On December 30th
, via a publication in the Annals of Internal Medicine found here
, the United States Preventive Services Task Force (USPSTF
) announced they recommend annual screening for lung cancer with low-dose computed tomography (LDCT) in adults aged 55-80 years who have a 30 pack-year smoking history (the number of years smoking x number of packs per day, for example 2 pack/day smoking habit for 15 years equals 30 pack-years, or 1 pack/day smoking habit for 30 years also equals 30 pack-years) and currently smoke or have quit within the past 15 years. The USPSTF also recommended that screening should discontinue once a person has stopped smoking for 15 or more years, or has developed a medical condition that would preclude curative surgery if a lung cancer was to be found.
These ground breaking recommendations are a follow-up to the USPSTF recommendations released July 29th
, 2013. Since their July 29th
announcement, the USPSTF reviewed multiple data including US and European randomized clinical trials, and employed population modeling studies commissioned from the Cancer Intervention and Surveillance Modeling Network (CISNET
). The USPSTF’s support of lung cancer screening by LDCT is a departure from their last report in 2004, where they found no evidence in support of lung cancer screening by LDCT or chest x-ray or sputum analysis.So what is the USPSTF?
The USPSTF is an “independent panel of experts in primary care and prevention that systematically reviews the evidence of effectiveness and develops recommendations for clinical preventive services.” (http://www.ahrq.gov/clinic/uspstfix.htm
Agency for Healthcare Research Quality). The USPSTF offers graded recommendations from A (high certainty that the net benefit [of an intervention] is beneficial) to D (recommendation against [the intervention]). There is an alternative grade called “I” or insufficient evidence. The USPSTF provides a grade “B” recommendation for lung cancer screening with LDCT; randomized clinical trials looking at LDCT for lung cancer screening provides “moderate certainty” of the benefit to a high-risk population.So why are the USPSTF recommendations on lung cancer screening important?
Currently very few insurance plans, including Medicare or Medicaid, cover the costs of lung cancer screening. Most asymptomatic patients who fit the high risk group defined above must pay out of pocket expenses if they want a LDCT specifically for the purposes of lung cancer screening. Lesser et al demonstrated (Lesser et al, Ann Fam Med. 2011
) that from 2007 to 2009 the USPSTF recommended 15 preventative interventions for adults aged 65 years and older. Medicare partially covered 93% of the recommended services. In the same time frame, USPSTF recommended against 16 preventive services, and Medicare partially covered only 44% of those services. So although the USPSTF recommendations, per their own disclaimer, “are independent of the US Government”, the Centers for Medicare and Medicaid Services (CMS) take their recommendations seriously when determining clinical services coverage.What information is the USPSTF using for their recommendations?
Although the USPSTF reviewed multiple studies and randomized clinical trials, the largest study they looked at is the National Lung Screening Trial (NLST
). The NLST was a US, academic, multi-hospital randomized clinical trial comparing chest X-ray to LDCT for screening in patients considered high risk (aged 55-74, 30 pack-year smoking history, current smoker or quit within 15 years at point of eligibility). Patients underwent three annual screening exams. The results demonstrated that LDCT reduced death from lung cancer by 20% compared to chest X-ray, and overall death from all causes by 6.7% compared to chest X-ray. 70% of the lungs cancers found by LDCT were stage I or II, or the earliest most curable stage.Why is lung cancer screening important?
Currently 75% of patients who are diagnosed with lung cancer are diagnosed at stage III or IV, or locally advanced or metastatic stages. Although there have been improvements in targeted molecular therapy as illustrated here
, long term survival for patients with advanced stage lung cancer is difficult. As mentioned above, 70% of the lung cancers found by screening LDCT were early stage tumors, where 5 year survival is 75-80%. This is an incredible “stage-shift” which will have marked benefits on society.