August 2019, Volume XXXIII, No 5
An underutilized, superior screening tool
Low-dose CT scans for lung cancer
Early detection of all forms of cancer leads to improved survival rates. When breast cancer is detected early and is in the localized stage, the five-year relative survival rate is 99–100%. From 1989 to 2016, as mammograms became better utilized, breast cancer mortality decreased by 40% (preventing more than 340,000 deaths). In 2015, the National Institutes of Health reported that 71.6% of women had received a mammogram. Screening for colon cancer has also showed significantly improved outcomes.
In the case of lung cancer, screening has been less successful.
Low-dose CT scans: effective, but underutilized
In addition, the National Lung Screening Trial showed that in 2011, screening people with risk factors for lung cancer with a low-dose CT scan (vs. chest x-ray) showed a 20% decrease in lung cancer deaths and a 6.7% decrease in all-cause mortality (deaths due to any factor, including lung cancer). This study showed a 1.1% lung cancer detection rate with a 24% “false-positive” rate (nodules > 4mm). Four percent of false positives were found to have cancer. Approximately 8 million people living in the United States are eligible for annual LDCT screening for lung cancer.
Lung cancer is the ... leading cause of cancer death in the United States.
Guidelines and statistics
In 2013 the U.S. Preventive Services Task Force recommended annual LDCT screening for lung cancer in adults aged 55 to 80 years who have a 30 pack-year smoking history and currently smoke or have quit within the past 15 years. Screening should be discontinued once a person has not smoked for 15 years or develops a health problem that substantially limits life expectancy or the ability or willingness to have curative lung surgery.
Statistics from the Nelson Study, presented by the American College of Radiology at the 2018 IASLC World Conference on Lung Cancer, showed that annual lung cancer screening with LDCT in high-risk patients reduced lung cancer deaths by 26 percent in men and up to 61 percent in women (up to a 44% reduction overall if male and female cohorts were evenly split). Given that the American Cancer Society predicts 142,670 lung cancer deaths in the U.S. in 2019, widespread screening could save up to 62,000 American lives each year.
The Nelson Study reinforces three important points about lung cancer screening policy:
Low levels of LDCT screening
Despite these reports and recommendations, a cross-sectional study presented before the 2018 annual meeting of the American Society of Clinical Oncology showed that less than 4% of those who are eligible for LDCT lung cancer screening have undergone the procedure. Among adults aged 55–80 years who were at risk for lung cancer due to smoking, just 5.9% had had an LDCT in the year prior to 2015.
What is the root of this disparity? Unlike breast and colon cancer screening, a patient’s primary care physician must approve the patient for a lung cancer screening exam during a shared decision-making visit. Providers may not be aware of the effectiveness of LDCT and its referral guidelines, or may be concerned about costs and false positives. Patients may be concerned about the potential for shame and blame that may be associated with their smoking, making them reluctant to be screened. Social risk factors may make it difficult for patients to seek treatment.
Regarding the cost-effectiveness of lung cancer screening, actuarial simulation models predict that over the next 15 years, 985,284 quality-adjusted life years (QALY)—a generic measure of disease burden, including both the quality and the quantity of life lived—could be saved with screening. With the addition of smoking cessation to that screening process, the cost utility ratio of quality-adjusted life years could be reduced from $28,240 to $16,198 per life year gained.
Annual lung cancer screenings in a high-risk cohort of adults aged 50–64 is highly cost-effective at $28,240 per QALY gained, compared to both the currently accepted cost-effectiveness threshold of $109,000 per QALY gained, and the more conservative threshold of $50,000 per QALY gained. This is similar to cost-effectiveness of mammographic screening for breast cancer and compares favorably to colonoscopic screening for colon cancer.
A patient’s primary care physician must approve the patient for a lung cancer screening exam.
There is no question that false positive cause stress, but compared to the alternative, patients are willing to endure a few weeks of stress. The process of lung cancer screening will continue to improve, and this will happen as more patients are screened. And it should be noted that psychological studies show that a patient’s worry about false positives is short-lived, with no lasting effects. Partly in response to this concern, most centers have instituted multidisciplinary evaluations of suspicious nodules to determine an optimal way to manage them and to better counsel patients. Certainly, there remains intensive research effort to improve LDCT screening by evaluating biomarkers to decrease the false positive and false negative results.
Non-smoking causes of lung cancer
Approximately 50% of lung cancer patients are nonsmokers at the time of diagnosis. Up to 20% of lung cancer patients never smoked. Smoking is one cause of lung cancer, but radon, asbestos, family history, unclean air, and other chemicals are also cited as causes of lung cancer. Lung cancer patients, whether they smoked or not, report unkind comments and judgment after being diagnosed. This stigma can lead to feelings of hopelessness.
Studies from the National Institute of Mental Health and other agencies have shown that lung cancer is associated with high levels of depression and anxiety. Depression, also known as major depressive disorder or clinical depression, is a serious mood disorder that affects how a person feels, thinks, and handles daily activities. Anxiety, which can show up as generalized anxiety disorder or panic disorder, is also a mood disorder that can affect daily activities. Although the projected outcome for lung cancer patients has improved as treatment evolves, lung cancer is still the leading cause of cancer deaths. This fact is a likely contributor to the increased incidence of depression and anxiety among lung cancer patients. It is estimated that one in four persons with lung cancer experiences periods of depression or other psychosocial problems during and after treatment. Other studies have shown rates of 43–47% of patients with lung cancer experiencing depression.
While smoking causes heart disease and other cancers, a diagnosis of lung cancer—more than any other smoking-related disease—generates significant, unkind stigma for some patients. While many diseases are caused by unhealthy personal choices, lung cancer patients receive the unkind comments and blame for their disease. This may further explain the high level of anxiety and depression suffered by smokers.
A disease that has claimed up to 160,000 lives annually in recent years calls for aggressive screening and drastic measures from all of us who hold some responsibility for the health of our communities and the well-being of our families. Low-dose CT screening is up and coming and the next “big” thing in medicine, one that could yield results similar to those achieved through screenings for breast and colon cancer.
The Minnesota Cancer Alliance identified the following goal in its Cancer Plan Minnesota 2025 Objective 4: “Increase low-dose CT scan screening among persons at high risk for lung cancer.”
Please join us at the 2019 Midwest Lung Cancer Summit (www.tinyurl.com/mp-torrison).
Nancy Torrison is executive director of A Breath of Hope Lung Foundation, a Minnesota 501(c)(3) nonprofit whose goal is to improve the five-year survival rate for lung cancer. Learn more at www.abreathofhope.org.
© Minnesota Physician Publishing · All Rights Reserved. 2019
ung cancer is the second most common cancer in men and women and the leading cause of cancer death in the United States. The American Cancer Society estimates there will be 228,150 new cases of lung cancer and 142,670 deaths in the United States in 2019. Nearly twice as many women die of lung cancer as breast cancer. Seventy percent of lung cancer cases are not diagnosed until stage 3 or stage 4.
Manish R. Patel, DO, is a practicing oncology physician at the Masonic Cancer Center and Professor of Medicine, Division of Hematology, Oncology, and Transplantation at the University of Minnesota.