Thyroid nodules are very common, with over 60% of people having one or more nodule by around age 70, according to the American Thyroid Association. While most nodules form in the lobes of the thyroid, a small percentage of nodules originate from the isthmus—a bridge of tissue connecting the right and left lobes of the thyroid. These isthmic thyroid nodules have been associated with a higher risk of cancer. Other than their point of origin, not much is known about the difference between isthmic and lobar thyroid nodules.
A new study from a multidisciplinary team at Washington University School of Medicine in St. Louis examined the molecular differences between isthmic and lobar thyroid nodules and thyroid cancer to understand why nodules originating in the isthmus are more likely to become cancerous, and why isthmic thyroid cancers tend to be more aggressive.
The study was published Nov. 11 in Thyroid.
“Our studies suggest isthmic nodules are more likely to have malignant cytology and increased rates of higher risk molecular alterations compared with lobar nodules,” says lead author Sina Jasim, MD, MPH, an associate professor of medicine in the Division of Endocrinology, Metabolism & Lipid Research at WashU Medicine.
This study builds on a pilot study by Jasim and Taylor Brown, MD, MHS, an assistant professor of surgery in the Section of Surgical Oncology, published in the American Journal of Surgery. The previous study showed that thyroid cancers originating in the isthmus have a different molecular profile than lobular thyroid cancers.
The recently published study, the team analyzed more than 170,000 thyroid nodules utilizing Afirma thyroid nodule database, to further analyze and validate the above findings
“This study represents the critical importance of collaboration between endocrinology and endocrine surgery,” says Brown. “The environment at WashU Medicine allows us to combine our expertise to see the bigger picture, which in turn leads to advances in how we care for our patients.”
The researchers believe these findings, along with other clinical and pathological factors, may ultimately lead to a change in the management approach to thyroid nodules and thyroid cancer based on their origin and location along with their molecular analysis leading to more personalized management plan to patient with thyroid tumors.
“Our data may influence treatment decisions and monitoring for those patients and should be considered when planning surgical approach in isthmic relative to lobar differentiated thyroid cancers,” says Jasim.