Prospective Multicentre Study for the Application of Telomere Measurement Technology as a Tool for Lung Cancer Diagnosis

Inclusion Criteria: Case Group: * Person aged 45 years or older at the time of signing the consent form. * Person with a current anatomopathologically confirmed diagnosis of small-cell or non-small cell lung cancer. * Not having received any oncological treatment prior to sample collection (surgery, radiotherapy, or systemic treatment with chemotherapy or immunotherapy). Control Group: Cohort A (High risk controls): * Person aged 45 years or older at the time of signing the consent form. * High risk of lung cancer, defined as having a smoking history of at least 20 pack-year and currently smoking or having quit within the past 15 years. * No diagnosis or suspicion of lung cancer. Asymptomatic individuals who have undergone a chest computed tomography (CT) scan for lung cancer screening within the 12 months prior to signing the informed consent and as part of routine clinical practice, with a LUNG-RADS score of 3 or lower, will be included. Cohort B (Low-risk controls): * Person aged 45 years or older at the time of signing the consent form. * Without high risk of lung cancer according to the criteria defined in cohort A. * No diagnosis or suspicion of lung cancer. Exclusion Criteria: * History of any malignant neoplasm, except for subjects with tumors in localized stages who have undergone radical treatment and have been disease-free for at least five years. * Patient diagnosed with lung cancer who has already started oncological treatment before sample collection. * Patient who has undergone a biopsy or any invasive procedure or minor surgery less than 48 hours ago. * Patient who has undergone major surgery less than 7 days ago. * Patient with severe chronic kidney disease, defined as a glomerular filtration rate below 15 ml/min. * Patient with severe liver disease, defined as Child-Pugh C. * Active infection, or treated less than 4 weeks ago. * Vulnerable population, for example, minors, prisoners, pregnant women, adults physically or mentally incapable of giving consent.