Yoshihisa Shimada, Hisashi Saji, Yasufumi Kato, Yujin Kudo, Junichi Maeda, Koichi Yoshida, Masaru Hagiwara, Jun Matsubayashi, Masatoshi Kakihana, Naohiro Kajiwara, Tatsuo Ohira, Norihiko Ikeda, Shimada, Yoshihisa, Saji, Hisashi, Kato, Yasufumi, Kudo, Yujin, Maeda, Junichi, Yoshida, Koichi, Hagiwara, Masaru, and Matsubayashi, Jun
Background: Microscopic vascular invasion (MVI) in patients with non-small cell lung cancer (NSCLC) has been reported to be a strong predictor of poor outcomes but it has not been a descriptor of the TNM classification. The purposes of this study were to determine whether the presence of MVI is related to a predictor of poor outcomes and to explore the degree of MVI according to tumor size.Methods: A total of 1,884 patients with stage pT1-4N0-2 NSCLC who underwent complete resection comprised the study sample. Overall survival (OS) and recurrence-free proportion were estimated using the Kaplan-Meier method. The Cox proportional hazards model was used to assess independent predictors of poor outcomes.Results: Of 1,884 patients, 1,097 (58.2%) had MVI. Multivariate analysis showed MVI was a significant independent predictor of unfavorable OS (hazard ratio, 1.666; P < .001) and recurrence (hazard ratio, 2.268; P < .001). The frequency of MVI varied according to tumor size, and in each cohort of tumor sizes ≤ 2 cm, > 2 to 3 cm, and > 3 to 5 cm, there were significant differences in survival outcome by MVI status. The proportions of patients with a 5-year recurrence-free period with tumor sizes ≤ 2 cm, > 2 to 3 cm, and > 3 to 5 cm between MVI (+) and MVI (-) were 93.0% and 72.5% (P < .001), 90.8% and 63.3% (P < .001), and 86.4% and 59.9% (P < .001), respectively.Conclusions: This study demonstrated that MVI was a strong predictor of poor outcomes and that the effect is more prominent in patients with tumor sizes ≤ 5 cm. Further analysis of survival and MVI should be collected for future revision of the TNM system. [ABSTRACT FROM AUTHOR]