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CT scan screening reduces lung cancer mortality

January 30, 2020

Fewer current smokers and former smokers die of lung cancer if they are screened for this disease. Men at risk of lung cancer who undergo screening reduce their risk of dying from lung cancer by 24 percent. For women, this effect may even be twice as high.

Researchers from Erasmus MC in collaboration with other centers publish these results today in the renowned medical scientific journal The New England Journal of Medicine. These findings are based on the Dutch-Belgian Lung Cancer Screening Trial (Dutch acronym: NELSON study).

Every year, around 10,000 lung cancer deaths occur in the Netherlands, 6,000 of which are men and 4,000 women. Almost a fifth of all cancer deaths are from lung cancer. Less than 20 percent of the people diagnosed with lung cancer survive their disease beyond five years. However, if lung cancer is detected at an early stage treatment is more likely to be successful.

Prof. Harry de Koning, principal researcher and Professor of Public Health, says: “Our study has shown that CT scan screening, followed by early treatment, reduces the risk of dying from lung cancer in men by almost a quarter. An important factor in achieving this was the fact that radiologists were able to detect the disease at an early stage in 60 percent of the participants through screening. Most of the lung cancers detected in the group that was not screened in our trial, were diagnosed at an advanced stage, when it is very difficult or impossible to treat. This is because symptoms of lung cancer often develop relatively late or are difficult to identify.”

The effect of screening appears to be greater for women than for men. De Koning says: “The risk of dying from lung cancer decreases by 35-55 percent in women. The number of women participating in our study is relatively small compared to the number of men, because at the start of the trial the number of women at risk in the Netherlands was low. Other studies have now also confirmed our findings.”

Prof. Matthijs Oudkerk, Emeritus Professor of Radiology and responsible for the CT scans, says: “By measuring the volume and growth rate of the abnormalities on the CT scan, the researchers were able to tell with quite some certainty whether it was lung cancer that was detected. In this way, the number of referrals to pulmonologists could be kept low: for every two people that were referred for additional examinations, one person had lung cancer.”

After ten years, data from the Dutch and Belgian Cancer registries showed that lung cancer had been detected in 341 male participants of the screening group. Data from the death registry showed that 156 of these participants with lung cancer had died from lung cancer. A total of 304 men in the control group were diagnosed with lung cancer, 206 of whom died of lung cancer.

Dr. Carlijn van der Aalst, one of the researchers: “Let it be clear that the best way of preventing lung cancer is to never start smoking. But many people were exposed to smoking in the past. Even people who have quit smoking, are still, up to ten years after they quit smoking, at high risk of developing the disease and dying from it. This study shows that we can significantly reduce the risk of dying from lung cancer.”

The NELSON study, which ran for 20 years, included almost 16,000 smokers and former smokers, of whom 13,195 were men. They were aged between 50 and 74. Half of the participants were screened and then received additional CT scans at 1, 2, and 2.5 year intervals. The other half of the participants were not screened. These groups have now been compared. The study was conducted by a large consortium and the scans and assessments were performed in Spaarne Gasthuis in Haarlem, University Medical Center Utrecht, University Hospital Leuven (Belgium), and the University Medical Center Groningen, which had the overall responsibility for all the scans.

The link to the article can be found on the website of the scientific journal The New England Journal of Medicine (NEJM).