Can autoantibody tests enhance lung cancer screening?—an evaluation of EarlyCDT®-Lung in context of the German Lung Cancer Screening Intervention Trial (LUSI)

Background: Tumor-associated autoantibodies are considered promising markers for early lung cancer detection; so far, however, their capacity to detect cancer has been tested mostly in a clinical context, but not in population screening settings. This study evaluates the early detection accuracy, in terms of sensitivity and specificity, of EarlyCDT®-Lung—a test panel of seven tumor-associated autoantibodies optimized for lung cancer detection—using blood samples originally collected as part of the German Lung Cancer Screening Intervention Trial. Methods: The EarlyCDT®-Lung test was performed for all participants with lung cancer detected via low-dose computed tomography and with available blood samples taken at detection, and for 180 retrospectively selected cancer-free participants at the end of follow-up: 90 randomly selected from among all cancer-free participants (baseline controls) and 90 randomly selected from among cancer-free participants with suspicious imaging findings (suspicious nodules controls). Sensitivity and specificity of lung cancer detection were estimated in the case group and the two control groups, respectively. Results: In the case group, the test panel showed a sensitivity of only 13.0% (95% CI: 4.9–26.3%). Specificity was estimated at 88.9% (95% CI: 80.5–94.5%) in the baseline control group, and 91.1% (95% CI: 83.2–96.1%) among controls presenting CT-detected nodules. Conclusions: The test panel showed insufficient sensitivity for detecting lung cancer at an equally early stage as with low-dose computed tomography screening.