Purpose: Noguchi and colleagues reported that the growth pattern of small-sized adenocarcinoma was related to the vascular involvement and the prognosis of the patient. Noguchi's type A/B tumors had no lymph node metastasis, rare vascular involvement, and an excellent prognosis, which meant that Noguchi's type A/B tumors were preinvasive tumors of the peripheral type. Although Noguchi's classification was usually determined based on resected specimens, it would be useful to make a decision about the therapeutic strategy if the classification could be determined preoperatively based on the fluorodeoxyglucose (FDG) uptake.
Methods: The FDG uptake in 61 pulmonary adenocarcinomas measuring 3 cm or smaller in diameter was compared with the mediastinal uptake and was classified into five grades. The relationship between the FDG uptake and Noguchi's classification (A to F) was analyzed.
Results: The FDG uptake was significantly lower in Noguchi's type A/B tumors than in type C or in type D/E/F. Eleven of 12 tumors (92%) with no increased or a weak FDG uptake were classified as type A/B, whereas 32 of 33 tumors (97%) with a strong or very strong FDG uptake were classified as type C-F.
Conclusions: The FDG uptake is helpful for making an accurate diagnosis of Noguchi's classification preoperatively in patients with pulmonary adenocarcinoma.