Cell cycle regulators show diagnostic and prognostic utility for differentiated thyroid cancer.

BACKGROUND: Differentiated thyroid cancer (DTC) generally has a favorable outcome, but some patients develop local recurrence and/or distant metastases and ultimately die of their disease. Molecular markers that accurately predict tumor behavior are lacking. This study's aim was to ascertain the role of cell cycle regulators in predicting malignant histology and tumor behavior in DTC. METHODS: Tissue microarrays consisting of 100 benign and 105 malignant thyroid lesions, plus 24 lymph node samples, were stained for p16, p21, p27, p53, p57, p63, cyclin D1, cyclin E, and mdm2. Statistical analysis was used to compare the expression of the markers in benign versus DTC lesions and correlate their expression with clinicopathologic characteristics. RESULTS: p16, p21, cyclin D1, and cyclin E showed significantly (P < .001) increased expression in DTCs compared with benign thyroid lesions (54.7% vs. 5%, 71.7% vs. 38%, 87.1% vs. 45.7%, and 72.3% vs. 37.4%, respectively). There was no significant difference in expression between benign lesions and DTC for the remaining markers. p16 expression correlated significantly with extrathyroidal tumor extension (P = .02) and the presence of cancer in lymph nodes (P = .03). A total of 73% vs. 45% of the cancers of patients with and without lymph node involvement, respectively, stained positive for p16 (P = .01). CONCLUSIONS: There is a statistically significant difference in the expression of p16, p21, cyclin D1, and cyclin E between DTCs and benign thyroid lesions, and p16 expression correlates with clinicopathologic variables predicting poor outcomes for DTC. These results suggest that evaluation of cell cycle derangement in thyroid tumors may serve as a useful tool for both DTC diagnosis and prognosis.

Hemithyroidectomy: the optimal initial surgical approach for individuals undergoing surgery for a cytological diagnosis of follicular neoplasm.

BACKGROUND: The primary objective of this study was to determine the true proportion and optimal surgical approach for individuals undergoing thyroid operation for a suspicion of cancer based on a fine-needle aspiration biopsy diagnosis of a follicular neoplasm (FN). A secondary objective of this study was to determine whether patient characteristics could assist the clinician in predicting malignancy in this FN patient cohort. METHODS: A retrospective chart, pathology, and cytology review of 370 consecutive primary thyroid operations was performed over a 4-year period at a tertiary care referral center. Clinical patient data were evaluated as an adjunct for predicting malignancy in the FN patient cohort. Univariate and multivariate analyses were used to investigate the association and the predictability. RESULTS: A total of 80 (22%) of the 370 patients underwent hemithyroidectomy to rule out cancer based on clinical presentation with a fine-needle aspiration biopsy diagnosis of FN. Fifteen (19%) of the FN cases were diagnosed as cancer by histological analysis (4 follicular carcinomas and 11 papillary carcinomas). Hemithyroidectomy was considered adequate treatment for 77 patients (96%). No patient characteristic significantly predicted the presence of cancer by either univariate or multivariate analysis. CONCLUSIONS: Overall, in the FN patient population, five hemithyroidectomies were performed to identify each cancer, and no further operation was required in 96% of patients. New diagnostic tools are needed to reduce the number of operations performed for benign pathology in patients with nodular thyroid disease and a needle biopsy diagnosis of FN.