BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.