Rates of thyroid cancer in adults and children have seen a steep increase over the past decade, making it the fastest-rising cancer in the U.S. However, the reason behind that rise remains a subject of debate.
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“There has been a big push to minimize the number of scans done on kids because of radiation exposure, so it’s not like the adult population where we can confidently say, ‘yes, this is probably due to increased screening,’” says Rachel Georgopoulos, MD, pediatric otolaryngologist and Director of the Thyroid Head and Neck Oncology and Pediatric Endocrine Center (Thyroid HOPE).
Stefanie Thomas, MD, pediatric medical oncologist at Cleveland Clinic Children’s, concurs, adding, “I don’t think this is a case of overdiagnosis; it’s likely we’re picking up more patients with known genetic predispositions to cancer, screening those patients better, and possibly identifying them earlier in their course, rather than presenting to us as young adults.”
A demonstrated increase
A 2019 article in JAMA Otolaryngology-Head & Neck Surgery showed that after years of slow but steady increase (around 1% annually from 1973 to 2006), cases of pediatric thyroid cancer saw an annual increase of more than 9.5% between 2006 and 2013.
Cases in adults have also risen, but much of that increase is clearly attributable to increased screening and the detection of smaller and less dangerous tumors, asserts Dr. Georgopoulos.
Increased exposure to radiation may be one factor. Treatment regimens in childhood cancers, like Hodgkin’s lymphoma and leukemia, where patients received radiation treatment at a young age, and in some cardiac conditions requiring frequent imaging scans. Iodine deficiency, can also increase thyroid cancer risk, but that is not thought to be a problem in the United States, she adds
Notes Dr. Thomas, “We are seeing a genuine increase in a few different cancers in adolescents and young adults in the U.S, and these could be related to environmental exposures or diet, but there isn’t a clear answer on what is driving this trend.”
The standard of care
While cases may be increasing, the standard of care for pediatric thyroid cancer diagnosis and treatment remains the same.
The current method of diagnosis, including thyroid ultrasound and labs, utilizes a safe and effective approach that avoids additional radiation exposure. Biopsy of thyroid lesions is based not only on the size, but also the characteristics of a lesion, including genetic information.
“For example, we had a patient with p53 mutation and a thyroid lesion that was 0.8 cm, which we biopsied primarily because of this known genetic predisposition, as opposed to the size of the lesion.,” she says. “We have a much lower threshold to biopsy or repeat ultrasounds in children.”
In most cases, a thyroidectomy will be curative, although higher risk cases may go on to receive a full-body uptake scan to check for residual thyroid tissue and determine whether the patient will need additional treatment in the form of radioactive iodine.
“Pediatric thyroid cancer tends to have good outcomes and is managed mostly by our otolaryngology and endocrinology colleagues, but as medical oncologists, we partner to identify possible targeted therapies that may decrease morbidity associated with treatments, while also preserving good outcomes,” says Dr. Thomas.
A more recently published article in JAMA Otolaryngology-Head & Neck Surgery acknowledges this increasing incidence and shows additional data on risk for patients with multifocal disease. Findings suggest that patients age 10 or younger with T3 tumor stage and N1b nodal stage are at greater risk for multifocal disease.
Dr. Thomas is hopeful that this research may eventually lead to less invasive treatment for some patients. “We may get to a point where we’ve determined certain patients are better candidates for lobectomies, as opposed to total thyroidectomies, decreasing some of the intensity of the surgical resection in this patient population, and sparing those patients that morbidity.”
The Thyroid HOPE Center
One sign of this trend in cases is the appearance of thyroid clinics at medical centers across the country, including Cleveland Clinic’s. “We’re seeing a number of centers pop up, and they’re all brand new programs,” Dr. Georgopoulos says. “That speaks to a genuine need.”
These clinical collaborations are formalized in Cleveland Clinic’s Thyroid HOPE Center, which includes a team of pediatric otolaryngologists, endocrinologists and hematologist/oncologists, taking a multidisciplinary approach to pediatric thyroid cancer cases. The team also works with adult head and neck surgeons on some cases.
“There aren’t a lot of centers that have multidisciplinary clinics like the one we’ve established,” she notes.
Research is ongoing
Until more is known about the cause of the recent uptick in cases, there’s not much information physicians can share with their patients about how to minimize risks for pediatric thyroid cancer, Dr. Georgopoulos says. However, current research aims to better understand the causes and risk factors of the disease.
“That’s the million-dollar question,” Dr. Georgopoulos says. “While there are a host of known genetic factors that predispose patients to developing thyroid cancer, there is little we can do to prevent it.”