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Genetic information influences lung cancer risk, may improve adherence
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DENVER — The lung cancer risk classification for more than one-quarter of current or former smokers changed when their clinical risk profiles accounted for genetic information, according to study results presented at the American Thoracic Society International Conference.
Individuals reclassified in the highest risk category based on this genetic information demonstrated a higher rate of adherence to follow-up screening with low-dose CT scans, results showed.
The U.S. Preventive Services Task Force recommends adults aged 55 to 80 years with a 30 pack-year smoking history who either still smoke or quit within the prior 15 years undergo annual screening with low-dose CT.
The recommendation is based in part on the results of the National Lung Screening Trial (NLST), which included 53,454 adults aged 55 to 74 years who were at high risk for lung cancer. Results showed participants who underwent annual low-dose CT demonstrated a 20% reduced risk in lung cancer mortality compared with those who received chest X-rays.
However, outside clinical trials, lung cancer screening adherence often ranges between 50% and 60%. Also, a person’s perception of risk appears to be a key factor in screening adherence, according to study background.
Robert P. Young, MD, PhD, associate professor of medicine and molecular genetics at the University of Auckland in New Zealand, and colleagues conducted the community-based REACT study to determine whether a gene-based risk test altered lung cancer risk assessment.
The researchers also attempted to determine whether personalized genetic data — which revealed the absence or presence of risk single nucleotide polymorphism (SNP) genotypes — influenced study participants’ adherence to follow-up screening after a positive CT scan.
The analysis included 157 current or former smokers, all of whom were aged older than 50 years and had at least a 20 pack-year smoking history. All participants agreed to undergo gene-based risk testing for lung cancer.
Young and colleagues used these results — along with age, personal history of chronic obstructive pulmonary disease and family history of lung cancer — to calculate a composite lung cancer risk score. They then assigned participants to one of three risk categories: moderate risk, high risk or very high risk.
Results showed SNP genotype data influenced overall lung cancer risk classification in 88% of study participants, making it a more influential factor than age (68%), family history of lung cancer (29%) and self-reported COPD (15%).
The addition of the genetic information led to 44 patients (28%) being reassigned to a different risk category.
Overall, nearly two-thirds (63%) of study participants demonstrated timely compliance with the CT screening follow-up protocol. Participants assigned to the very high risk group appeared considerably more likely to follow the screening protocol than those in the high risk and moderate risk categories (71% vs. 52%; OR = 2.3; P < .05).
“Not only does adding personalized genetic data contribute to a better assessment of lung cancer risk, it appears to improve screening adherence,” Young said in a press release. – by Mark Leiser
Reference:
Young RP, et al. Abstract 63646. Presented at: American Thoracic Society International Conference; May 15-20, 2015; Denver.
Disclosure: The researchers report no relevant financial disclosures.