Lobe-specific skip nodal metastasis in non-small cell lung cancer patients.

PURPOSE The purpose of this study is to clarify the lobe-specific nodal metastasis and optimal range of mediastinal nodal dissection in lung cancer patients with skip metastasis. MATERIALS AND METHODS A total of 136 patients with pN2/3 disease were treated between 1988 and 2002, and these patients were divided into two groups according to whether skip metastasis was identified or not. We drew a comparison of the lobe specificity of mediastinal nodal involvement between skip positive and negative groups. RESULTS Skip metastasis was identified in 48 (35.3%) of 136 pN2/3 patients. The lymph nodal regions most frequently found (target nodes) were as follows: right upper-#3 and right #4, middle & lower-#3, right #4 and #7, left upper-left #4, #5, and #6, and left lower-#7, #8, and #9. Skip metastasis can be detected at a rate of 82.6% to 91.7% by means of a histological examination of these target nodes. However, the frequency of skip metastasis in other mediastinal nodal regions excluding the target nodes was found to progress to a level of 33.3% to 57.1% insofar as tumor metastasis to these target nodes was identified. CONCLUSIONS The examination of lobe-specific nodal regions may be helpful for determining patients with skip metastasis. If metastasis is found somewhere in these target nodes, then a systematic nodal dissection may be acceptable for a complete resection even if N1 metastasis is not identified.