Prognostic significance of ground-glass areas within tumors in non-small cell lung cancer

To validate or refute the hypothesis that non-small cell lung cancers (NSCLC) with ground-glass areas (GGA+) within the tumor on high-resolution computed tomography (HRCT) are associated with a more favorable prognosis than those without GGA (GGA-).We analyzed data from a multicenter observational cohort study in Japan including 5,005 patients with completely resected pathological stage I NSCLC, who were excluded from the Japan Clinical Oncology Group (JCOG) 0707 trial on oral adjuvant treatment during the enrollment period. The patients' medical and pathological records were assessed retrospectively by physicians and re-staged according to the 8th tumor, node, metastasis (TNM) edition.Of the 5,005 patients, 2,388 (48%) were ineligible for the JCOG0707 trial and 2,617 (52%) were eligible but were not enrolled. A total of 958 patients (19.1%) died. Patients with GGA+ NSCLC and pathological invasion ≤ 3 cm showed significantly better overall survival than others. In patients with tumors with an invasive portion ≤ 4 cm, GGA+ was associated with better survival. The prognoses of patients with GGA+ T2a and GGA- T1c tumors were similar (5-year overall survival: 84.6% versus 83.1%, respectively). The survival with T2b or more tumors appeared unaffected by GGA, and GGA was not prognostic in these larger tumors.Patients with GGA+ NSCLC on HRCT and ≤ 4 cm invasion size may have a better prognosis than patients with solid GGA- tumors of the same T-stage. However, the presence or absence of radiological GGA has little impact on the prognosis of patients with NSCLC with greater (> 4 cm) pathological invasion.