Lung cancer screening, which can detect tumors at an earlier stage, may be even more important for people living with HIV. HIV-positive people are more likely to smoke, and some studies show they have a higher rate of lung cancer than the general population. The U.S. Preventive Services Task Force recommends annual lung cancer screening using low-dose CT scans for people ages 50 to 80 who have at least a 20 pack-year smoking history. A small Spanish study suggests that screening HIV-positive people for lung cancer results in a high diagnosis rate with few unnecessary procedures. Among 141 people seen at a Madrid HIV clinic, 52 (37%) had evidence of lung nodules. Those with suspicious nodules underwent invasive diagnostic procedures, such as biopsies, and five were diagnosed with lung cancer. All five underwent surgery, as did an additional four people who turned out not to have cancer. The diagnosis rate was 3.6%, meaning 28 people would have to be screened to detect one case of lung cancer.