Tuesday, November 18, 2014

Shared decision-making for lung cancer screening: will it work?

- Kenny Lin, MD, MPH

Last week, the Centers for Medicare & Medicaid Services (CMS) officially proposed coverage for annual low-dose computed tomography (LDCT) screening for lung cancer in current or former smokers age 55 to 74 years with at least a 30 pack-year history. In doing so, CMS followed the lead of the U.S. Preventive Services Task Force, which had previously given a "B" grade recommendation for screening in a similar population through age 80 years.

In the November 1st American Family Physician cover article, Dr. Thomas Gates reviewed concepts and controversies in cancer screening. Dr. Gates observed that in the 1960s and 1970s, physicians were misled by lead-time and length-time bias into believing that screening smokers for lung cancer with chest radiography saved lives, when in fact, it did not. He also noted that although LDCT screening has reduced lung cancer and all-cause mortality in a randomized controlled trial, adverse effects include a high false-positive rate, uncertain harms from radiation exposure, and overdiagnosis (leading to potentially unnecessary treatment). For these reasons, the American Academy of Family Physicians decided not to endorse the USPSTF recommendation. In an editorial published earlier this year, AFP Contributing Editor Dean Seehusen, MD, MPH elaborated on arguments against routine LDCT screening.

Notably, CMS has proposed to pay for not only the LDCT itself, but also for a "counseling and shared decision making visit" with a physician to review benefits and harms of lung cancer screening and emphasize smoking cessation (in current smokers) and continued smoking abstinence (in ex-smokers). This element is critical, as Dr. Gates observed in his article:

Perhaps the most important issue with low-dose CT screening is that it is a costly, high-tech response to what is essentially a behavioral and lifestyle problem. Smoking is responsible for 85% of lung cancers; convincing persons to quit smoking (or to not start) is far more effective in preventing lung cancer deaths than low-dose CT screening.

Shared decision-making is increasingly recommended by screening guidelines, but I worry that these difficult discussions may not actually take place, even if family physicians are paid to initiate them with patients eligible for LDCT screening. Will clinicians merely go through the motions and just order the test, as happened with prostate-specific antigen testing for prostate cancer and screening mammography for women in their 40s? What do you think?