Postinduction positron emission tomography assessment of N2 nodes is not associated with ypN2 disease or overall survival in stage IIIA non–small cell lung cancer

Abstract

ObjectiveInduction therapy is often recommended for patients with clinical stage IIIA-N2 (cIIIA/pN2) lung cancer. We examined whether postinduction positron emission tomography (PET) scans were associated with ypN2 disease and survival of patients with cIIIA/pN2 disease. MethodsWe performed a retrospective review of a prospectively maintained database to identify patients with cIIIA/pN2 non–small cell lung cancer treated with induction chemotherapy followed by surgery between January 2007 and December 2012. The primary aim was the association between postinduction PET avidity and ypN2 status; the secondary aims were overall survival, disease-free survival, and recurrence. ResultsPersistent pathologic N2 disease was present in 61% of patients (61 out of 100). PET N2-negative disease increased from 7% (6 out of 92) before induction therapy to 47% (36 out of 77) afterward. The sensitivity, specificity, and accuracy of postinduction PET for identification of ypN2 disease were 59%, 55%, and 57%, respectively. Logistic regression analysis indicated that postinduction PET N2 status was not associated with ypN2 disease. Of the 39 patients with both pre- and postinduction PET N2-avidity, 25 (64%) had ypN2 disease. The 5-year overall survival was 40% for ypN2 disease versus 38% for N2-persistent disease (P = .936); the 5-year overall survival was 43% for postinduction PET N2-negative disease versus 39% for N2-avid disease (P = .251). The 5-year disease-free survival was 34% for ypN2-negative disease versus 9% for N2-persistent disease (P = .079). ConclusionsPostinduction PET avidity for N2 nodes is not associated with ypN2 disease, overall survival, or disease-free survival in patients undergoing induction chemotherapy for stage IIIA/pN2 disease.