Lung cancer: organized screening could reduce mortality by at least 25%

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Several French pulmonologists advocate systematic screening for heavy smokers. But the High Health Authority is not of this opinion.

Chest lung cancer screening in people at risk could reduce mortality of this disease by 25% in men and 40 to 60% in women, according to a Dutch-Belgian study . These results were reported in early September at the annual conference of the International Association for the Study of Lung Cancer. Already in 2011, a US study called NLST concluded a 20% mortality decrease through screening. So many specialists, including those of the Francophone Intergroup of Thoracic Oncology or the Oncology Group of the Society of Pneumology of French Language, are they in favor of systematic screening for individuals at risk, as it is already the case in the United States.

A low proportion of false positives

In France, however, such a measure should not be forthcoming for several years. In question, a decision of the Haute Autorité de Santé (HAS) 2016, which focuses on the risk of generating false positives and the danger of irradiation. Two remarks that do not pass for the Professor Sébastien Couraud, oncologist and pulmonologist at the Civil Hospitals of Lyon, favorable to screening. This one explains indeed that the American study of 2011 had its limits: after a scanner, the test was either positive, or negative. There were 97% false positives. "Nevertheless, the goal was not to implement this technique, but to show that it was possible"says the pulmonologist.The Dutch-Belgian study is much more precise, according to him:"If the nodules are of intermediate size, we see how they evolve and we redo a scan three months later. If it has evolved suspiciously, the screening is positive."A very important nuance, since it greatly reduces the number of false positives.

As for the irradiation argument, again, many pulmonologists and oncologists are dubious. "Obviously there is some. However, the scanners of the NLST study, which lasted from 2000 to 2010, are not the same as now. At the time, a scanner was, on average, the equivalent of six months of natural irradiation. Today, this dose can be reduced by two to three times. Soon, moreover, it will be reduced and equivalent to the one we receive during a mammogram, for example", summarizes the practitioner.Remains the risk of radiation-induced cancer.If the pulmonologist recognizes that zero risk does not exist, for him, the argument is quite wobbly.In fact, such a cancer takes 10 to 30 years for to develop, and here the individuals concerned are around 60. The risk is therefore "acceptable", especially since it is greatly reduced after 50 years.

Detect cancers at an earlier stage

Today, for Pr Couraud, evidence of the effectiveness and beneficial effects of systematic screening of individuals at risk are therefore largely sufficient to begin to set up experiments, as is particularly the case in Great Britain , in Germany or Italy. Because in France, for the moment, only an operation of this kind is in progress. It is Dr. Olivier Leleu, in the Somme, who carries out a cohort study on 1,200 people. Nevertheless, after the negative opinion of HAS, the Regional Health Agency (ARS) has stopped subsidizing research. The study continues anyway, and the people involved show a real craze. The participation rate is estimated at 78% of the population at risk of the Somme. For Pr Couraud, this is proof that heavy smokers are ready to get tested.

There will, however, be no new HAS recommendations on lung cancer screening before 2020. Far too late for Pr Couraud: Early detection of lung cancer (at stage 1 or 2) leads to recovery in 90 % of cases. A widespread screening for heavy smokers and former heavy smokers, according to specialists, would save 7,500 lives each year, twice the number of people killed on the roads. "By 2020, it will therefore make 15,000 more deaths", concludes the pneumologist sadly.

"Should there be organized screening for lung cancer?" Subject posted on September 6, 2018.