Screening for lung cancer with low-dose chest CT is nowhere near prime time
I feel compelled and inspired to comment on low-dose chest CT (LDCT) for lung cancer screening after reading this nice narrative review called Beyond the Guidelines in the most recent Annals and a recent virtual discussion I had with some third-year students.
Despite the USPSTF grade B rating, I believe that routine LDCT for lung cancer screening is NOWHERE near prime time.
The narrative in this week's Annals of Internal Medicine covers a lot of the issues, so I won’t recapitulate the article completely. But here are my big problems with this blanket recommendation from the USPSTF and other professional societies endorsing widespread use.
Clearly, not all patients are of equivalent risk, and not all CT results are of equivalent risk. It really needs to be easy for primary care physicians like me to access and use risk prediction models and radiographic scoring systems like the Lung-RADS model to help me understand my patient’s risk.
Screening results in many harms including radiation, cost, and probably most importantly false positives. False positives can actually cause serious harm -- INCLUDING DEATH -- to patients. Yes, in the main trial from which data are derived, LDCT saved lives, but there were people that appear to have died from their diagnostic work-up too. As Dr Schwartzstein points out in the Annals article, the absolute risk reduction (ARR) for screening LDCT is pretty minuscule:
Screening reduced the chance of lung cancer death by only 0.3% and exposed the patient to possible false-positive results with subsequent unnecessary tests and interventions and anxiety during the wait for a repeated scan.
Very few primary care physicians in this country -- including me -- are adequately informed, have adequate decision support, and have adequate time and clinical support to implement this recommendation on a wide scale. Who has time to fully counsel patients on the risks and benefits? Who is going to follow-up abnormal CT scans? How will we manage all the follow-up testing that may be needed such as results from CT-guided biopsy? At what point do competing causes of death outweigh cancer risk, and thus when will screening stop?
USPSTF grades change as more evidence emerges! The medical community once had greater enthusiasm for prostate cancer screening. Of course, in 2002, mammography in 40-49 year-old women was still considered a grade B recommendation (and is covered by the Affordable Care Act as if it were still grade B). The medical community, and primary care physicians in particular, are still struggling with how to screen for these cancers -- despite having much more data on screening trials for these two other cancers.
Does screening LDCT make sense for some people? Yes, particularly for motivated patients with a very high risk of lung cancer and limited competing health problems. In these situations, I’m confident LDCT can save lives.
But I also don’t want to take a “fools rush in” approach, and I definitely don’t want to be looking back 10 years from now saying, “It looks like LDCT was the PSA of 2015, a failed promise that created more problems than it solved.”