New Blood Test Aids in Lung Cancer Screening

The US Preventive Screening Task Force updated its recommendations in 2021 for screening patients with  increased risk for lung cancer. Current guidelines call for providing a low radiation dose CT scan of the lungs annually for patients 50- 80 years old who have a smoking history of twenty pack years (calculated number of packages smoked per day x number of years smoking) and are still smoking or have quit within the last 15 years. These expanded criteria reduced the age to 50 from 55 and pack years from 30 to 20 years.  The recommendation is based on research showing that these criteria reduce deaths due to lung cancer by 20% as seen in the National Lung Screening Trial.

Despite this recommendation, many smokers who meet these criteria never get tested. Access to CT scans is one problem along with financial costs. For this reason, a group of researchers at MD Anderson Medical Center, led by Sam Hanash, MD, PhD, professor of clinical cancer prevention, developed a 4-panel blood test to screen for lung cancer. Their four test blood panel results were published in the Journal of Clinical Oncology on January 7, 2022.

The researchers then combined the results of the blood test with low dose CT scans of the chest and found that the accuracy of this method was far more sensitive than performing lung CT scans alone in the groups recommended for the procedure by the USPTF guidelines. Using the blood test and the low dose CT scan of the lungs, they found 9.2% more lung cancer cases for screening and reduced referrals for further evaluation by almost 14%

The blood test is still in the research phase and not available commercially for screening just yet. It will have to go through the full Food and Drug Administration (FDA) approval and evaluation process first.

The panel included tests for surfactant protein B, cancer antigen 125, CEA and cytokeratin-19 fragment. Currently the Ca125 test and CEA are available through commercial labs but there were no comments or recommendations from the authors or reviewers about whether clinicians should be using those two tests now with low dose lung CT scanning for screening.

Need To Expand the Recommendations for Screening for Lung Cancer in Former Smokers

In 1976 when I began my internship in internal medicine almost all cigarette smokers 35 years of age or older received an annual chest x ray to screen for lung cancer. In the 1990’s as managed care and insurers’ stopped paying for these screenings, we were told by the experts that the cost of saving one life by looking at every smoker was not cost effective. Insurance companies stopped paying for these films at the same time that medical advisory boards insisted on clinicians sending their chest x-rays out to be read by radiologists, adding extra costs to each film.

The practice of routine screening virtually disappeared. With it came a large increase in the number of smoking related deaths from lung cancer. It took the “experts” almost two decades to realize the errors of their decision.

In 2014 the US Preventive Services Task Force endorsed performing low dose computed tomography (CT Scans) in patients who were a high risk for lung cancer. This group was defined as individuals aged 55 to 80 years who had smoked at least 30 pack years (computed as number of packages of cigarettes smoked per day times the years the individual smoked) in individuals who continued to smoke or had quit within the last 15 years. The data to back up this recommendation came from Ping Yang, MD, PhD and colleagues at the Mayo Clinic. Their research and the new recommendations have helped reduce lung cancer deaths by 20%.

Since these recommendations were instituted, Dr. Yang and colleagues have continued to evaluate the guidelines. They found that individuals who quit smoking 15 -30 years ago are being diagnosed with lung cancer at a rate of 12-17 % of the newly diagnosed cases. They consequently are now recommending that we screen all adults 55- 80 with a 30 pack year history even if they quit more than 15 years ago.

The US Preventive Services Task Force which produces the recommendations that insurers consider has not yet endorsed this suggestion. In our practice we will be recommending low dose CT lung scanning annually on all our smokers who meet the Mayo Clinic criteria. If you, as my patient, fall into that group and have not been getting annual low dose CT Scanning of the lung for lung cancer detection please let us know so that we may set up a surveillance program. We understand the increased cost and ionizing radiation exposure that CT Scans involve but Dr Wang’s research suggests that the benefits outweigh the costs and risks.

Smoking Increases the Risk of Breast Cancer, Lung Cancer and Colon Cancer in Women

The Surgeon General of the United States issued another report on the dangers of smoking and its addictive potential last year.  At the time of release I was quite skeptical about the cost of the report and the need to remind Americans again that smoking is dangerous for you.  Then along comes a detailed review of the National Surgical Adjuvant Breast and Bowel Project. According to Stephanie Land, PhD, of the University of Pittsburgh, long-time smokers had a 59% increase in the risk of invasive breast cancer compared with nonsmokers.  The study looked at the links between four types of malignancy: breast, lung, colon, and endometrial cancer with smoking, alcohol use and leisure time activity.  The findings suggested that:

1.       Women who had smoked between 15 and 35 years had a 35% increase in the risk of breast cancer compared to non smokers. In that same group, if a woman smoked more than a pack a day she had a five – fold higher risk than non smokers.

2.       Women who had smoked 35 years or more had a 59% increase in the risk of breast cancer. These long-term smokers had a 30 times higher risk of lung cancer than non smokers.

3.       The risk of colon cancer among long–term smokers was five times higher than among non smokers.  A drink of alcohol a day reduced the risk of colon cancer by 65% compared to non drinkers.

4.       Inactive women had a 72% increased risk of uterine endometrial cancer compared to active participants in the study.

The study of almost 14,000 women highlighted the benefits of improving life style choices.  While researchers search for drugs and medication to prevent these life threatening illnesses, the study pointed out the benefits of altering the life style choices of women to prevent the development of cancer.

It is clear that smoking prevention and smoking cessation programs can do far more to prevent these cancers than pharmaceuticals. With cutbacks on funding for public health and the elimination of most health and hygiene classes in middle schools and high schools due to financial constraints, I wonder if we are being penny wise and pound foolish.