Jacques How

Explaining the increasing incidence of differentiated thyroid cancer

The thyroid is the largest of the endocrine glands and by far the most common site of all primary endocrine cancers. However, thyroid cancer is relatively rare, accounting for only 1% of all cancers. The number of new cases diagnosed each year is comparable to that of leukemia, pancreatic cancer and

Body Mass Index in the Evaluation of Thyroid Cancer Risk

BACKGROUND Obesity has been linked to numerous diseases including thyroid cancer, but the exact nature of the relationship, especially with respect to patients with thyroid nodules, remains unclear. The objective of this study was to evaluate the impact of body mass index (BMI) on thyroid cancer risk in a population of patients with indeterminate cytology on fine-needle aspiration biopsy (FNAB). METHODS A total of 253 consecutive patients with indeterminate thyroid nodule FNABs who underwent total thyroidectomy in a tertiary care teaching hospital between 2002 and 2007 were reviewed. Height and weight reported on the anesthesia summary were recorded for each patient. Malignancy rates were calculated for the underweight, normal, overweight, and obese groups stratified according to their BMI. Subanalyses according to age and sex were also performed. RESULTS The risk of malignancy tended to be lower in obese patients compared to patients with BMIs in the underweight, normal, and overweight ranges (52% vs. 61%, p = 0.195). In men, a BMI classified as obese was associated with a significantly lower rate of malignancy (36% vs. 72%, p = 0.003). Women older than 45 years were a subgroup in which higher malignancy rates were associated with obesity (65% vs. 54%, p = 0.293). Conversely, in men over the age of 45 years and women under 45 years, a BMI in the obesity range was linked to a lower incidence of malignancy (20% vs. 68% p = 0.009 and 36% vs. 68% p = 0.043, respectively). When older women were excluded from the population studied, the rate of malignancy in obese patients was 36% versus 70% in nonobese patients (p = 0.002) with an associated reduction of 5% in the risk of malignancy per increased unit of BMI. CONCLUSIONS For patients with FNAB results of indeterminate significance, a higher BMI correlates with lower rates of thyroid malignancy for all patients except women over the age of 45 years.

The role of sentinel lymph node biopsy in differentiated thyroid carcinoma.

OBJECTIVE To determine whether sentinel lymph node (SLN) biopsy can accurately predict central compartment metastasis in patients with differentiated thyroid carcinoma. DESIGN Prospective clinical study. SETTING Academic tertiary care center. PATIENTS Ninety-eight patients (82 women and 16 men; mean age, 48.3 years) underwent a total thyroidectomy and central compartment dissection. INTERVENTION Peritumoral injection of methylene blue dye, 1%, followed by SLN biopsy. MAIN OUTCOME MEASURES The final pathology report established the presence of metastasis among SLNs and lymph nodes that did not stain blue (non-SLNs [NSLNs]). RESULTS Differentiated thyroid carcinoma was found in 75 of 98 patients (77%). Seventy of 75 patients with differentiated thyroid carcinoma presented with SLNs and/or NSLNs within the central compartment. Fifteen of 70 patients had metastasis-positive SLNs, while 55 had metastasis-negative SLNs. Six of 15 patients with positive SLNs also had positive NSLNs. No patients with negative SLNs were found to have positive NSLNs. Sentinal lymph node status was a highly significant predictor of NSLN result (Fisher exact test, P < .001). The accuracy, sensitivity, specificity, and positive and negative predictive values of SLN biopsy were 87%, 100%, 86%, 40%, and 100%, respectively. CONCLUSIONS To our knowledge, this is the largest series of SLN biopsy in patients with differentiated thyroid carcinoma. Our experience suggests that this is an accurate and noninvasive means to identify subclinical lymph node metastasis. Because negative SLNs correlate strongly with a negative central compartment (100% in this study, P < .001), this technique can be used as an intraoperative guide when determining the extent of surgery necessary in cervical level VI.

Sentinel Lymph Node Biopsy in Well Differentiated Thyroid Cancer

The management of occult cervical lymph node metastasis in well-differentiated thyroid cancer (WDTC) is controversial. Given the risks of hypocalcemia, recurrent laryngeal nerve injury, and increased operative time with a central compartment neck dissection (CCND), a routine adoption of prophylactic lymph node dissection has not been accepted by many as a standard management for occult metastasis (Henry et al., 1998; Pereira et al., 2005; Shen et al., 2010). Conversely, other thyroid surgeons feel that the complication rate is low and that the benefits of CCND outweigh the risks (Anand et al., 2009; Haigh et al., 2000; Keleman et al., 1998; Pelizzo et al., 2001; Pitman et al., 2003; Rettenbacher et al., 2000). As a result, sentinel lymph node biopsy (SLNB) has gained an increase in popularity in recent years.

Sequential Thyroid Storm and Myxedema Coma: A Unique Case Report

Background and objective: Both thyroid storm and myxedema coma are rare life-threatening events and carry a high mortality rate. Our objective is to document a unique case of sequential thyroid storm and myxedema coma. Results: We report a very unusual case of a 46-year-old female patient who presented initially in 2002 with thyroid storm caused by a previously undiagnosed Graves’ disease. After two doses of radioactive iodine treatment, she developed hypothyroidism for which she was placed on l-thyroxine replacement therapy. She was lost to followup and, indeed, she failed to take her l-thyroxine medication and in the fall of 2010, she presented to our Emergency Department with myxedema coma, which was treated successfully. Conclusion: A careful and life-long follow-up is essential in patients who have received thyroid radioactive iodine ablation or total thyroidectomy to ensure that their thyroidal status remains stable. This constitutes the first step in the prevention of myxedema coma, a diagnosis which still carries an appreciable mortality rate.