Computed tomography screening for lung cancer

A threshold of 7.0 or 8.0 mm to define positive results in the baseline round of computed tomography (CT) screening for lung cancer could decrease further work-up and a delay in diagnosis in some patients. Although nodule size is important, it is not the sole predictor of risk for cancer. In our experience, 70% of the pleural surface is accessible by transthoracic ultrasonography when lung comes up to the pleura or is reachable via a sound window. Contrast-enhanced ultrasonography provides further information. In patients with lung cancer we observed intralesional enhancement consistent with tumor neovascularization on contrast-enhanced ultrasonography. Some cases had unenhanced areas consistent with zones of necrosis, and these areas were avoided during Fine-Needle Aspiration Biopsy (FNAB) . Thoracic ultrasonographic elastography (MyLab-ElaXto Biomedica, Genoa, Italy) is a novel approach useful to estimate the stiffness/elasticity of tissues, allowing a reliable preliminary differentiation between cancerous and noncancerous consolidations. It is followed by a focused and guided FNAB to diagnose and stage lung cancer. Thoracic ultrasonographic elastography and FNAB were performed after chest radiography and CT in 91 patients (67 men and 24 women, years 62.84±7.51) with lung consolidation. Tissue stiffness was scored from 1 (greatest elasticity) to 5 (no elasticity) using a convex multifrequency 2-8 mHz probe. Elasticity of nodules was significantly lower (P < 0.001) in all patients with lung cancer (n = 67; 4.19±0.55) than in those with pneumonitis (n= 24; 2.35±0.48 ). The size of consolidation is larger in pneumonitis vs. lung cancer (cm. 4.03±0.82 vs. 3.06±0.88; p <0.001), which is a further argument against using nodule size as a discriminant between cancerous and noncancerous consolidations. Although neither transthoracic ultrasound approach (nor CT) is widely valuated for this use, either ultrasound approach could contribute to a more efficient work-up, at least in some patients. Both ultrasound procedures provide diagnostically useful information on peripheral lung lesions and increase the diagnostic yield of transthoracic FNAB by reducing the risk for inadequate tissue sampling.