PHILADELPHIA – Low-dose computed tomography (LDCT) can be extremely valuable for identifying tiny lung nodules which can indicate the earliest stages of lung cancer, according to a study of veterans at high risk of the disease.1
The study, presented this spring at the American Thoracic Society (ATS) 2013 International Conference in Philadelphia, noted that LDCT uses less than a quarter of the radiation of a conventional computed tomography (CT) scan.
“Lung cancer is the leading cause of cancer-related death and has a poor survival rate,” said Sue Yoon, FNP, nurse practitioner at VA Boston Healthcare West Roxbury Division. “Most of our veterans in these ages have a heavy smoking history, and early screening is desirable to improve outcomes. Our study was undertaken to learn how often we would discover significant abnormalities and how to adapt our existing processes and interdisciplinary approaches to accommodate additional patients.”
The National Lung Cancer Screening Trial (NLST) found that LDCT resulted in a 20% reduction of lung cancer mortality compared with chest X-ray among heavy smokers aged 55 to 74 years.
The Boston study involved 56 patients, median age 61 to 65 years, with a smoking history of more than 30 pack years or of 20 pack years and one additional cancer risk factor, such as occupational exposure to carcinogens or personal or family history of cancer or chronic obstructive pulmonary disease (COPD).
Based on the LDCT scans, of each patient, the researchers found that 31 patients had a nodule of 4 mm or larger or another abnormal opacity, of which six were deemed suspicious for malignancy. The study also found that 34 patients had more than one nodule, with four patients diagnosed with biopsy-proven lung cancer.
“Our preliminary rate of lung cancer diagnosis after the first round of screening was 7%, which was significantly higher than NLST group, which had a preliminary rate of 3.8 percent at its first round,” Yoon said. “In addition, detection of nodules larger than 4 mm was 55% in our group compared with 27% in the NLST group.”
She suggested three reasons for the difference in nodule prevalence rates between the current study and the NLST:
- The Boston VA study had much smaller numbers than the multicenter NLST;
- The scanning technology used during the current trial had advanced since the earlier NLST trial was conducted;
- The VA population was predominantly male and most patients had COPD, unlike the NLST study.
“Our previous experience with diagnosing and managing a high volume of incidentally discovered pulmonary nodules suggested that a low dose CT scan screening program, in which patients are screened annually, could be a substantial undertaking,” Yoon said. “Considerable effort goes into each step of the process: selecting patients, tracking abnormalities, further selecting patients with suspicious abnormalities for additional diagnostic and therapeutic interventions.
“Although we plan to continue and expand the LDCT screening program, this will require additional planning and, potentially, resources,” she added. “Currently we are using a gatekeeper approach, to ensure tracking of nodules and other abnormalities that are discovered during screening LDCT.”
- Yoon SH, Goldstein R, Jatil A, Arndt W, Haw SJ, et al. (2013, May). Abstract 29154: Low Dose CT Lung Cancer Screening Experience At A VA Medical Center. Presented at the ATS 2013 International Conference, Philadelphia, PA.