Evaluation of the effects of chemotherapy in lung cancer by thoracic computed tomography

In thoracic-computed tomography (CT) before and after chemotherapy against lung cancer in 23 patients, the percentages of the reduction of tumor size were calculated by three different methods of measurements, including (1) the product of the largest perpendicular diameter of the tumor, (2) the area of the tumor determined by the tracing method on the image which has the largest tumor mass visualized, and (3) the sum of the areas of all tumors measured by the tracing method. The tumor reduction percentages measured by these three different methods showed good correlation (1 versus 2, 2 versus 3, 3 versus 1; P less than 0.001). Therefore, it was assumed that the percentage of tumor reduction determined by the thoracic CT can be calculated correctly by the product of the perpendicular diameters of tumors on the selection of the image which has the largest tumor mass visualized.