Prognostic significance and grading of stromal invasion in pT1 adenocarcinoma of lung / 中华病理学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To study the prognostic significance of grading system for stromal invasion in pathologic tumor stage T1 (pT1) adenocarcinoma of lung.</p><p><b>METHODS</b>Eighty-five cases of surgically resected pT1 lung adenocarcinoma with clinicopathologic and follow-up data were retrospectively reviewed. The degree of invasive growth was classified into three grades according to its location in the tumor. The clinicopathologic characteristics and prognostic significance were analyzed.</p><p><b>RESULTS</b>Amongst the 85 cases studied, 17 cases (20%) were in grade 1, 12 (14%) in grade 2 and 56 (66%) in grade 3. The tumor size was smaller and lymphovascular permeation was less frequently encountered in cases with grade 1 stromal invasion than in those with grade 3 (P=0.005 for tumor size and P=0.018 for occurrence of lymphovascular permeation). The rate of lymph node metastasis and pathologic staging in cases with grade 1 and grade 2 were similar and were significantly lower than those with grade 3 (P=0.007 for rate of lymph node metastasis in grade 1 versus grade 3 tumors, P=0.002 for pathologic stage in grade 1 versus grade 3 tumors, P=0.027 for rate of lymph node metastasis in grade 2 versus grade 3 tumors and P=0.021 for pathologic stage in grade 2 versus grade 3 tumors). There was no statistically significant difference with respect to age, gender and smoking history of the patients, amongst cases in different grades. The overall five-year survival rate was 63%. The five-year survival rates for cases with grade 1, grade 2 and grade 3 were 100%, 83.3% and 46.6%, respectively. The difference between cases with grade 2 and grade 3 was statistically significant (P=0.027). The death rate during follow-up for cases with grade 1, grade 2 and grade 3 were 0, 16.7% and 42.9%, respectively. The difference between cases with grade 1 and grade 3 was statistically significant (P=0.001). Univariate analysis showed that grade of stromal invasion (P=0.001), pathologic stage (P<0.001), presence of lymphovascular permeation (P<0.001) and lymph node involvement (P<0.001) represented important prognostic factors. Multivariate analysis also showed that pathologic stage (P<0.001) was an independent prognostic factor.</p><p><b>CONCLUSIONS</b>The grading system of stromal invasion in pulmonary adenocarcinoma correlates with tumor prognosis and other prognostic factors. It represents a useful criterion in prognostic categorization of pT1 adenocarcinoma of lung.</p>