“A new statistical analysis of results from the National Lung Screening Trial (NLST) concludes that performing low-dose computerized tomography screening can be cost-effective compared to doing no screening for lung cancer in aging smokers.
” ‘This provides evidence, given the assumptions we used, that it is cost-effective,’ said Ilana Gareen, assistant professor (research) of epidemiology in Brown University’s School of Public Health and second author on the new study in the New England Journal of Medicine.
“Four years ago, the vast NLST showed that low-dose helical CT scanning reduced mortality from lung cancer by 20 percent compared to chest X-rays. The study involved more than 53,000 smokers aged 55-74. Chest X-rays, meanwhile, have been shown to be no better than doing nothing to screen for the cancer.
“With the NLST’s trove of medical and cost data to work from, a research team including Gareen, senior author Constantine Gatsonis, professor of biostatistics, and lead author Dr. William Black at Dartmouth College’s Geisel School of Medicine, set out to determine the financial implications of conducting CT screening compared to not screening. The standard for this is to calculate a ratio of the costs of CT screening per person—including the test, any follow-up testing and treatment, and indirect costs—and the number of ‘quality-adjusted life-years added’ per person across the population. The quality adjustment distinguishes between living in good health and surviving but with major health problems.”
“Smokers who received abnormal or suspicious lung cancer screening results were less likely to still smoke at the time of the next year’s screen, according to study results.
“Martin C. Tammemägi, PhD, of the department of health sciences at Brock University in Ontario, Canada, and colleagues reviewed National Lung Screening Trial (NLST) data on 14,692 adults who were current smokers at baseline and did not develop lung cancer during follow-up. The median age of patients was 60.6 years; a majority were men (58.7%) and non-Hispanic white (89.5%).”
“Recent results indicate that low-dose computed tomography (LD-CT) screening reduces lung cancer mortality in high risk subjects. However, high false positive rates, costs and potential harm highlight the need for complementary biomarkers. Led by Dr Ugo Pastorino, a group of researchers from Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy, retrospectively evaluated a non-invasive plasma miRNA signature classifier in prospectively collected samples from smokers within the randomised Multicentre Italian Lung Detection (MILD) trial. Their findings indicate that microRNA signature classifier has predictive, diagnostic and prognostic value and its combined use with LD-CT may improve screening performance. The results were presented in a proffered papers session at the 4th European Lung Cancer Conference (26-29 March 2014, Geneva, Switzerland).”
Editor’s note: LD-CT is a lung cancer detection method that has been shown to reduce risk of death from lung cancer for high-risk patients. However, it sometimes leads to “false-positives,” in which suspected cancer later turns out not to be cancer. A new, non-invasive blood test to look for specific kinds of miRNA molecules was shown to be promising as a potential companion test to complement LD-CT screening.
“People who have an inherited mutation of a certain gene have a high chance of getting lung cancer—higher, even, than heavy smokers with or without the inherited mutation, according to new findings by cancer researchers at UT Southwestern Medical Center. Although both genders have an equal risk of inheriting the mutation, those who develop lung cancer are mostly women and have never smoked, the researchers found.
“People with the rare inherited T790M mutation of the epidermal growth factor receptor (EGFR) gene who have never smoked have a one-in-three chance of developing lung cancer, researchers found. This risk is considerably greater than that of the average heavy smoker, who has about a one-in-eight chance of developing lung cancer – about 40- fold greater than people who have never smoked and do not have the mutation.”
Antioxidants are chemicals that neutralize particles called free radicals that can damage DNA. Preventing such damage may help lower cancer risk for some people. However, tumors themselves can contain high levels of free radicals; by eliminating these free radicals, antioxidants may help cancer cells grow. In a laboratory, lung cancer cells treated with the antioxidants vitamin E and acetylcysteine (ACC) multiplied faster than untreated cells. Vitamin E and ACC also increased tumor growth and decreased survival time in mice with lung cancer. The so-called ‘tumor suppressor’ protein p53 can sense certain free radicals to detect cells with DNA damage and stop their growth. Antioxidants may interfere with this cancer-suppressing mechanism by reducing free radical levels. Taking antioxidants may therefore not be recommended for lung cancer patients and smokers.
Low-dose computed tomography (CT) scans are the currently recommended screening method for lung cancer in heavy smokers. However, these scans produce many false positives (identifying suspicious lung nodules when no cancer is actually present), needlessly exposing numerous people to the costs and risks of invasive follow-up procedures. Now, a large study has shown that a simple blood test may complement CT scans to reduce the false positive rate in lung cancer screening. The microRNA signature classifier (MSC) Lung Cancer assay measures the expression levels of several molecules called microRNAs to classify patients as low, intermediate, and high risk. In a trial of over 4,000 current or former smokers, the MSC Lung Cancer assay detected the vast majority of all lung cancers accurately, but produced a low rate of false positives. Moreover, the test detected some cancers up to 2 years before the CT scans.
E-cigarettes (electronic cigarettes that use a battery-powered system to deliver nicotine without producing smoke) are advertised as a safer alternative to tobacco cigarettes. However, very few studies have investigated how e-cigarettes affect lung function and lung cancer risk. Researchers examined human airway cells with mutations in the TP53 and KRAS genes, which are often mutated in the airways of current or former smokers at high risk of lung cancer. When the cells were exposed to e-cigarette vapor, they developed cancer-cell-like behaviors and gene expression changes very similar to what was seen when these cells were exposed to tobacco smoke. E-cigarettes may increase the risk of developing lung cancer in high-risk people, including current and former tobacco smokers.
The U.S. Preventive Services Task Force has published its final recommendations on lung cancer screening. The panel advises annual computed tomography (CT) scans for high-risk individuals (heavy smokers or former heavy smokers who have quit within the past 15 years) between 55 and 80 years of age. The recommendation is based on the results of a comprehensive review of the existing evidence and on modeling studies predicting the benefits and harms of different screening programs. Some experts have criticized the use of modeling data in developing the guidelines. Others consider practical concerns in implementing the recommendation, such as how to actually select those patients eligible and refer them to screening.
Increased inflammation may be a warning of elevated lung cancer risk. A recent study analyzed blood samples taken from over 1,000 patients getting screened for lung cancer. Half of the patients went on to develop lung cancer in the following years. Eleven chemical markers of inflammation in the patients’ blood were associated with an increased risk of developing lung cancer. The researchers developed an inflammation score based on the levels of four of these inflammation markers. Patients with the highest inflammation score were 2.8 times more likely to develop lung cancer than those with the lowest score (3.4 times more likely if the patients were current smokers). This inflammation score may therefore serve to identify high-risk patients in the future.