CONCORDANCE OF PRE-OPERATIVE CLINICAL STAGE WITH PATHOLOGIC STAGE IN PATIENTS ≥45 YEARS OLD WITH WELL-DIFFERENTIATED THYROID CANCER

Clinical stage (cStage) in thyroid cancer determines extent of surgical therapy and completeness of resection. Pathologic stage (pStage) is an important determinant of outcome. The rate of discordance between clinical and pathologic stage in thyroid cancer is unknown. The National Cancer Data Base was queried to identify 27,473 patients ≥45 years old with cStage I through IV differentiated thyroid cancer undergoing surgery from 2008-2012. There were 16,286 (59.3%) cStage I patients; 4,825 (17.6%) cStage II; 4,329 (15.8%) cStage III; and 2,013 (7.3%) cStage IV patients. The upstage rate was 15.1%, and the downstage rate was 4.6%. For cStage II, there was a 25.5% upstage rate. The change in cStage was a result of inaccurate T-category in 40.8%, N-category in 36.3%, and both in 22.9%. On multivariate analysis, the patients more likely to be upstaged had papillary histology, tumors 2.1 to 4 cm, total thyroidectomy, nodal surgery, positive margins, or multifocal disease. Upstaged patients received radioiodine more frequently (75.3% vs. 48.1%; P