Lung Adenocarcinomas Manifesting as Radiological Part-Solid Nodules Define a Special Clinical Subtype

Abstract

Introduction: The clinicopathologic features and prognostic predictors of radiological part-solid lung adenocarcinomas were unclear.

Methods: We retrospectively compared the clinicopathologic features and survival times of part-solid tumors with those of pure ground glass nodules (pGGNs) and pure solid tumors treated with surgery at Fudan University Shanghai Cancer Center and evaluated the prognostic implications of consolidation-to-tumor ratio (CTR), solid component size, and tumor size for part-solid lung adenocarcinomas.

Results: A total of 911 patients and 988 pulmonary nodules (including 329 part-solid nodules [PSNs], 501 pGGNs, and 158 pure solid nodules) were analyzed. More female patients (p = 0.015) and nonsmokers (p = 0.003) were seen with PSNs than with pure solid nodules. The prevalence of lymphatic metastasis was lower in patients with PSNs than in those with pure solid tumors (2.2% versus 27% [p < 0.001]). The 5-year lung cancer-specific (LCS) recurrence-free survival and LCS overall survival of patients with PSNs were worse than those of patients with pGGNs (p < 0.001 and p = .042, respectively) but better than those of patients with pure solid tumors ([p < 0.001 and p < 0.0001, respectively]). CTR (OR = 12.90; 95% confidence interval [CI]: 1.85-90.04), solid component size (OR = 1.45; 95% CI: 1.28-1.64), and tumor size (OR = 1.23; 95% CI: 1.15-1.31) could predict pathologic invasive adenocarcinoma for patients with PSNs. None of them could predict the prognosis. Patients receiving sublobar resection had prognoses comparable to those of patients receiving lobectomy (p = .178 for 5-year LCS recurrence-free survival and p = .319 for 5-year LCS overall survival). The prognostic differences between patients with systemic lymph node dissection and those without systemic lymph node dissection were statistically insignificant.

Conclusions: Part-solid lung adenocarcinoma showed clinicopathologic features different from those of pure solid tumor. CTR, solid component size, and tumor size could not predict the prognosis. Part-solid lung adenocarcinomas define one special clinical subtype.

Keywords: Lung adenocarcinoma; Part-solid nodule; Prognosis; Solid component size; Tumor size.