Significant racial differences in the incidence and behavior of the follicular variant of papillary thyroid carcinoma.

BACKGROUND: Increased detection of papillary thyroid cancer (PTC) has led to overtreatment of the largely indolent follicular variant (fvPTC). To guide management of non-aggressive lesions, we investigated whether race predicts PTC variant and tumor behavior. METHODS: Analysis of 258 973 patients from the National Cancer Database diagnosed with PTC in 2004-2014. Clinical and tumor information was compared by race. Multivariate logistic regression was used to predict fvPTC, extrathyroidal extension (ETE), and lymph node metastasis (LNM) of fvPTC. RESULTS: Blacks had the highest fvPTC rate (40% vs white 30%, Hispanic 26%, Asian 25%, P < .001). Blacks had higher odds of fvPTC (aOR = 1.33, 95% CI: 1.28-1.37) and lower odds of ETE than whites (aOR = 0.90, 95% CI: 0.82-0.99) (P < .001). Hispanics and Asians had lower odds of fvPTC (aOR = 0.89, 95% CI: 0.86-0.92 and aOR = 0.81, 95% CI: 0.79-0.84) and higher odds of LNM and ETE than whites (P < .001). CONCLUSIONS: Racial disparities in fvPTC incidence and behavior should be considered to optimize diagnosis and treatment planning.

Mutational Analysis in Pediatric Thyroid Cancer and Correlations with Age, Ethnicity, and Clinical Presentation.

BACKGROUND: Well-differentiated thyroid cancer (WDTC) incidence in pediatrics is rising, most being papillary thyroid carcinoma (PTC). The objective of the study was to assess the prevalence of different mutations in pediatric WDTC and correlate the genotype with the clinical phenotype. METHODS: This is a single-center retrospective study. Thyroid tissue blocks from 42 consecutive pediatric WDTC patients who underwent thyroidectomy between 2001 and 2013 were analyzed at Quest Diagnostics for BRAF(V600E), RAS mutations (N,K,H), and RET/PTC and PAX8/PPARγ rearrangements, using validated molecular methods. Thyroid carcinomas included PTC, follicular thyroid carcinoma (FTC), and follicular variant of PTC (FVPTC). RESULTS: Thirty-nine samples (29 females) were genotyped. The mean age at diagnosis was 14.7 years (range 7.9-18.4 years), and most were Hispanic (56.4%) or Caucasian (35.9%). The mean follow-up period was 2.9 years. Mutations were noted in 21/39 (53.8%), with both BRAF(V600E) (n = 9), and RET/PTC (n = 6) detected only in PTC. Mutations were detected in 2/5 FTC (PAX8/PPARγ and NRAS) and 3/6 FVPTC cases (PAX8/PPARγ). Of 28 PTC patients, 57.1% had mutations: 32.1% with BRAF(V600E), 21.4% with RET/PTC, and 3.6% with NRAS. Of patients with BRAF(V600E), 77.8% were Hispanic and 88.9% were >15 years, while all RET/PTC-positive patients were ≤15 years (p = 0.003). Tumor size, lymph node involvement, and distant metastasis at diagnosis (or soon after (131)I ablation) did not vary significantly based on the mutation. CONCLUSIONS: BRAF(V600E) was the most common mutation, especially in older and Hispanic adolescents. A larger, ethnically diverse pediatric cohort followed long term will enable the genotypic variability, clinical presentation, and response to therapy to be better assessed.

Thyroid cancer in Pacific women in New Zealand.

AIM: To describe trends in incidence rates of thyroid cancer in New Zealand between 1981-2004 with a particular focus on Pacific women. METHOD: Linked census-cancer registration data was used to calculate age standardised cancer incidence rates for thyroid cancer. Both trends over time amongst Pacific women, and differences in rates between Pacific and European/Other women in New Zealand, were assessed. RESULTS: Rates of thyroid cancer in New Zealand were higher for women than men. The highest rates of thyroid cancer in were observed amongst Pacific women with a pooled age-standardised incidence rate of 18.5/100,000 (95%CI 14.6-22.4/100,000) compared to 5.2/100,000 (95% 4.8-5.5/100,000) for European/Other; SRR 3.58 (95%CI 2.87-4.47). Sparse data mean it is difficult to clearly identify a trend over time for Pacific women but European women experienced a 73% increase from 4.0/100,000 (95%CI 3.3-4.6/100,000) in 1981=1986 to 6.9/100,000 (95%CI 5.9-7.8/100,000) in 2001-2004 (Ptrend=0.05). CONCLUSIONS: Pacific women in New Zealand have the highest rates of thyroid cancer among resident ethnic groups. Risk was highest for Pacific women over 45 years of age. More research needs to be done looking at which specific ethnicities are driving rates of thyroid cancer in New Zealand and whether the risk is influenced by birthplace and age at migration to New Zealand.

Incidence of thyroid malignancy among goitrous thyroid lesions from the Sarawak General Hospital 2000-2004.

INTRODUCTION: Thyroid cancer is the most common among all endocrine malignancies. The worldwide prevalence of goitre in the general population is estimated at 4-7 percent and the incidence of malignancy in goitrous thyroid is about ten percent. It is postulated that goitrous thyroid is a precursor lesion to the development of malignant thyroid diseases. As Sarawak is a state well known for endemic goitre, this study focused on establishing the incidence of thyroid malignancy among goitrous thyroid swellings. METHODS: This study was a hospital-based retrospective study on the archived collection of the surgically-removed thyroid specimens from the Sarawak General Hospital, Malaysia. Cases were grouped into cancer and non-cancer groups. The cancer group included papillary thyroid carcinoma (PTC), PTC follicular variant, follicular carcinoma and anaplastic carcinoma (ANA). RESULTS: A total of 820 thyroid cases which underwent surgical removal in years 2000 to 2004 were collected. Of these, 143 (17.4 percent) were male and 677 (82.6 percent) female. It was observed that the highest prevalence of thyroid swelling cases occurred in the age group 41-60 years while the lowest prevalence occurred in the age group under 21 years, 371 (45.2 percent) vs. 31 (3.8 percent). By ethnicity, the Ibans and Malays were found to have a higher prevalence at 275 (33.5 percent) and 196 (23.9 percent), respectively, while the lowest prevalence was observed in Indians, 11 (1.3 percent). 55 cases (6.7 percent) were found to be cancerous and the rest (93.3 percent) were non-cancerous thyroid swellings. Histologically, the highest incidence of carcinoma was PTC (4.0 percent) and the lowest was ANA (0.2 percent). CONCLUSION: Based on our observations, although goitrous thyroid swelling is quite a common problem in Sarawak, thyroid malignancy is not a major issue. Among thyroid malignancies, PTC is the most common histological type of malignancy.