Clinicopathologic features of resected subcentimeter lung cancer

Subcentimeter lung cancers are still rare, and their pathobiologic behavior and management have not yet been fully clarified.

From 1993 through 2011, 291 patients with resected lung cancers 1.0 cm or less in diameter were studied regarding their clinicopathologic characteristics. According to appearance on high-resolution computed tomography (HRCT), the tumors were classified into four types: type 1 (n = 50), nonsolid ground-glass opacity (GGO) lesion; type 2 (n = 89), part-solid GGO lesion including 50% or more GGO within the lesion; type 3 (n = 62), part-solid GGO lesion including less than 50% GGO within the lesion, and type 4 (n = 90), solid lesion.

Although none of types 1 to 3 tumors had lymph node metastases, these were found in 10% of type 4 tumors. Recurrence was observed in 13 patients, almost all of whom had type 4 tumors. The lone exception was a patient with a type 3 tumor in whom local recurrence developed on a surgical staple line. The 5-year overall survival rates were 100% in type 1 and type 2, 98% in type 3, and 88% in type 4. Type 4 had a significantly worse prognosis than the other types.

Subcentimeter lung cancers with a GGO component on HRCT (types 1 to 3) can be considered "early" lung cancers. In these cases, limited resection may be warranted to achieve a cure because they had no lymph node metastasis. By contrast, lobectomy should still be considered the standard operation of choice for type 4 tumors.