[Validation of prognostic value of pathological staging in pathological stage Ⅰ lung adenocarcinoma]

Objectives: To examine the prognostic significance of WHO classification of lung adenocarcinoma in 2021 in patients with stage Ⅰ pulmonary adenocarcinoma. Methods: The clinical data of 829 patients who underwent surgery from January 2015 to September 2016 at Department of Thoracic Surgery, Zhongshan Hospital of Fudan University and had a postoperative pathologically confirmed diagnosis of stage Ⅰ lung adenocarcinoma were analyzed retrospectively. There were 389 males and 440 females, aged (60±11) years (range: 32 to 90 years), including 570 cases with solid nodules, 259 cases with ground-glass nodule. The survival curve was plotted using the Kaplan-Meier method and compared by the Log-rank test. The Cox proportional hazards regression model was used to identify prognosis factors on overall survival (OS), and recurrence-free survival (RFS). Results: Among the 829 patients, 470 cases were acinar predominant type, 165 cases were papillary predominant type, 90 cases were lepidic predominant type, 62 cases were solid predominant type, and 42 cases were micropapillary type. Compared with the solid nodule group, the proportion of patients with lepidic predominant type was higher in the ground glass nodule group (20.5%(53/259) vs. 6.5%(37/570), χ²=35.922, P<0.01), while the proportion of micropapillary (1.2%(3/259) vs. 6.8%(39/570), χ²=11.961, P<0.01) and solid predominant type (1.5%(4/259) vs. 10.2%(58/570), χ²=19.172, P<0.01) was lower. Survival analysis of 829 patients showed that patients with the lepidic predominant had the best prognosis, those with acinar and papillary predominant were worse, and patients with solid and micropapillary predominant had the worst prognosis (all P<0.01). The independent prognosis factors associated with postoperative recurrence were T2 stage (HR=1.631, 95%CI: 1.030 to 2.583, P=0.037), pathologic subtype (P=0.036), presence of a micropapillary component (HR=1.764, 95%CI: 1.143 to 2.722, P=0.010), and solid nodule in CT picture (HR=18.690, 95%CI: 7.587 to 46.043, P<0.01). Subgroup analysis showed that in both solid and ground-glass nodules, the presence of a solid-type component was a prognosis factor for overall survival, and the presence of a micropapillary component was a prognosis factor for recurrence-free survival. Conclusions: The presence of micropapillary and solid component, in addition to histological subtype, are prognosis factors for patients with stage Ⅰ lung adenocarcinoma. For patients with stage Ⅰ lung adenocarcinoma, the combination of pathological subtype and T-stage is more valuable and reliable for prognosis.