Clinical features and prognostic factor of small (≤2 cm) lung cancer associated with cystic airspaces

Lung cancer associated with cystic airspaces (LCCA) is an uncommon subtype of lung cancer in which cystic lesions are present within or adjacent to the tumor. Despite advances in computed tomography (CT) screening, early diagnosis remains challenging, and radiologic tumor size is often underestimated. This study aimed to evaluate surgical cases of LCCA with radiologic tumor diameter ≤2 cm and to clarify their clinicopathological characteristics and prognostic impact.

Among 606 patients who underwent surgical resection for primary lung cancer between 2017 and 2020, 299 had radiologic tumor diameters ≤2 cm. These patients were classified into an LCCA group (n=26) and a non-LCCA group (n=273). Clinicopathological characteristics, radiologic-pathologic tumor size discrepancies, and survival outcomes were compared. Prognostic factors were analyzed using the Cox proportional hazards model, and disease-free survival (DFS) and overall survival (OS) were evaluated using Kaplan-Meier analysis.

Preoperative carcinoembryonic antigen (CEA) levels were significantly higher in the LCCA group compared with the non-LCCA group (6.13 vs. 4.71 ng/mL). Univariate analysis identified sex, smoking history, CEA level, and LCCA as prognostic factors, while multivariate analysis demonstrated LCCA as the only independent predictor of poor prognosis. Both DFS and OS were significantly worse in the LCCA group. The mean radiologic tumor diameter in LCCA was 1.5 cm, whereas the mean pathological diameter was 2.53 cm, indicating an approximate 1 cm underestimation on preoperative imaging.

In small lung cancers, LCCA is associated with poorer prognosis and substantial radiologic-pathologic size discrepancy. These findings highlight the need for careful surgical decision making, as radiologic measurements may underestimate true tumor extent in LCCA.