Biomarkers suitable for early detection of intrathoracic cancers in primary care: a systematic review.

Intrathoracic cancers, including lung cancer, mesothelioma, and thymoma, present diagnostic challenges in primary care. Biomarkers could resolve some challenges. We synthesized evidence on biomarkers performance for intrathoracic cancer detection in low-prevalence settings. A search in EMBASE and MEDLINE included studies that recruited participants with suspected intrathoracic cancer and reported on at least one diagnostic measure for a validated, non-invasive biomarker. Studies were excluded if participants were recruited based on a pre-established diagnosis. Fifty-two studies were included, reporting on 108 individual biomarkers and panels. CEA, CYFRA 21.1, and VEGF were evaluated for lung cancer and mesothelioma. For lung cancer, CEA and CYFRA 21.1 were most studied, with AUCs of 0.48-0.90 and 0.48-0.83, respectively. Pro-GRP and NSE had the highest NPVs (98.2%, 96.9%), while Early-CDT and MSC panels showed NPVs of 99.3% and 99.0% in smokers. For mesothelioma, Fibrillin-3 and mesothelin plus osteopontin had AUCs of 0.93 and 0.91, respectively. Thymoma panels (Binding AcHR + StrAb) and (Binding AcHR + Modulating AcHR + StrAb) had 100% NPVs in myasthenia gravis patients. The review highlights the performance of some biomarkers. However, few were evaluated in low-prevalence settings. Further evaluation is necessary before implementing these biomarkers for intrathoracic cancers in primary care.