Making Sense of the USPSTF Recommendations on Lung Cancer Screening

On December 30^th , 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 29^th, 2013. Since their July 29^th 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.

What else did the USPSTF say? The USPSTF highly recommended that smoking cessation be incorporated into any screening program. This brings up the important point; any lung cancer screening program should be a comprehensive screening program. What does that mean? It means that a patient should enter the appointment with a referral from a primary-care provider. This allows for communication of results, and continuity of care. All active smokers should undergo smoking cessation counseling. Patients with abnormal lung findings should have the opportunity to receive counseling and guidance form a lung cancer screening program clinician. In addition the screening program should be multidisciplinary, and have frequent continuous quality improvement meetings to oversee the efficacy and results of the program. The UC Davis Comprehensive Lung Cancer Screening Program fits theses criteria, and is comprehensive in its design and implementation.

Is there any controversy to the USPSTF recommendations? Not controversy, but the USPSTF recommendations focus on a group that is defined as high risk (aged 55-80, 30 pack-year smoking history, current smoker or quit within 15 years), but what about patients that do not fit the smoking criteria but are also at risk for lung cancer? Those patients include, but not limited to those individuals who have been exposed to asbestos, have COPD, high levels of radon exposure, history of interstitial lung disease and a family history of lung cancer. The National Comprehensive Cancer Network recommends LDCT screening in patients who are aged 50-74, 20 pack-year smoking history and have one additional risk factor. Risk factors include the following: personal lung cancer history (>5 years), family history of lung cancer (first degree relative), chronic lung disease, and carcinogen exposure (excluding second hand smoke exposure). We have also incorporated the NCCN guidelines into the UC Davis Comprehensive Lung Cancer Screening Program.

How can I learn more about lung cancer screening LDCT? There are a number of patient-centered resources. The National Cancer Institute has a NLST Patient and Physician Guide. The American Lung Association offers an online patient-centered tool found here, that helps patients determine if they are candidates for LDCT lung cancer screening. A great social media community is #LCSM, which regularly has Twitter chats that discuss lung cancer issues, and has an associated blog. Finally the representatives from the UC Davis Comprehensive Lung Cancer Screening Program are available to answer questions at 916-734-0655.