Updated Thyroid Cancer Treatment Guidelines Reflect Advances In Care

By Bryan R. Haugen, MD

Thyroid nodules (lumps) and differentiated thyroid cancer (DTC, a non-aggressive form of thyroid cancer which usually grows slowly and can be cured) are quite common. The number of cases diagnosed in the last few decades has increased a great deal. This is largely due to their discovery by CT scans, MRIs and ultrasounds performed for non-thyroid conditions.

As most of these nodules do not have any symptoms due to thyroid enlargement or malfunction, a framework for how best to approach the clinical care and treatment of these nodules is crucial. The American Thyroid Association (ATA) released thyroid nodule clinical guidelines in 2009, but significant advances in the field since that time have led to evidence-based revisions and new, more individualized recommendations.

Released in October 2015 by an ATA task force composed of experts in the field, the new guidelines for thyroid nodules and DTC provide valuable, updated information to help physicians and patients determine when intervention is necessary and when to take a more conservative approach to evaluation, surveillance, disease management and surgical approaches to thyroid nodules.

So what are the important points made in this comprehensive document that you should be aware of when you are told you have a thyroid nodule? Let’s focus on five areas that show significant advancements that I believe will, or should, change the way we think about thyroid nodules and DTC, and thus impact the care and management of thyroid nodules.

Ultrasound of the thyroid: what the nodule appearance says about whether there should be concern

Many specialists use specific ultrasound features, as well as different combinations of ultrasound features, to assess the risk of malignancy in those with thyroid nodules in order to guide which thyroid nodules should undergo fine-needle aspiration (FNA) biopsy. An FNA is a procedure in which the physician uses a fine gauge needle to collect a small sample of thyroid tissue for a biopsy. Not all nodules require biopsy. Nodule features that help determine the need for an FNA include hypoechogenicity (darker than normal tissue); whether a nodule is more solid or more liquid; irregular nodule borders; bright, internal-appearing spots suggestive of microcalcifications (small specks of calcium), which are the formation of a solid or semi-solid lumps within the thyroid gland; blood flow pattern; and a shape that is taller than it is wide.

Other investigators have attempted to develop scoring systems for risk of malignancy. The new guidelines use a scoring system to develop a risk pattern (high, intermediate, low and very low risk, as well as a benign pattern). The guidelines include a number of examples of thyroid nodule appearance to show each risk pattern, which will be useful immediately as a comparison for those who perform ultrasound and review ultrasound images.

Not all thyroid nodules need biopsy

Based on the ultrasound risk pattern discussed above, the task force guidelines provide a detailed approach to biopsy of thyroid nodules. If your physician believes your risk pattern suggests a “high” or “intermediate risk” nodule, a biopsy should be performed for nodules in this category which are one centimeter (just under ½”) or larger in size. For those nodules with “low” risk for malignancy, it is reasonable to biopsy slightly larger nodules, those over 1.5 centimeters. And for “very low” risk pattern nodules, biopsy is not recommended, if at all, until the nodule is over two centimeters in size. So size matters as well as risk pattern. And if the appearance of the nodule suggests a purely cystic (fluid-filled) nodule, you do not need a biopsy.

Overall, the feeling among experts is that very small nodules, even if they look a bit suspicious for cancer, do not automatically require biopsy. The risk of identifying cancer in these nodules is admittedly high, but emerging evidence shows that patients tend to do very well with only ongoing observation and careful follow-up. However, if these nodules grow, or if new, abnormal-looking lymph nodes appear on subsequent ultrasounds, the patient’s ongoing evaluation and treatment plan will change. (Editor’s note: Lymph glands are any of numerous bean-shaped masses in the neck that are part of our immune system. They are made up of white blood cells called lymphocytes that help fight infection).

Using biopsy and/or surgical tissue appearance helps guide treatment

The key to any appropriate disease management is good and complete data. The task force feels that a careful and comprehensive review of biopsied tissue features that help predict recurrence rates is needed. A prime example is the reporting of lymph node involvement. Evidence shows that the rate of recurrent or persistent disease is higher if you have more than five involved lymph nodes, nodes that contain tumors more than three centimeters in size and nodes that show that the cancer has spread outside the node margins (the margin is the area where the nodule is in contact with normal tissue). This approach will need continued review and perhaps even further clarification as time goes on and more data is collected on how many traits are needed for optimal decision-making.

Response to therapy

Physicians need to assess the risk of persistent and recurrent disease over time. Thyroid cancer is typically very slow growing and we know that, once treated, it can recur even years later. The 2015 guidelines have attempted to categorize patient groups to include “excellent,” “indeterminate,” “biochemical incomplete” and “structural incomplete” responses to therapy. Being in one defined group, however, can change over time to being in another, so it is very important for patients to schedule ongoing follow-up and reassessment clinic visits. But these categories are supported by emerging evidence that hopefully will provide physicians with a uniform way to communicate to you and other medical providers your ongoing risk of recurrent/persistent disease.

Managing thyroid cancer when radioactive iodine treatment does not work

The guidelines include 11 recommendations to help guide treatment for individuals with thyroid cancer in the relatively uncommon event that surgery and radioactive iodine therapy are not effective, including when other therapies could be considered. These include surgery; thermal ablation, a clinically advanced technique in which focused ultrasound produces cell death in a targeted area with minimal damage to the surrounding tissue; radiotherapy; or alcohol ablation. This involves injecting small thyroid cancers with alcohol using imaging such as ultrasound to ensure precise placement of the injection.

Also included are recommendations regarding when individuals should be considered for clinical trials and who to consider for chemo-like therapy. A detailed discussion of these approaches is beyond the scope of this article, but knowledge about who these treatments might be beneficial for is increasing.

While there are many areas of treatment for thyroid nodules and thyroid cancer that still require more study data to fully understand their potential role in optimal treatment and management, these newly published guidelines are a significant step forward and will help physicians determine when to intervene and when its best to take a more conservative approach.

For more information on thyroid cancer, visit http://thyroidawareness.com/thyroid-cancer.

Dr. Bryan R. Haugen is Professor of Medicine and Pathology at the University of Colorado Denver. He is also Chief of the Division of Endocrinology, Metabolism & Diabetes and Director of the Thyroid Tumor Program, which monitors and manages more than 2,500 patients with thyroid cancer. His current clinical interests include thyroid neoplasms, advanced thyroid cancer, thyroid dysfunction and other endocrine tumors (parathyroid, adrenal, carcinoid). Dr Haugen is a member of the American Association of Clinical Endocrinologists (AACE).