Abstract
In 338 cases of surgically resected primary lung cancer from 1979 to 1984, preoperative evaluation of the T-factor and N-factor was performed in 2 groups, that is, one undergoing CT examination (CT (+)), the other was without CT examination (CT (-)).
The accuracy of the T-factor was 83.3% for the p-T1 cases, 73.2% for the p-T2 cases, 71.2% for the p-T3 cases, and 74.9% overall. In the p-T1 cases the accuracy of the CT (+) group was higher than the CT (-) group, on the contrary, in p-T2 cases the accuracy of the CT (-) was higher than the CT (+) group.
The main causes of mistaken evaluation of the T-factor were (1) error in measuring tumor diameter and (2) error in recognizing the presence or absence of invasion to adjacent organs. In the CT (+) group, there were fewer cases in which the T-factor was underestimated compared with the CT (-) group. On the other hand, there were more cases of overestimation.
The diagnostic accuracy of the N-factor was 75.5% for the p-NO cases, 41.7% for the p-N1 cases, 48.9% for the p-N2 cases, and 62.4% overall.
This was clearly inferior to the results for the T-factor.
In the CT (+) group the accuracy of evaluation of N1 was less than the CT (-) group, but that of N2 was markedly increased.
However, there were many cases overestimated because of swollen lymph nodes without metastasis in squamous cell carcinoma cases, and no improvement was noted in the diagnostic accuracy of the N-factor in the CT (+) group.
The diagnostic accuracy of the CT (+) group was not neccesarily markedly better than the CT (-) group, in terms of either the T-factor or N-factor.
