Percentage of Newly Proposed High-Grade Patterns Is Associated with Prognosis of Pathological T1-2N0M0 Lung Adenocarcinoma

Objective To evaluate the prognostic value of the percentage of high-grade patterns (micropapillary, solid, and complex glands) in early-stage lung adenocarcinoma (LUAD). Methods A total of 1049 patients undergoing radical surgery with pathological T1-2N0M0 LUAD were screened retrospectively, and 191 patients were involved in the final analysis. Disease-free survival (DFS) was evaluated using the Kaplan–Meier curve and Cox regression analysis. The optimal cut-off value was determined using maximally selected rank statistics. Results The entire cohort was divided into quartile groups based on the percentage of high-grade patterns: Group 1 (≤ 30%), Group 2 (31–55%), Group 3 (56–85%), and Group 4 (≥ 86%). There were significant differences in smoking history ( P = 0.041), EGFR mutations ( P < 0.001), and ALK rearrangement ( P = 0.010) between the four groups, but no significant differences in other clinicopathological features. Kaplan-Meier analysis showed that a higher percentage of high-grade patterns predicted worse DFS ( P = 0.001), and multivariate analysis indicated that the percentage of high-grade patterns was an independent predictor (Group 2 vs. Group 1, HR = 2.136, P = 0.228; Group 3 vs. Group 1, HR = 3.355, P = 0.035; Group 4 vs. Group 1, HR = 5.147, P = 0.003, respectively). A cut-off value of 20% ( P = 0.048) and 50% ( P <0.001) for high-grade patterns were tested, and both revealed a significant difference in distinguishing DFS between subgroups. Conclusions The percentage of high-grade patterns is associated with the prognosis of early-stage invasive LUAD. A higher percentage indicates a worse prognosis.