(RxWiki News) Findings of the National Lung Screening Trial (NLST) showed that screening long-term smokers of certain ages could reduce lung cancer deaths by 20 percent. Recommendations have been developed based on the results of this trial.
Researchers revisited the NLST findings and developed a refined model for determining who would benefit from lung cancer screening.
Lung cancer screening using low-dose CT scans is now recommended for people between the ages of 55 and 74 who have smoked a pack a day for 30 years or have been smoke-free for less than 15 years.
"Get screened for lung cancer if you've smoked for many years."
Martin C. Tammemägi, PhD, from the Department of Community Health Sciences at Brock University in Ontario, Canada, led the study.
Dr. Tammemägi's team had previously developed a lung cancer risk prediction model involving former and current smokers who participated in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial.
The two studies involved nearly 125,000 smokers and former smokers - 80,375 individuals in the PLCO and 53,202 in the NLST study.
The goal of the current study was “to modify and update our lung cancer model for current and former smokers to make it directly applicable to NLST data,” the authors wrote.
The modified model, which researchers have named In PLCOm2012, showed that a number of factors increased lung cancer risks, including: advancing age, being African American, having lower levels of education, lower BMI (body mass index), history of COPD, personal history of cancer, family history of lung cancer, currently smoking, longer history of smoking more cigarettes and a shorter period of time since quitting.
Fred Hirsch, MD, PhD, professor of medicine and pathology at the University of Colorado Cancer Center, told dailyRx News, “The new model, derived from PLCO and modified, predicted a six-year risk of developing lung cancer with high accuracy and was more efficient than NLST criteria at identifying individuals for lung cancer screening. The mortality reduction from CT screening effectiveness did not vary according to lung cancer risk,” Dr. Hirsch explained.
The authors concluded that this model may be effective in selecting candidates for lung cancer screening.
Dr. Hirsch pointed out that the studies left important questions unanswered. “What about screening of high-risk individuals beyond 55 to 74 years (the NLST criteria)? More and more patients younger than 55 get lung cancer these days. The socioeconomic statuses in the PLCO study were higher than the general population. What about high risk individuals from lower social groups? What about never smokers? More and more lung cancers are seen among never smokers, a group not included in either NLST or PLCO study.”
Dr. Hirsch continued, “Hopefully, ongoing and future studies will lead to identifying biomarkers, which can be used as adjunct to these risk models or alone, and which can identify the most optimal group of individuals suitable for lung cancer screening.
“Also, technological developments occur related to spiral CT (including volumetric assessment), which in the future eventually can improve the screening results.
“In the meantime, the results from the lung cancer screening studies of high-risk individuals are the most significant and encouraging improvement we have seen for lung cancer patients for decades, and many questions related to implementation of this will be resolved through several ongoing prospective studies.
“It is important that high-risk individuals are discussing these matters with their physicians,” Dr. Hirsch said.
An article describing the findings - "Selection Criteria for Lung-Cancer Screening" - appeared in the February 21 issue the New England Journal of Medicine. No conflicts of interest were disclosed.