Primary Care Otolaryngology

Chapter 15

Treatment of papillary carcinoma is somewhat controversial. Historically, a total thyroid lobectomy and isthmectomy have been used to treat smaller papillary thyroid cancers (<1 cm). More recently, the trend has been toward total thyroidectomy in patients with nodules containing pap- illary thyroid cancers. Newer evidence from a study by Mazzaferri and colleagues suggests that total thyroidectomy, when compared to subtotal, may significantly decrease the local recurrence rate (18% versus 7%), and ultimately the number of deaths (from 1.5% to 0.03%). 1 This study also points out that patients treated with radioactive iodine and thyroid hor- mone suppression have a decreased incidence of recurrence (3%), com- pared to those treated with thyroid suppression alone (11%). However, there was no difference in the number of deaths between these two groups. As mentioned earlier, if cervical metastatic thyroid cancer is present, a modified or selective neck dissection is indicated, depending on the location of the disease. The greatest risks of thyroid surgery are hypopara- thyroidism secondary to injury or removal of the parathyroid glands, and recurrent laryngeal nerve injury, which may result in hoarseness, short- ness of breath, and reduced exercise tolerance. Follicular Carcinoma Approximately 15 percent of thyroid cancers is the follicular cell type. The surgical specimen of all thyroid cancers must be sectioned completely to determine if the tumor capsule and/or lymphatic and blood vessels are invaded. The findings of capsular and/or lymphovascular invasion are essential for diagnosis and cannot be determined by a fine-needle aspi- rate. Cytopathologically, the cells may also look fairly benign on fine-nee- dle aspirate, so many specimens are interpreted as “consistent with adeno- ma, cannot rule out follicular carcinoma.” This tumor metastasizes via the blood. Two major types of follicular carcinoma are microinvasive and macroinvasive. A variant is Hürthle cell carcinoma, which is a more aggressive form of follicular thyroid cancer and is marked by a high fre- quency (75% or more) of Hürthle cells. Like papillary carcinoma, follicular carcinoma has an affinity for radioac- tive iodine. Since iodine is concentrated in normal thyroid tissue, an attempt to remove all thyroid tissue allows a higher dose to be delivered to

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1 Mazzaferri, E.T., et al. A vision for the surgical management of papillary thyroid carcinoma: extensive lymph node compartmental dissections and selective use of radioiodine. Journal of Clinical Endocrinology & Metabolism 2009 Apr; 94(4):1086-1088.

Primary Care Otolaryngology