Lung cancer is the most common cause of cancer-related death in the world: 1.37 million deaths per year. In Spain, 30,000 cases are detected annually and 23,000 people die from this cause, according to the Spanish Society of Pulmonology and Thoracic Surgery (Separ). Survival is less than 15% five years after diagnosis. This high mortality rate is because, at the time of diagnosis, the disease is in an advanced stage in 70% of cases. Symptoms often appear late, and surgery, the treatment that provides the highest cure rates, is only indicated in the early stages of the disease.
Early diagnosis is key to increasing survival in lung cancer. It is achieved through low-dose computed tomography (CTBD), a test that allows the tumor to be identified at an early stage, when it forms small nodules in the lung before spreading to other areas of the body. In this sense, at the end of 2022 the European Commission updated the recommendation for cancer screening. Lung, prostate and gastric cancer screening was added to the early detection of breast, colorectal and cervical cancer. The EC urges states to incorporate advanced detection in a staggered manner from 2025.
Scientific societies, patient associations and foundations consider that screening by low-dose CT scans only in risk groups would constitute a paradigm shift in the lung cancer situation. In general, smokers or ex-smokers – who have given up smoking less than 15 years ago – aged between 55 and 74 are considered to be at risk. However, a report commissioned by the Ministry of Health to the Canary Health Service and the Galician Agency for Health Knowledge Management has cooled expectations, alluding to the high cost of screening in relation to possible benefits, to the difficulty in identifying the target population or to the risk of false positives or overdiagnosis. “The balance between the benefits and risks of lung cancer screening with TCBD is complex due, in part, to the great heterogeneity and lack of consensus on essential aspects of the process,” the paper states.
Juan Carlos Trujillo, clinical head of Thoracic Surgery at the hospital of Sant Pau, puts into perspective the economic arguments of the report – every TAC, which in a generic way every person should be done annually and during the 15 years following the abstinence, costs between 60 and 80 euros – and disagrees on the alleged difficulty in identifying the target population: “There is a risk factor that marks a much higher probability of cancer, which is tobacco. We have a population that needs to be attacked. Also, the older, the more likely. We already have two characteristics that allow us to delimit the population. Although age and smoking are not perfect variables, they do allow us to make a first selection, a risk model to achieve a more precise screening. Breast cancer detection isn’t perfect either: it only discriminates against age and sex, you’re also leaving other people out.”
Two large studies support the benefits of screening. In the United States, the NLST showed that screening by imaging reduced lung cancer mortality in people with a history of smoking by 20%, and the European Nelson study put the reduction at 26%.
But approximately 50% of individuals who develop lung cancer do not meet the criteria currently used to enter a screening program. About 15% of those affected have never smoked and there is a significant percentage of patients under the age of 20, for example.
Luis Seijo, pulmonologist at the University of Navarra clinic and coordinator of the Thoracic Oncology area of ??the Separ, is the only Spanish participant in the Solace project, a consortium made up of 33 European institutions dedicated to the implementation of screening in Europe and to the cost-benefit feasibility study. “No one hesitates to spend money on an immunotherapy treatment that costs up to 400,000 euros. Are we willing to spend on treatments and not on prevention? Where do we set the limits, who sets them?”, he questions regarding the report commissioned by the Ministry of Health.
According to Seijo, the evidence for the benefit of screening, as well as the consensus of the scientific community, is unquestionable. But it is necessary to continue to tighten the siege of the candidates. The more tests, the more economic cost, the lower the detection rate and probably the more false positives. “We must continue to investigate, to know why a person who has smoked a lot has not developed lung cancer and another who has never smoked does. If we manage to find any marker in the blood about the risk of developing the disease, it should enter the detection program, even if it does not correspond to the criteria of age and smoking”.
Seijo has no doubt that, sooner or later, screening will be incorporated into the Social Security service portfolio (and will not, in his experience, cause smokers to continue smoking so that they can be sure that the tumor will be detected in time). “The United States is doing it – he says -. Europe proposes it, our neighboring countries are making ambitious experiences. I don’t know when it will be, but I want it to be as soon as possible because it’s something I’ve been doing for twenty years and I’ve seen the benefit it brings and the little harm it causes to individuals who have some finding that is not important.” Trujillo and Seijo co-lead the Cassandra lung cancer screening project that will soon be launched in 20 hospitals in 14 autonomous regions.
