Objective: To evaluate the relationship between visceral pleural invasion (VPI) and other clinicopathological features in lung adenocarcinoma with tumor size ≤3 cm, and to investigate the impact of VPI on the patients' prognosis. Methods: The clinical and pathological features were retrospectively reviewed in 231 cases of lung adenocarcinoma with the largest diameter of tumor ≤3 cm, following complete resection and systemic lymphadenectomy. VPI was divided into three grades, PL0, PL1 and PL2 according to modified Hammar classification for lung cancer upon elastic fiber staining. Survival analysis was performed by Kaplan-Meier method, and the risk factors for prognosis were explored by Cox proportional hazards model. Patient prognosis was evaluated by progression-free survival (PFS) and overall survival (OS). Results: In all 231 cases, the number of patients with VPI was 70 (30.3%), of which 61 cases were PL1 and 9 cases were PL2. The remaining 161 cases (69.7%) had no VPI (PL0). The tumor size (P=0.003), histological grade (P<0.01), the presence of solid component (P=0.001) and micropapillary component (P=0.009), N stage (P<0.01) and TNM stage (P<0.01) were significantly correlated with VPI. Patients with VPI had significantly shorter PFS and OS than those without VPI (P<0.01). There were significant differences in PFS and OS between patients with different VPI levels (P<0.01). Cox multivariate regression analysis showed that VPI was not an independent prognostic factor, whereas PL2 was an independent prognostic factor for PFS (P=0.007), but not an independent prognostic factor for OS (P=0.052). Conclusions: For patients with lung adenocarcinoma of tumor size ≤3 cm, VPI is related to poor prognosis; However, only PL2 is an independent prognostic factor for PFS. It may be not necessary to separate PL0 and PL1 status in smaller lung adenocarcinomas. Therefore, the definition of VPI may need further modification through large cohort studies.
目的： 评估肿瘤最大径≤3 cm的肺腺癌中脏层胸膜侵犯(VPI)与其他临床病理特征的关系，探讨VPI对肺腺癌患者预后的影响。 方法： 回顾性分析231例经手术完全切除及系统性淋巴结清扫且肿瘤最大径≤3 cm肺腺癌的临床病理资料，弹力纤维染色后按改良Hammar分级标准诊断VPI，并分为PL0、PL1、PL2三级。用Kaplan－Meier法进行生存分析，用Cox比例风险模型探寻预后的风险因素，以无进展生存期(PFS)和总生存期(OS)为主要研究终点。 结果： 在231例患者中，70例(30.3%)伴有VPI，其中61例为PL1、9例为PL2，其余161例(69.7%)未见VPI(PL0)。肿瘤大小(P＝0.003)、组织学分级(P<0.01)、实性成分(P＝0.001)、微乳头成分(P＝0.009)、N分期(P<0.01)及TNM分期(P<0.01)均与VPI分级显著相关。生存分析显示：有VPI患者的PFS和OS明显短于无VPI者(P<0.01)，不同VPI程度患者间PFS及OS差异有统计学意义(P<0.01)。Cox多因素回归分析表明：有无VPI不是影响患者预后的独立因子；而PL2是患者PFS的独立预测因素(P＝0.007)，但它不是OS的独立预测因素(P＝0.052)。 结论： 在肿瘤最大径≤3 cm的肺腺癌中，VPI与预后不良显著相关，但只有PL2是患者PFS的独立预测因素。因此，在肿瘤较小的肺腺癌中可能没有必要区分PL0和PL1，而VPI定义是否需要修改也有待进一步研究。.
Keywords: Adenocarcinoma; Lung neoplasms; Neoplasm invasiveness; Pleura; Prognosis.