[Relationship between Noguchi's classification for small adenocarcinomas of the lung and tumor markers in serum]

We evaluated the relationship between Noguchi's classification for small adenocarcinomas of the lung and tumor markers in serum (CEA, Cyfra, SLX, CA 19-9, CA 125). Fifty surgically resected small peripheral adenocarcinomas measuring 2 cm or less in greatest diameter were examined. The tumors were divided into three groups on the basis of Noguchi's classification: group AB of tumors belonging to Noguchi's classification A or B, group C of tumors belonging to Noguchi's classification C, and group DEF of tumors belonging to Noguchi's classification D, E, or F. The level of serum CEA was higher in group DEF (5.9 +/- 7.6 ng/ml) than in group AB (2.3 +/- 2.4 ng/ml) and group C (2.0 +/- 1.3 ng/ml). There were no differences in the levels of the other serum tumor markers among the three groups. The incidences of anormality in serum CEA and Cyfra were higher in group DEF (6/18 and 6/18, respectively) than in group AB (1/7 and 0/7) and group C (1/25 and 1/25). Although a high level of serum CEA or Cyfra is a strong indication that the tumor is Noguchi's classification D, E, or F of pulmonary adenocarcinoma, it is difficult to classify small adenocarcinomas by Noguchi's classification using a serum tumor marker level.