Table 3 lists the κ results for the strength of agreement between pulmonologist and radiologist. Agreement for primary lung cancer was very good: 0.94 (95% confidence interval [CI], 0.89-0.99). With respect to group 1, agreement was perfect: 1.0 (95% CI, 1.000-1.000). Benign neoplasm had the weakest agreement. There was no statistical difference between pulmonologist and radiologist determinations across size-based groups.Agreement between pulmonologist and FD was almost perfect. The major discrepancy between the sets of reviewers remained benign neoplasm and infectious/inflammatory etiology.
Of the 111 study patients, 68 (61%) and 72 (65%) were suspected of having primary lung cancer by pulmonologist and radiologist, respectively. However, only 60 (54%) actually had primary lung cancer; the differences were not statistically significant (P = .27 and .1, respectively). No cases were reclassified as primary lung cancer on final pathology.
Infectious/inflammatory etiologies did not always have positive cultures. Those with positive cultures included Streptococcus (S) viridans, Rhodococcus equi, Blastomyces dermatitidis, S constellatus, S anginosus, S intermedius, and Histoplasma capsulatum. Benign neoplasms included radiation injuries, benign fibrous tumor of the pleura, and hamartoma.
Pulmonologists and radiologists had identical high sensitivities for primary lung cancer: 1.0 (95% CI, 0.94-1.00). Specificities were 0.84 (95% CI, 0.77-0.84) for pulmonologists and 0.77(95% CI, 0.69-0.77) for radiologists, and the difference was not statistically significant (P = .28) (Table 4).
Discussion
Computed tomography scans are performed to evaluate a variety of diseases. An estimated 7 million CT scans are performed in the U.S. annually.6,12 As the National Lung Screening Trial recommendations are followed more routinely, almost 9 million peoplecould become candidates, adding to the already large number of CTscans to be evaluated.13
Radiologists would understandably read most of these patients’ scans. However, patients referred to tertiary-care centers usually bring CT images with them; even scans performed at UAMS and CAVHS centers may not be read by a radiologist in time for an appointment. The result is that the clinic pulmonologist often must base decisions on a CT reading, but without the assistance of high-fidelity computer programs or a high-definition scan.5 These limitations indicate why it is important to know whether assessment by a pulmonologist compares favorably with assessment by a radiologist and with the eventual diagnosis.
The malignancy rate in the referred population is not insignificant. Halbert and colleagues found a 25% malignancy rate in their study,12 and the present study had an overall malignancy rate of 54%. The difference may be attributed to the possibility that the patients may have been prescreened prior to referral.
The reviewers overestimated the presence of malignant disease, though not to a level of statistical significance. About 88% of cases evaluated by a pulmonologist and 83% of cases evaluated by a radiologist were confirmed to be malignant. The reviewers’ sensitivity was perfect for all diagnoses except benign neoplasms, likely because these cases were classified malignant, thus increasing sensitivity but decreasing specificity.
This dynamic is important to understand, as it allows for a very high negative predictive value, which has real implications for resource management at VA hospitals, including CAVHS facility, where almost every CT scan with an abnormality is referred for pulmonologist consultation. In these cases, the radiologist not only lists the likely suspicion but includes a recommendation for follow-up or further workup based on Fleischner Society guidelines.4,14 The patient should be informed of findings as soon as the radiologist reads the CT scan, and a plan should be made on the basis of the recommendation. The patient should not have to unnecessarily wait—a potential source of anxiety—to see another specialist who would probably make the same recommendation.
Applying this study’s findings could improve workflow and the timing of CT scans. A patient should not be referred to a pulmonologist unless specifically recommended by a radiologist, thus decreasing the scheduling burden on the specialty clinic and allowing for appropriate patients to be scheduled at reasonable intervals. In addition, having only 1 person in charge of ordering CT scans could reduce the chance of duplicating orders and performing CT scans at inappropriate times.
Most important, these results should lead to more detailed physician–patient discussions about radiologic findings, hopefully alleviating any patient anxiety. A patient who still wants to see a specialist may, but with less stress that can accompany being told that there is “something abnormal” on the imaging and that the patient needs to see a lung doctor.
Limitations
This study had a few weaknesses. It was a small trial, and its data were collected retrospectively. In addition, generalizing its results may be difficult, as its reviewers had less than 5 years of training, and reviewers with more experience likely would be more accurate and have a higher rate of agreement.