Incidental Diagnosis of Asymptomatic Non-Small-Cell Lung Cancer: A Registry-Based Analysis

Clinical manifestation of non-small-cell lung cancer (NSCLC) mainly occurs at advanced stages. Thus, the scientific community is evaluating different screening programs in high-risk patients to detect NSCLC at an earlier stage to improve survival. However, up to now patient selection and modalities have been discussed controversially. In this analysis we aimed to focus on asymptomatic NSCLC patients, whose disease was detected coincidentally and to elaborate the significance and effect of incidentally detected NSCLC on survival.

Medical files of 1279 consecutive NSCLC patients diagnosed between 2001 and 2009 were retrospectively analyzed. Incidentally detected asymptomatic NSCLC patients were compared with patients with tumor-specific symptoms.

In 117 of 1279 patients an asymptomatic diagnosis was ascertained by coincidence (9.1%). A smoking history of ≥ 30 pack-years was documented in 41 (58.6%) of 70 evaluable patients with incidentally detected NSCLC. Patients with incidentally diagnosed NSCLC were characterized by lower stages at diagnosis, a better performance status, and a higher proportion of previous or present other malignancies. Overall survival (OS) was significantly superior in patients with an asymptomatic diagnosis compared with patients with symptoms (median OS, 38.9 months vs. 16.1 months; P < .001). In a Cox proportional hazard model, incidental diagnosis proved to be an independent prognostic factor with regard to OS.

Our findings point to the advantage of asymptomatic detection of NSCLC and might underline the benefit of screening programs. Further research on the detection of lung cancer in asymptomatic patients outside of existing screening criteria is warranted.