[Significance of lymph nodes dissection of lung cancer treatment]

From 1950 to 1991, 1,221 lung cancer cases were treated with surgery in Tokyo Medical College Hospital. The 5-year survival rate was achieved in 70.1% for stage I, 49.5% for stage II, 17.0% for stage III A, 0% for stage III B and 8.3% for stage IV respectively. Considering for the survival rate with pN factor in 753 resected cases, the 5-year survival rate of N0, N1, N2 and N3 cases was 65.8%, 38.1%, 16.3% and 0% respectively. In these pN2 group, the 5-year survival rate of single mediastinal lymph node metastasis cases was 35.5%, while that of multiple mediastinal lymph node metastasized cases was 6.9%. The relationship between lymph node metastasis and DNA ploidy pattern was also discussed. The most of N0 cases showed diploid pattern, while N2 cases indicated aneuploid pattern. A mediastinal lymph node dissection of pN2 lung cancer cases may be effective to improve the prognosis of a kind of cases showing biologically low malignant lung cancer.