The main risk factor for developing lung cancer is smoking, which is responsible for 90% of cases. The remaining 10% are due to other important factors such as “passive” smoking, residential radon exposure, asbestos, environmental contamination or other carcinogens, and family history. In other words, without tobacco, lung cancer would be a minority disease.
Not all smokers develop cancer, but today we do not have any technique that allows us to discriminate which person will develop this disease. The risk is proportional to the number of cigarettes smoked daily and the years smoked.
When you stop smoking, the risk of developing lung cancer decreases progressively, but it does not match the risk of non-smokers until approximately 20 years. It is rare to develop lung cancer before the age of 50. For this reason, not smoking and quitting continue to be the best prevention weapons against lung cancer.
Early diagnosis, the best chance of cure
Unlike other types of cancer, early detection of lung cancer is more difficult because the patient begins to experience symptoms when the tumor is already in an advanced stage.
The first studies of early detection of lung cancer date back to the 1970s and 1980s using chest X-rays and sputum cytology as tools. These studies found an individual benefit for people diagnosed with lung cancer but did not demonstrate a decrease in overall mortality.
However, at the end of the 20th century, researchers at Cornell University in New York discovered that performing a low-dose radiation CT scan (TCBD) of the chest in high-risk people (smokers or ex-smokers, ages 55 to 74 years of age, with an accumulated smoking habit of at least 30 cigarettes a day) without symptoms of any kind, small and non-extended malignant tumors can be detected that are susceptible to being definitively removed by surgery.
If this technique did not detect them, they would have gone unnoticed until they spread and produced symptoms, in which case the prognosis and chances of cure are significantly worse.
To date, experience with TCBD is extensive, and its success has generated great interest in the early detection of lung cancer. It has led to the creation of an international group of several hospitals, NLST (National Lung Screening Trial). The study of this group concluded that early diagnosis with TCBD significantly reduces mortality from lung cancer between 20% and 60%. It also meant a reduction in overall mortality of 6.7%.
The data from this study are of great importance. The generalization of this test and the implementation of official programs for the early detection of lung cancer, as they exist for breast, prostate and colon cancers, could save many lives.
However, in Spain, the National Health System does not finance this procedure. Once its effectiveness has been demonstrated, the biggest challenge we have for its implementation in Spain is to correctly identify the population at risk to which it is directed, that is, the identification of active smokers or people who have stopped smoking in the last 15 years a number smoking (one pack/day for 20 years) and who are in the 55 to 75 age range. It is essential to launch pilot projects in different Autonomous Communities that allow us to explore the best way to carry it out at a national level.