Purpose: To assess the vascular component of small lung cancers.
Material and methods: We identified 105 resected non-small-cell lung carcinomas without pathologic evidence of vascular, lymphatic, bronchial, or pleural invasion. The percentage of BAC (% BAC) of all adenocarcinomas was determined by a pulmonary pathologist. A representative histology slide of each carcinoma was digitally scanned and the number of blood vessels (#V) with at least a diameter of 200microm was identified as well as the area of these blood vessels (VA) and of the tumor (TA) was obtained. The CT consistency of the cancers was also recorded as non-solid (NS), part-solid (PS) and solid.
Results: The number of blood vessels per cm(2) of tumor area (#V/TA) was higher for adenocarcinoma (7.3+/-4.7) as compared with large- and squamous-cell carcinoma (3.6+/-2.1, 2.3+/-1.1, respectively, P<0.0001). For adenocarcinoma, #V/TA decreased with decreasing % BAC from 10.3 vessels per cm(2) of tumor area for 100% BAC to 5.1 vessels per cm(2) of tumor area for 0% BAC. The ratio of the total vascular area to tumor area (VA/TA), however, did not differ significantly by cell type nor for the adenocarcinoma by % BAC (P=0.87). While #V/TA decreased from 9.6 for non-solid nodules, to 7.5 for part-solid nodules and to 5.1 for solid nodules, there was no significant difference (P=0.27) in the VA/TA ratio by nodule consistency. Overall, VA comprised 2.7% of the total tumor area (TA) for 105 cancers.
Conclusions: These results suggest that tumor vessels experience a continuous temporal and spatial remodeling as tumors grow and that bigger tumors tend to have fewer but larger blood vessels. It also suggests that, on average, squamous- or large-cell carcinomas have a larger average vessel diameter as compared with adenocarcinomas and that the vasculature of an adenocarcinoma might remodel as the % BAC decreases. The overall proportion of tumor volume comprised of vessels 200microm or larger is small and unlikely to influence overall tumor volume and doubling time estimates.
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