Lung Cancer Screening: Use of Low-Dose Computed Tomography

The prognosis of lung cancer (LC) correlates directly with the stage of the disease at the time of diagnosis.

We performed low-dose CT (LDCT) in asymptomatic individuals ≥50years old, smokers or former smokers of ≥10 pack-years, with no history of cancer. We followed an evaluation algorithm, according to the size and morphology of the nodules. The appropriate treatment for the LC diagnosis was given and patients were followed up for 5years.

We studied 4,951 individuals (65.4% males) with an average age of 56.89±5.26years; 550 presented nodules. Of the 3,891 nodules detected, 692 (19.57%) were considered positive, and 38 tumors (36LC) were identified. In the annual follow-up, nodules were found in 224 subjects, 288 (7.91%) of which were positive (13LC). In 80%, the study was performed with LDCT, and biopsy was indicated in 5.8% (baseline) and in 7.6% (annual) of the positive nodules. Prevalence was 0.89 and incidence was 0.1%. The sensitivity, specificity, PPV and NPV in the baseline study were 92.31, 89.54, 6.55 and 99.93%, respectively, and in the annual study, they were 76.92, 95.7, 4.52 and 99.94%, respectively. A total of 52 tumors were detected (49LC), 25 (52.08%) in stageI. The 5-year overall survival rate for LC was 58.5% and cancer-specific survival was 67.1% (75.8% in surgical patients).

LDCT integrated into an elaborate nodule detection and evaluation program is a useful tool for diagnosing early-stage LC.