. That technology creates multiple images of the entire chest via X-rays, whereas a standard chest X-ray is a single snapshot of the entire chest.

“Of the 18 million or so smokers who fall into their eligibility criteria,” DeMonaco wrote, “they showed a potential for … 130,000 additional survivors of lung cancer due to early detection. It’s hard to argue that saving this many lives is not important. But the study does not look into the negative aspects of the double-edged sword that is lung cancer screening. While we are constantly berated for being anti-screening, it is important for people to understand what the risks and benefits are for any medical procedure including screenings.”

He referred to a large study funded by the National Cancer Institute (NCI) to determine whether screening with low-dose CT, as compared with chest radiography, would reduce mortality from lung cancer among high-risk smokers. We reported on that as well.

The NCI study, DeMonaco said, was sufficiently similar to the one reported by Health Affairs for its data to be relevant now. About 1 in 4 people who got spiral CT scans tested positive. If extrapolated per the current study, the numbers add up to 4.32 million positive findings. But more than 9 in 10 of those proved to be false positives. (See our post about the perils of false positives and false diagnoses.)

In revisiting this unwelcome scenario in this application, DeMonaco explained “that 4,086,720 people screened would have a false positive result. All would likely suffer from some degree of angst. Of those with false positive findings, 0.06 percent had a major complication possibly related to subsequent invasive procedures in the NCI sponsored study.”

So 108,000 people would experience a serious adverse event resulting from a procedure they had because the original scan showed falsely positive. Said DeMonaco: “Those events need to be considered when thinking about the 130,000 potential lives saved through screening. Few medical procedures are without risk and each should be viewed as a double-edged sword. Benefits as well as risks need to be considered. Reporting on just the benefits provides readers with only half the story.”

If your doctor prescribes a screening test, ask:

If you’re not satisfied with the answers, or if you don’t believe your concerns are be given fair consideration, seek a second opinion.