Balancing the risks and benefits of disease screening can be a tricky business. For lung cancer, screening is recommended for a specific group: people age 55 to 80, who have smoked a pack of cigarettes per day for 30 years or more, and who currently smoke or quit in the last 15 years or so. That group, according to the US Preventive Services Task Force (USPSTF), should get screened with a low-dose CT scan. And research does suggest that scans in that population could save lives — an estimated 12,000 of them per year if applied broadly.
However, recent research published in The Lancet Oncology, suggests screening could benefit even more high-risk people.
“A few recent studies, including our own, have shown that only a third of patients with lung cancer would meet the USPSTF screening criteria,” says Mayo Clinic epidemiologist Ping Yang, M.D., Ph.D., and senior author of the new Mayo Clinic-led study. “We aimed to assess survival outcomes in the two largest excluded subgroups: people who quit more than 15 years ago, called long-term quitters, and people age 50 to 54 who otherwise meet the current USPSTF smoking history and age criteria.”
Dr. Yang explains that the study focused on newly diagnosed lung cancer patients to find out what proportion would have been identified by screening under current criteria. The study used two independent patient cohorts, one from Olmsted County, Minn., and the other from referral patients, both followed for 20 years, to look into the same question.
“The common sense is that the two subgroups would have better overall survival than those meeting the criteria,” says Dr. Yang.
But they didn’t.
“We found that the people who quit more than 15 years prior to diagnosis and the younger age group have a similar risk of death to those individuals who meet all USPSTF criteria,” she says.
In this prospective, observational study, the researchers combined information from the Rochester Epidemiology Project*, Olmsted County, and patients from Mayo Clinic diagnosed between 1997 and 2015. The population included 140,000 people, 83 percent of whom were non-Hispanic white. Median follow up of patients was 6.5 years and median overall survival was almost 17 months.
Dr. Yang says that in both cohorts – community and hospital – patients’ survival (measured as risk of death) did not differ between the patients eligible for screening by USPSTF criteria and those in the two excluded subgroups.
“Our findings highlight the need to update the USPSTF screening criteria and the conventional risk assessment model based on age and smoking history,” says Dr. Yang. “Careful consideration of the optimal screening criteria is needed to guide the decision to screen individuals at high risk of developing lung cancer.”
Next, the research team plans to investigate biological markers to pin-point individuals who would benefit most from screening, as well as to identify measurable personal risk factors leading to lung cancer in never smokers, particularly in women.
Mayo Clinic authors on the paper are Yung-Hung Luo, Jason Wampfler, Dan Liu, Alex Adjei, M.D., Ph.D.; and David Midthun, M.D. Other authors include: Lei Luo, Guizhou Province People’s Hospital; Yi Wang, Wenzhou Medical University; Yuh-Min Chen, Taipei Medical University.
Funding for this work was provided by the National Institutes of Health, National Cancer Institute, and the Mayo Clinic Foundation. The authors declare no competing interests.
*About the Rochester Epidemiology Project:The Rochester Epidemiology Project (REP) is a collaboration of clinics, hospitals, and other medical facilities in Minnesota and Wisconsin and involves community members who have agreed to share their medical records for research. Using medical record information, medical scientists can discover what causes the diseases, how patients respond to medical and surgical therapies, and what will happen to patients in the future. The REP receives administrative support from the Mayo Clinic Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery.