An analytic study of small lung cancers

Where should the border-line of early peripheral lung cancer be drawn?

Abstract

The definition of early lung cancer remains controversial as to whether the maximal diameter should be less than 1.5 cm. We studied 41 patients with lung cancers with a diameter less than 3.0 cm. The patients were divided into four groups based on tumor size : group I : 0.5-1.5 cm ; group II : 1.6-2.0 cm ; group III : 2.1-2.5 cm ; group IV : 2.6-3.0 cm. The total 5-year survival rate of this series is 55.0%, that of group I, II, III, and IV is 87.8%, 56.5%, 42.0%, and 53.2%, respectively. Clearly, patients with smaller tumors have better survival rates. We also surveyed reports from 20 institutions and found that seven, including our own, reported a 5-year survival rate of 100% for patients with tumors smaller than 1.5 cm without lymph node metastasis. Thus it is reasonable to define early lung cancer as a NoMo tumor less than 1.5 cm in diameter. However, their survival rates of less than 80% were also reported, and numerous patients (23.7%) had lymph node metastases. Thus, it seems more appropriate to draw the border-line of the diameter of “peripheral early lung cancer” with a tumor size of less than 1.0 cm, since this level shows the least metastasis (12.5%) to lymph nodes in the present time.