Prognostic Classification of Multiple Primary Lung Cancers Based on a Ground-Glass Opacity Component

Abstract

We evaluated the prognostic impact of the presence of a ground-glass opacity (GGO) component on thin-section computed tomography for the refined clinical T classification of multiple primary lung cancers. We reviewed 272 surgically resected, clinically node-negative multiple lung cancers. Dominant tumors were classified into 2 groups based on the presence of a GGO component; that is, a GGO tumor (consolidation tumor ratio, 0 to <1.0) or pure-solid (PS) tumor (consolidation tumor ratio, 1.0). Furthermore, multifocal GGOs (MFGGOs) were defined as lesions showing a GGO component for all tumors. Their prognoses were evaluated using Cox proportional hazard model. There were 153 MFGGOs (56%) with a significantly better 5-year overall survival than non-MFGGOs (97.2% vs 68.5%, P < .001). A multivariable analysis revealed that MFGGO and absence of nodal involvement were independently significant prognosticators of better survival (P= .007 and P= .012, respectively). Furthermore, among the patients of non-MFGGO groups, multivariate analysis showed that a PS+ PS pattern and presence of nodal involvement were independently significant prognosticators of poorer survival (P= .008 and P= .001, respectively). We divided the tumors into 3 groups based on the results and focusing on the presence of a GGO; that is, MFGGO (n= 153), PS+ additional GGO (n= 81), and PS+ PS (n= 38). The 5-year overall survival was clearly split among them: MFGGO, 97.2%; PS+ additional GGO, 82.1%; and PS+ PS, 41.3% (P < .001). Our results suggest that presence of a GGO component has the ability to distinguish the survival even for multiple lung cancers. Further investigations including multicenter trials are certainly warranted to address the revision of T variable of multiple lung cancers considering a presence of GGO component.