Within the last decade, the surgical management of thyroid nodules has undergone several key changes. In his talk on “Thyroid Cancer Surgery Updates,” Dr. Michael Yeh, Professor of Surgery at UCLA, discussed the evolution of his group’s practice since 2011. The introduction of molecular testing for indeterminate nodules, changes in the American Thyroid Association guidelines for the treatment of thyroid cancer, and refined use of surgeon-performed ultrasound have led to a new approach to thyroid surgery.
With the implementation of molecular genetic testing for indeterminate nodules in 2012, the endocrine surgery practice at UCLA saw a significant shift in the number of thyroid cancers found after surgery performed for diagnostic purposes. About 15% of nodules that undergo fine needle aspiration biopsy have “indeterminate” cytopathology. Of those indeterminate nodules that were surgically removed before the era of molecular testing, only 33% were proven malignant on final pathology. Once molecular testing was reflexively performed on all indeterminate nodules, two patterns emerged – the number of diagnostic surgeries being performed decreased, due to a number of “benign” molecular test results (Figure 1), and the percentage of cancers found with diagnostic lobectomies increased to 53-61% (Figure 2).
The rate of reoperation to remove the remainder of the thyroid gland after an initial “indeterminate nodule” resection has been in flux over this same time period. Initially, the percentage of diagnostic partial thyroidectomies that prompted completion thyroidectomies increased – this corresponded to a higher percentage of surgically removed indeterminate nodules actually being cancerous on final pathology. However, with the publication of the 2015 American Thyroid Association guidelines, thyroid lobectomy was increasingly accepted as adequate treatment for many differentiated thyroid cancers1. Thus, even when a diagnostic lobectomy yielded a cancerous nodule, no further treatment was necessary in many cases. The introduction of the diagnosis NIFTP (noninvasive follicular thyroid neoplasm with papillary-like nuclear features) served to downgrade a subset of thyroid disease from cancerous to non-cancerous, thereby allowing more surgical options (Figure 3). Perhaps in part due to the number of lobectomies performed for thyroid cancer and in part due to a more general philosophy of minimalism, the use of radioactive iodine ablation has decreased substantially in recent years as well.
While the general trend has been toward less extensive surgery for small tumors, total thyroidectomy remains recommended for certain patients, especially those with tumor extension beyond the thyroid capsule. At UCLA, surgeon-performed ultrasound has been instrumental in stratifying the risk of tumor extension and thus allowing for better operative planning. When ultrasound was negative for thyroid capsular distortion, a long interface between the tumor and the thyroid capsule, and tracheal indentation by the tumor margin, then thyroid lobectomy could be safely performed (Figure 4). In their experience, none of the patients who lacked those worrisome ultrasound features had tumor extension beyond the thyroid. They are also more likely to recommend total thyroidectomy for certain non-tumor factors, such as for patients who are already on thyroid hormone, have a high-normal preoperative TSH, have extensive family history of hypothyroidism, or prefer not to follow contralateral nodules post-operatively.
The institution of molecular testing and significant changes in national guidelines have opened the door for a much more individualized approach to the patient with a thyroid nodule in 2018. Overall, we have moved toward less surgery, both less frequent and less invasive. Dr. Yeh emphasized that with the increasing complexity of diagnostic and therapeutic tools, change needs to come from the entire patient team working as a unit.
1. Haugen BR1, Alexander EK2, Bible KC3 et al. 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer. Thyroid. 2016 Jan;26(1):1-133.
2. Kuo EJ, Thi WJ, Zheng F et al. Individualizing Surgery in Papillary Thyroid Carcinoma Based on a Detailed Sonographic Assessment of Extrathyroidal Extension. Thyroid. 2017 Dec;27(12):1544-1549.