The correlation between tumor radiological features and spread through air spaces in peripheral stage IA lung adenocarcinoma: a propensity score-matched analysis

Abstract

Background: The consolidation tumor ratio (CTR) is a predictor of invasiveness in peripheral T1N0M0 lung adenocarcinoma. However, its association with spread through air spaces (STAS) remains largely unexplored. We aimed to explore the correlation between the CTR of primary tumors and STAS in peripheral T1N0M0 lung adenocarcinoma.

Methods: We collected data from patients who underwent surgery for malignant lung neoplasms between January and November 2022. Univariate and multivariate analyses following propensity-score matching with sex, age, BMI, were performed to identify the independent risk factors for STAS. The incidence of STAS was compared based on pulmonary nodule type. A smooth fitting curve between CTR and STAS was produced by the generalized additive model (GAM) and a multiple regression model was established using CTR and STAS to determine the dose-response relationship and calculate the odds ratio (OR) and 95% confidence interval (CI).

Results: 17 (14.5%) were diagnosed with STAS. The univariate analysis demonstrated that the history of the diabetes, size of solid components, spiculation, pleural indentation, pulmonary nodule type, consolidation/tumor ratio of the primary tumor were statistically significant between the STAS-positive and STAS-negative groups following propensity-score matching(p = 0.047, 0.049, 0.030, 0.006, 0.026, and < 0.001, respectively), and multivariate analysis showed that the pleural indentation was independent risk factors for STAS (with p-value and 95% CI of 0.043, (8.543-68.222)). Moreover, the incidence of STAS in the partially solid nodule was significantly different from that in the solid nodule and ground-glass nodule (Pearson Chi-Square = 7.49, p = 0.024). Finally, the smooth fitting curve showed that CTR tended to be linearly associated with STAS by GAM, and the multivariate regression model based on CTR showed an OR value of 1.24 and a p-value of 0.015.

Conclusions: In peripheral stage IA lung adenocarcinoma, the risk of STAS was increased with the solid component of the primary tumor. The pleural indentation of the primary tumor could be used as a predictor in evaluating the risk of the STAS.

Keywords: Adenocarcinoma; Consolidation tumor ratio; Odds ratio; Tumor spread through air spaces.

Fig. 1

a shows a female patient aged 58 with a solid nodule in the lower lobe of the left lung, as seen on CT scan with a maximum diameter of 2.4 cm (indicated by the white arrow). The nodule has a CTR of 1. Similarly, in b, a male patient aged 61 is shown to have a partially solid nodule in the upper lobe of the right lung, with a solid component size of 0.6 cm (indicated by the white arrowhead) and a maximum diameter of 1.3 cm (indicated by the white arrow). The CTR for this lesion is 0.6/1.3 = 0.46

Fig. 2

Flow chart of the population selection

Fig. 3

Different types of nodules and microscopic pathological findings. a, b Male, 64, a shows an axial CT of the lung window lesion located in a solid pulmonary nodule in the left lower lobe, with a maximum diameter of 2.5 cm. b shows a 100x pathological microscopic image of invasive adenocarcinoma with more dissemination in the STAS. c, d Male, 61, c shows a CT axial lung window lesion located in a ground glass pulmonary nodule in the upper lobe of the right lung, with a tumor length of 1.5 cm. d shows a 100x pathological microscopic image of invasive adenocarcinoma with less dissemination in the STAS. e, f Male, 61. e shows a CT axial view of the lung window lesion located in a partial solid pulmonary nodule in the right upper lobe, with a CTR of 0.46. f shows a 100x pathological microscopic image of invasive adenocarcinoma with more dissemination in the STAS

Fig. 4

The smooth fitting curve between the CTR of the primary tumor and STAS. The smooth fitting curve showed that CTR tended to be linearly associated with STAS after adjusting for sex, age, BMI. The X-abscissa represented the CTR value, and the Y-ordinate represented the risk of primary tumor STAS. The solid black line represented CTR was linearly associated with STAS, and the black dotted lines above and below represent the 95% CI