A systematic review and meta-analysis of the influence of STAS on the long-term prognosis of stage I lung adenocarcinoma

BACKGROUND: The appearance of airway dissemination often indicates poor prognosis of lung cancer. However, the relationship between airway dissemination and early lung adenocarcinoma is not clear. Therefore, this study uses meta-analysis to study the long-term prognosis of patients with early lung adenocarcinoma. METHODS: A computer search of the PubMed, EMbase, Web of Science, and other databases was conducted, and the search time limit was from the establishment of the database to December 30, 2020. Data strictly in accordance with the inclusion and exclusion criteria was extracted and the quality of the included literature was evaluated. Two reviewers then independently screened the literature and evaluated the risk of bias. RESULTS: A total of 11 studies were included, comprised of 5,097 patients with early lung adenocarcinoma. The results of the meta-analysis showed that among patients with stage I lung adenocarcinoma, the 5-year recurrence-free survival (RFS) and overall survival (OS) of STAS-positive patients was lower than those of the STAS-negative group, and the difference was statistically significant. In the control study, the 5-year RFS was HR =1.95, 95% CI (1.58–2.31) P<0.01, and the 5-year OS was OR =2.04, 95% CI (1.60–2.48) P<0.01, and in STAS-positive patients, sublobectomy had a worse long-term prognosis than lobectomy. While the 5-year RFS HR of the lobectomy group was 1.82, 95% CI (1.43–2.22), and the 5-year RFS HR of the sublobectomy group was 6.92, 95% CI (1.64–12.18) P<0.01, the prognosis of the STAS-positive high-expression group and the low-expression group was worse. The 5-year RFS HR of the low-expression STAS group was 2.93, 95% CI (0.21–6.07), and in the high expression group this was 8.20, 95% CI (0.55–15.85) P<0.05. DISCUSSION: STAS is an independent risk factor for the poor prognosis of stage I lung adenocarcinoma and a high expression of STAS results in a higher 5-year recurrence rate. When STAS is positive, the sublobectomy method should be carefully selected. However, our research has certain limitations, such as literature selection and publication bias. At the same time, the depth of literature analysis needs to be further improved.