Phytoestrogens and Thyroid Cancer Risk: A Population-Based Case-Control Study in Connecticut.

BACKGROUND: Very few previous studies have examined the relationship between thyroid cancer risk and intake of phytoestrogens (PE); furthermore, these studies have reached inconsistent results. METHODS: We analyzed data from a population-based case-control study in Connecticut from 2010 to 2011, including 387 histologically confirmed thyroid cancer cases and 433 population-based controls, with compound data available concerning specific PEs. Multivariate unconditional logistic regression models were used to estimate the associations between specific PEs and the risk of thyroid cancer, adjusting for potential confounders. RESULTS: An elevated risk of thyroid cancer was associated with moderate to high levels of coumestrol intake [OR = 2.48, 95% confidence interval (CI), 1.39-4.43 for 40-80 µg/day; OR = 2.41, 95% CI, 1.32-4.40 for 80-130 µg/day; and OR = 2.38, 95% CI, 1.26-4.50 for >200 µg/day compared with <40 µg/day], and the main elevation in risk appeared among microcarcinomas (≤1 cm). A decreased risk of papillary macrocarcinomas (>1 cm; OR = 0.26, 95% CI, 0.08-0.85 for 1,860-3,110 µg/day compared with <760 µg/day) was associated with moderate genistein intake among women. CONCLUSIONS: Our study suggests that high coumestrol intake increases the risk of thyroid cancer, especially microcarcinomas, whereas moderate amounts of genistein intake appear to be protective for females with thyroid macrocarcinomas. IMPACT: The study highlights the importance of distinguishing between microcarcinomas and macrocarcinomas in future research on the etiology of thyroid cancer.

The American Association of Endocrine Surgeons Guidelines for Definitive Management of Primary Hyperparathyroidism.

Importance: Primary hyperparathyroidism (pHPT) is a common clinical problem for which the only definitive management is surgery. Surgical management has evolved considerably during the last several decades. Objective: To develop evidence-based guidelines to enhance the appropriate, safe, and effective practice of parathyroidectomy. Evidence Review: A multidisciplinary panel used PubMed to review the medical literature from January 1, 1985, to July 1, 2015. Levels of evidence were determined using the American College of Physicians grading system, and recommendations were discussed until consensus. Findings: Initial evaluation should include 25-hydroxyvitamin D measurement, 24-hour urine calcium measurement, dual-energy x-ray absorptiometry, and supplementation for vitamin D deficiency. Parathyroidectomy is indicated for all symptomatic patients, should be considered for most asymptomatic patients, and is more cost-effective than observation or pharmacologic therapy. Cervical ultrasonography or other high-resolution imaging is recommended for operative planning. Patients with nonlocalizing imaging remain surgical candidates. Preoperative parathyroid biopsy should be avoided. Surgeons who perform a high volume of operations have better outcomes. The possibility of multigland disease should be routinely considered. Both focused, image-guided surgery (minimally invasive parathyroidectomy) and bilateral exploration are appropriate operations that achieve high cure rates. For minimally invasive parathyroidectomy, intraoperative parathyroid hormone monitoring via a reliable protocol is recommended. Minimally invasive parathyroidectomy is not routinely recommended for known or suspected multigland disease. Ex vivo aspiration of resected parathyroid tissue may be used to confirm parathyroid tissue intraoperatively. Clinically relevant thyroid disease should be assessed preoperatively and managed during parathyroidectomy. Devascularized normal parathyroid tissue should be autotransplanted. Patients should be observed postoperatively for hematoma, evaluated for hypocalcemia and symptoms of hypocalcemia, and followed up to assess for cure defined as eucalcemia at more than 6 months. Calcium supplementation may be indicated postoperatively. Familial pHPT, reoperative parathyroidectomy, and parathyroid carcinoma are challenging entities that require special consideration and expertise. Conclusions and Relevance: Evidence-based recommendations were created to assist clinicians in the optimal treatment of patients with pHPT.

Use of Dietary Vitamin Supplements and Risk of Thyroid Cancer: A Population-Based Case-Control Study in Connecticut.

Certain dietary supplements have been reported to increase the risk of some cancers. Over half of the US population regularly uses dietary supplements. Thyroid cancer incidence has increased over the past several decades. However, few studies have investigated the association between dietary supplements and thyroid cancer. Thus, it is essential to clarify any association between dietary supplements and risk of thyroid cancer. MATERIALS AND METHODS: A population-based case-control study in Connecticut was conducted during 2010-2011 among 462 histologically confi rmed incident thyroid cancer cases and 498 population-based controls. Dietary supplement intake was ascertained through in-person interviews and a food frequency questionnaire. Multivariate unconditional logistic regression models were used to estimate the risk of thyroid cancer and dietary supplement use. RESULTS: Overall, no statistically signifi cant associations were observed between dietary supplementation and thyroid cancer risk. Stratifi ed analyses revealed a suggestive protective effect on risk of papillary microcarcinoma among longterm (> 10 years) use of multivitamins (OR = 0.59, 95 % CI: 0.33, 1.04) and calcium supplementation (OR = 0.45, 95 % CI: 0.22, 0.93). An increased risk of large papillary thyroid cancers (tumor size > 1 cm) was observed among short-term (< 5 years) users of calcium supplements (OR = 2.24, 95 % CI: 1.30, 3.88). DISCUSSION: No signifi cant associations were observed between supplementation and overall thyroid cancer risk. The different associations between calcium supplements and risk of papillary thyroid cancer by tumor size warrant further investigation.

Papillary thyroid cancer.

In summary, PTC is common, although it rarely results in disease-specific mortality. It is being diagnosed increasingly in the subclinical phase as a result of enhanced ultrasound imaging and more aggressive surveillance of smaller thyroid nodules. US-guided FNA is the "gold-standard" for diagnosis. Although controversy continues about the appropriate surgical management of PTC, total thyroidectomy is usually indicated given the frequent multicentricity and metastases of the disease, which in turn, necessitates adjuvant RAI and careful surveillance. An enhanced prognostic classification could better guide initial surgical therapy, standardize surveillance, and reduce the risk of recurrent and persistent disease. Research efforts should focus on the genetic and molecular underpinnings of PTC, as these would facilitate the identification of additional prognostic factors and potential targets for novel therapies.

Open minimally invasive parathyroid surgery.

Outpatient minimally invasive parathyroidectomy (MIP) employs (1) preoperative parathyroid localization with high quality sestamibi scans, (2) cervical block anesthesia, (3) limited exploration, and (4) the rapid intraoperative parathyroid hormone assay to confirm an adequate resection. The technical aspects of this procedure are described, and the results obtained in 255 patients who underwent MIP are compared with those of 401 patients who underwent conventional bilateral cervical exploration under general anesthesia. MIP and standard exploration were indistinguishable with regard to high cure and low complication rates. MIP, however, was superior with regard to operating time, length of hospital stay, patient comfort, and costs.