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MINI 36 - Imaging and Diagnostic Workup (ID 163)
- Event: WCLC 2015
- Type: Mini Oral
- Track: Screening and Early Detection
- Presentations: 1
MINI36.08 - 18F-FDG PET Imaging Utilization in the National Lung Screening Trial (ID 539)
18:30 - 20:00 | Author(s): M.K. Gould
The National Lung Screening Trial (NLST) showed that chest CT screening for patients at risk for lung cancer reduces lung cancer mortality compared to Chest X-Ray (CXR) screening, but with considerable costs due to a high rate of false positive findings. The use of FDG PET has been advocated as a diagnostic tool to aid clinicians in evaluating nodules that may or may not be cancer, but no investigations to date have ascertained current practice patterns in a large group of patients across the U.S.
Using data from the NLST, we determined the appropriateness and characteristics of diagnostic FDG PET use in patients with an abnormal finding (defined as a ≥ 4 mm nodule) during lung cancer screening via CT or CXR. Diagnostic FDG PET consisted of either a PET alone or combined PET/CT, which was done prior to a lung cancer diagnosis but after an abnormal finding. Appropriateness was defined as diagnostic FDG PET use for nodules ≥ 8 mm. We used multivariable logistic regression techniques to assess factors associated with diagnostic FDG PET use.
Of 9,964 patients with an abnormal finding during any of the three rounds of screening, 1,206 (12%) had a diagnostic FDG PET scan at 33 different medical centers across the U.S. (Table 1). Forty percent (n = 484) of these scans were recommended by a radiologist as a follow-up for an abnormal finding. Twenty-seven percent (n = 331) were performed for nodules less than 8 mm, and of these 24% (n = 81) were recommended by radiologists. There were no regional differences in PET use across U.S. areas with endemic fungal disease but patients from the Northeast and Southeast were twice as likely as the West to have a PET scan after a positive screen. Older age, nodule size ≥ 0.8 –2.0 cm, upper lobe location and a spiculated nodule border were associated with increased diagnostic FDG PET use.
This is the first study to describe differential FDG PET use across the U.S and by medical specialty. Importantly, PET imaging was used inappropriately for small nodule evaluation in one out of four cases. Future studies should characterize associated costs and whether better adherence to current national guidelines can reduce such costs. Figure 1