Evolution of peripheral lung adenocarcinomas: CT findings correlated with histology and tumor doubling time

Peripheral lung adenocarcinoma: correlation of thin-section CT findings with histologic prognostic factors and survival

PURPOSE

To evaluate the prognostic importance of thin-section computed tomographic (CT) findings of peripheral lung adenocarcinomas.

MATERIALS AND METHODS

The subjects were 127 patients with adenocarcinomas smaller than 3 cm in largest diameter who underwent at least a lobectomy with hilar and mediastinal lymphadenectomy. The margin characteristics of nodules and the extent of ground-glass opacity (GGO) within the nodules at preoperative thin-section CT were analyzed retrospectively. Regional lymph node metastasis (LNM) and vessel invasion (VI) were histologically examined in surgical specimens. Survival curves were calculated according to the Kaplan-Meier method.

RESULTS

The frequencies of LNM (4% [1 of 24]) and VI (13% [three of 24]) in adenocarcinomas with GGO components of more than 50% were significantly lower than those with GGO components of less than 10% (LNM, P <.05; VI, P <.01). The patients with GGO components of more than 50% showed a significantly better prognosis than those with GGO components less than 50% (P <.05). All 17 adenocarcinomas smaller than 2 cm with GGO components of more than 50% were free of LNM and VI, and all these patients are alive without recurrence. Coarse spiculation and thickening of bronchovascular bundles around the tumors were observed more frequently in tumors with LNM or VI than in those without LNM or VI (P <.01).

CONCLUSION

Thin-section CT findings of peripheral lung adenocarcinomas correlate well with histologic prognostic factors.

High-resolution CT analysis of small peripheral lung adenocarcinomas revealed on screening helical CT

OBJECTIVE

The purpose of this study was to determine the correlation between high-resolution CT morphologic features of small peripheral lung adenocarcinomas and tumor growth patterns.

MATERIALS AND METHODS

We examined high-resolution CT morphologic features of 59 small, surgically resected peripheral lung adenocarcinomas (diameter, 6-20 mm) that were detected on screening for lung cancer using low-dose helical CT. Among these adenocarcinomas, 14 (24%) were visible and 45 (76%) were invisible on conventional chest radiography. The correlation between high-resolution CT morphologic features and tumor growth patterns was analyzed.

RESULTS

Sixteen (94%) of 17 type A (Noguchi's classification) adenocarcinomas appeared as nodules of pure ground-glass attenuation (high-resolution CT type I). Ten (71%) of 14 type B tumors appeared as heterogeneous, low-attenuation nodules (type II). Seven (29%) of 24 type C tumors appeared as nodules with ground-glass attenuation in the periphery and a high-density central zone (type III), and 12 (50%) of 24 type C tumors appeared as homogeneous nodules with soft-tissue density (type IV). Among tumors with a replacement growth pattern, the size and CT values of type C tumors were larger than those of type A or type B tumors (p < 0.05), whereas the percentage of ground-glass attenuation and retained air space in type C tumors was smaller than those in type A or type B tumors (p < 0.01). All (100%) four type D tumors appeared to be homogeneous nodules with soft-tissue density (type IV).

CONCLUSION

Small peripheral lung adenocarcinomas shown on CT exhibit four high-resolution CT patterns that corresponded to the histopathologic findings of different tumor growth patterns.