Don’t tar them all with the same brush: different grades of visceral pleura invasion in resectable lung adenocarcinomas correlates with aggressive behavior and poor prognostic outcomes.

<bold>Introduction:</bold> Visceral pleura invasion(VPI) in lung adenocarcinoma(LUAD) is a well-known prognostic factor. The prognostic impact of different grades of VPI, namely PL1(tumor goes beyond the elastic layer but remains below the pleural surface) and PL2(tumor emerges on the pleural surface), is still not clear. <bold>Materials e methods:</bold> The aim of this retrospective, monocentric study, is to evaluate the relationship between PL1/PL2 and oncological outcomes(overall survival, cancer-specific survival and disease-free survival, DFS) of LUAD patients who underwent radical surgery in our Institution between 2014 and 2017. A multivariable analysis was conducted to assess the predictors of OS, CSS and DFS. The relationship between VPI grade and other well-known prognostic risk factors, as well as the site of the recurrence, was also evaluated. <bold>Results:</bold> Ninety-seven patients were included(PL1=55, PL2=42). The PL2 group presented worse survival outcomes(p≤0.001) than PL1 patients, independently from the pathologic stage(p<0.05). OS and CSS were significantly affected by PL2-VPI and by the prevalence of high-grade histological patterns(p<0.05). PL2-VPI, together with a low differentiation grade(G3), also significantly affected DFS(p<0.05). Moreover, PL2-VPI was strictly linked to the prevalence of a high-grade pattern(p=0.016), to a lower differentiation grade(p=0.005), to lymphovascular invasion(p<0.001) and to a greater incidence of distant recurrences(p=0.002) than PL1-VPI. <bold>Conclusions:</bold> Our findings, if supported by larger studies, may lead to considering patients-tailored adjuvant approaches for PL2-LUADs.