Should mediastinal nodal dissection be routinely undertaken in patients with peripheral small-sized (2 cm or less) lung cancer? Retrospective analysis of 225 patients.

OBJECTIVE

We retrospectively reviewed nodal status of the patients with peripheral small-sized lung cancer grouped by cell type and tumor size to evaluate the necessity of systematic nodal dissection in this group of patients.

METHODS

From 1973 to 1998, 1713 patients underwent pulmonary resection for primary lung cancer in Kanazawa University. Among them, 225 patients (13.1%) with peripheral small-sized (2 cm or less) lung cancer underwent lobectomy and systematic nodal dissection were retrospectively reviewed. The maximum diameter of the tumor was measured on formalin-fixed surgical specimens.

RESULTS

The histological types were adenocarcinoma in 170 (75.6%), squamous cell carcinoma in 20 (8.9%), small cell carcinoma in 19 (8.4%) and others in 16 (7.1%). Among 170 adenocarcinoma patients, 38 (22.4%) showed hilar or mediastinal lymph node metastases. No mediastinal lymph node metastasis was encountered in all squamous cell carcinoma (n = 20), adenocarcinoma < or = 1 cm (n = 16), small cell carcinoma < or = 1 cm (n = 4), and adenocarcinoma of Noguchi's classification type A or B (n = 24).

CONCLUSIONS

Mediastinal nodal dissection would be unnecessary in the patients with peripheral small-sized lung cancer fulfilling these criteria: (1) squamous cell carcinoma < or = 2 cm; (2) adenocarcinoma < or = 1 cm; (3) localized bronchioloalveolar carcinoma < or = 2 cm without foci of active fibroblastic proliferation in histology (Noguchi's classification type A or B adenocarcinoma); (4) small cell carcinoma < or = 1 cm. Candidates fulfilling above criteria were 28.4% (64/225) of small-sized lung cancer and 10.9% of stage IA patients. The establishment of a universally accepted therapeutic strategy for small-sized lung cancer is indispensable in the clinical spread of various sort of limited resections.