Micropapillary or solid pattern predicts recurrence free survival benefit from adjuvant chemotherapy in patients with stage IB lung adenocarcinoma.

BACKGROUND

Our study aimed to evaluate the prognostic significance and adjuvant chemotherapy (ACT) benefits of a micropapillary/solid (MS) pattern in patients with stage IB lung adenocarcinoma.

METHODS

Patients with pathologically-confirmed stage IB adenocarcinoma who underwent surgical resection between January 2009 and December 2011 were included. The tumors were reclassified into three categories: MS patterns absent (MS-); non-predominant MS patterns (MS+); predominant MS (MS++). The correlations of prognosis and ACT with recurrence-free survival (RFS) were evaluated.

RESULTS

Overall, 497 (MS-, n=269; MS+, n=177; MS++, n=51) patients were enrolled in the study. In univariate analysis, the MS+ [hazard ratio (HR), 1.437; 95% confidence interval (CI), 1.030-2.006; P=0.033] and MS++ (HR, 2.818; 95% CI, 1.792-4.432; P<0.001) groups had significantly poor prognosis compared with MS- group. Multivariate analysis revealed that age ≥65 (HR, 1.504; 95% CI, 1.077-2.099; P=0.017), serum level of carcinoembryonic antigen (CEA) ≥10 ng/mL (HR, 1.658; 95% CI, 1.048-2.623; P=0.031) and MS++ (HR, 2.529; 95% CI, 1.550-4.126; P<0.001) were significant prognostic factors. Furthermore, subgroup analysis showed that MS++ patients but not MS- and MS+ derived RFS (recurrence-free survival) benefit from ACT (HR, 0.357; 95% CI, 0.152-0.836; P=0.018).

CONCLUSIONS

MS pattern successfully differentiated the prognosis difference among stage IB lung adenocarcinomas and identified patients who benefitted from ACT.