Pulmonary Endogenous Fluorescence Allows the Distinction of Primary Lung Cancer from the Perilesional Lung Parenchyma

Pre-therapeutic pathological diagnosis is a crucial step of the management of pulmonary nodules suspected of being non small cell lung cancer (NSCLC), especially in the frame of currently implemented lung cancer screening programs in high-risk patients. Based on a human ex vivo model, we hypothesized that an embedded device measuring endogenous fluorescence would be able to distinguish pulmonary malignant lesions from the perilesional lung tissue.

Consecutive patients who underwent surgical resection of pulmonary lesions were included in this prospective and observational study over an 8-month period. Measurements were performed back table on surgical specimens in the operative room, both on suspicious lesions and the perilesional healthy parenchyma. Endogenous fluorescence signal was characterized according to three criteria: maximal intensity (Imax), wavelength, and shape of the signal (missing, stable, instable, photobleaching).

Ninety-six patients with 111 suspicious lesions were included. Final pathological diagnoses were: primary lung cancers (n = 60), lung metastases of extra-thoracic malignancies (n = 27) and non-tumoral lesions (n = 24). Mean Imax was significantly higher in NSCLC targeted lesions when compared to the perilesional lung parenchyma (p<0,0001) or non-tumoral lesions (p<0,0001). Similarly, photobleaching was more frequently found in NSCLC than in perilesional lung (p<0,0001), or in non-tumoral lesions (p<0,001). Respective associated wavelengths were not statistically different between perilesional lung and either primary lung cancers or non-tumoral lesions. Considering lung metastases, both mean Imax and wavelength of the targeted lesions were not different from those of the perilesional lung tissue. In contrast, photobleaching was significantly more frequently observed in the targeted lesions than in the perilesional lung (p≤0,01).

Our results demonstrate that endogenous fluorescence applied to the diagnosis of lung nodules allows distinguishing NSCLC from the surrounding healthy parenchyma and from non-tumoral lesions. Inconclusive results were found for lung metastases due to the heterogeneity of this population.