Marcia S. Brose, MD, PhD
After a decade of advances in the treatment of differentiated thyroid cancer, researchers are looking for ways to improve outcomes through a more personalized approach that includes risk-based strategies and appropriate use of molecular testing, according to experts who participated in an OncLive
Peer Exchange panel.
Many questions remain about which type of surgery patients need and how to optimally time and sequence therapies for advanced disease, the panel members said. They stressed the importance of multidisciplinary care, particularly through the relationship between endocrinologists and oncologists.
For cutting-edge care, patients should be treated at one of approximately 10 centers of excellence throughout the United States that are focusing on this malignancy, or community oncologists should explore partnering with specialists from such centers, said panelist Marcia S. Brose, MD, PhD.
“Although most patients with differentiated thyroid cancer have an excellent prognosis, a subset of these patients will develop a more aggressive, refractory phenotype,” said R. Michael Tuttle, MD, who served as moderator for the discussion. “Fortunately, recent understanding of the molecular pathogenesis of thyroid cancer has led to exciting novel therapies for advanced disease.”
Staging and Risk Assessment As recent guidelines recommend, biopsies should not be conducted uniformly on patients who are found to have thyroid nodules on an ultrasound, since up to 65% of the population may have such nodules, noted Naifa Busaidy, MD. She said a full evaluation of the entire neck should be conducted, which would include an ultrasound, a blood test for thyroid- stimulating hormone (TSH), and, depending on the TSH results, a radioactive iodine (RAI) uptake scan.
R. Michael Tuttle, MD
Busaidy said one of the most significant changes in thyroid guidelines is a greater emphasis on not conducting a biopsy on any nodule or even the dominant or large nodule, and focusing instead on nodules that look suspicious. This would include a nodule that has suspicious sonographic characteristics and is greater than 1.0 or 1.5 cm, she said. Suspicious lymph nodes should be biopsied as well.
Patients likely to do well with “simple therapy” tend to be females under 45 years of age with a nodule less than 4 cm and no lymph nodes on preoperative imaging, said Busaidy. These patients can be reassured that they likely will have a good outcome with standard therapy.
The prognosis is not as good for males, older patients, those with nodes greater than 4 cm, patients with extension of the tumor through the thyroid capsule, or for patients with bulky or large cervical or other neck lymph nodes, said Francis Paul Worden, MD. Highest risk is associated with metastatic disease.
Naifa Busaidy, MD
Most patients with extra thyroidal extension or extended lymph nodes should have not only an ultrasound but also a noncontrast CT scan of the chest because they will receive RAI, said Brose. Most of these patients will undergo surgery, and it is important not only to read the operative report but also to speak with the surgeon to learn what was found during the procedure, Busaidy pointed out.
Molecular biology is of growing importance in the management of differentiated thyroid cancer. Patients with RAS-like disease appear to respond better to RAI, while those with BRAF-like disease sometimes respond well to RAI therapy but are more likely to be refractory to it, said Eric J. Sherman, MD. Tumors with coexisting TERT and BRAF mutations “can be actually a lot more aggressive,” he said.
However, the value of early molecular testing has not yet been determined. Brose pointed out that since “90% to 95% of these patients will be cured with surgery and radioactive iodine alone, the testing won’t necessarily change your plan,” although “it might give you a clue” as to which patients are “more likely to be in that 5%.”