Meta-Analysis of Association between CT-based Features and Tumor Spread Through Air Spaces in Lung Adenocarcinoma

Abstract

Objective：Spread through air space (STAS) is a novel invasive pattern of lung adenocarcinoma and is also a risk factor for recurrence and worse prognosis of lung adenocarcinoma after sublobar resection. The aims of this study are to evaluate the association between computed tomography (CT)-based features and STAS for preoperative prediction of STAS in lung adenocarcinoma, eventually, which could help us choose appropriate surgical type. Methods：Systematic research was conducted to search for studies published before September 1, 2019. The association between CT-based features of radiological tumor size＞2cm、pure solid nodule、 part-solid nodule or Percentage of solid component(PSC)＞50% and STAS was evaluated. According to rigorous inclusion and exclusion criteria. Eight studies including 2,385 patients published between 2015 and 2018 were finally enrolled in our meta-analysis.Results：Our results clearly depicted that there is no significant relationship between radiological tumor size＞2cm and STAS with the combined OR of 1.47(95% CI:0.86-2.51). Meta-analysis of 3 studies showed that pure solid nodule in CT image were more likely to spread through air spaces with pooled OR of 3.10(95%CI2.17-4.43). Meta-analysis of 5 studies revealed the part-solid nodule in CT image may be more likely to appear STAS in adenocarcinoma (ADC) (combined OR:3.10,95%CI:2.17-4.43). PSC＞50% in CT image was a significant independent predictor in the diagnosis of STAS in ADC from our meta-analysis with combined OR of 2.95(95%CI:1.88-4.63).Conclusion：In conclusion, The CT-based features of pure solid nodule、part-solid nodule、PSC＞50% are promising imaging biomarkers for predicting STAS in ADC and may substantially influence the choice of surgical type. In future, more studies with well-designed and large-scale are needed to confirm the conclusion.

The prognostic significance of tumor spread through air space in stage I lung adenocarcinoma

“…In previous literature, STAS was found to be associated with aggressive clinicopathologic characteristics in surgically resected lung ADC 29 . In imaging finding, STAS is associated with higher pathological stage, a larger tumor diameter, higher presence of solid component, and vascular convergence 30,31 . In terms of pathology finding, STAS was strongly linked to the presence of lymphovascular invasion and high‐grade morphologic patterns, including larger nuclear size, increased mitotic count, and high Ki‐67 labeling index, which suggests that STAS can serve as a marker for tumor proliferation 29,32 .…”

“…29 In imaging finding, STAS is associated with higher pathological stage, a larger tumor diameter, higher presence of solid component, and vascular convergence. 30,31 In terms of pathology finding, STAS was strongly linked to the presence of lymphovascular invasion and high-grade morphologic patterns, including larger nuclear size, increased mitotic count, and high Ki-67 labeling index, which suggests that STAS can serve as a marker for tumor proliferation. 29,32 Chen et al carried out a multi-institutional study to investigate whether stage I ADC with STAS can benefit from adjuvant chemotherapy.…”

Computed Tomography Features and Tumor Spread Through Air Spaces in Lung Adenocarcinoma

“…While the previous meta-analysis by Yin et al had included studies that reported on this association, they did not strictly include studies that used CT imaging. 24 There were studies that were based solely on histopathology examination. However, in the current meta-analysis, only those studies that used CT-based radiologic investigation were included.…”

“…To the best of our knowledge, the current meta-analysis provides the most updated data on the association between STAS and CT-based features in patients with lung adenocarcinoma. While the previous meta-analysis by Yin et al had included studies that reported on this association, they did not strictly include studies that used CT imaging 24. There were studies that were based solely on histopathology examination.…”

“…6,23 Novel state-of-the-art multidetector CT scanners are now capable of providing finer details of the tumor morphology and the extent of invasion to adjacent tissues. 23 In a recent meta-analysis, Yin et al 24 evaluated CT-based features of lung adenocarcinoma and reported only 5 studies that had utilized CT imaging. The results indicated that the presence of pure solid nodules and part-solid nodules on CT imaging was associated with the increased risk of STAS positivity.…”