SURGICALLY CURABLE EARLY ADENOCARCINOMA IN THE PERIPHERY OF THE LUNG

To define surgically curable ''early'' adenocarcinoma in the periphery of the lung, we examined histopathologic prognostic factors in 56 cases of stage I mucinous, nonmucinous, and sclerosing bronchioloalveolar carcinomas less than 2 cm in diameter. The death rate 5 years after surgery was only 1.8%, but the recurrence rate within 5 years after surgery was 8.9%. In addition, there were two cases of recurrence more than 5 years after surgery. Vascular invasion (p < 0.05) and mitotic index (p < 0.01) were the most important determinants of prognosis, and there was no recurrence or death in cases showing grades 1 and 2 collagenization in fibrotic foci. These results indicate surgically curable stage I adenocarcinomas to be less than 2 cm in diameter and without vascular invasion, with a low mitotic index and grade 1 or 2 fibrotic scarring, although the significance of nuclear atypia as a prognostic factor remains to be clarified. It may be possible to improve the cure rate by postoperative adjuvant chemotherapy for ''early'' adenocarcinoma with vascular invasion, high mitotic index, higher scar grade, and probably a high degree of nuclear atypia.