Accuracy of helical computed tomography for the identification of lymph node metastasis in resectable non-small cell lung cancer.

Purpose: The criteria for the diagnosis of lymph node metastasis (LNM) in non-small cell lung cancer were investigated using helical computed tomography (hCT). The conventional criterion (1-cm short axis threshold) is generally accepted; however, this criterion is based on conventional CT. New criteria for LNM were investigated because the resolution of hCT is better than that of conventional CT.
Methods: Ninety-seven NSCLC patients examined with hCT were enrolled. Both the long axis (LA) and short axis (SA) of the nodes were measured using hCT.
Results: Based on the receiver operating characteristic curves, the thresholds that gave optimal sensitivity and specificity for LNM were 13 mm for LA and 9 mm for SA. The LNM diagnosis was re-evaluated using the combination of cutoff values. When the LA was > or =13 mm and the SA was > or =9 mm, the sensitivity, specificity, and accuracy were 56.3%, 92.1%, and 88.1%, respectively. When the LA was > or =13 mm or SA was > or =9 mm, sensitivity, specificity, and accuracy were 75.0%, 74.7%, and 74.7%, respectively. These values were not so different from the conventional criterion recalculated from these data.
Conclusion: The new criteria are considered to be useful for making a LNM diagnosis. The conventional criteria for the LNM diagnosis might therefore be applicable even for hCT.