Rebecca S. Sippel, MD
The initial surgical procedure performed for the management of medullary thyroid cancer (MTC) is the best chance surgeons have for a cure; the wrong or inadequate operation is not only dangerous but could potentially prevent patients from ever being effectively cured of their disease, experts here suggested.
“One of the challenges in MTC is making the diagnosis preoperatively,” Rebecca S. Sippel, MD, associate professor of surgery, University of Wisconsin, Madison, Wisconsin, told delegates here on September 20. Sippel was speaking at the annual meeting of the American Thyroid Association.
Up to 30% to 40% of MTC diagnoses are not made preoperatively, she added, in part because surgeons think they are going to remove the nodule anyway.
However, as Sippel emphasized, if the diagnosis is not made before surgery, surgeons cannot adequately plan their operative strategy or make arrangements for any pre-operative interventions that must be taken prior to initiating surgical treatment for the cancer itself. Thus, when a patient presents with a clinically apparent MTC, “the first thing you need to do is confirm the diagnosis,” Sippel said.
The best strategy by which to do this is through FNA of the thyroid nodule. If FNA results are suspicious, “you can always clarify them by getting a serum calcitonin level,” she added. The next step is to determine the extent of the disease present.
Here, basal calcitonin and CEA levels, both produced by the tumor, can be valuable tools to help surgeons determine how much disease is present. When calcitonin levels are under 40 pg/mL, the disease is usually confined to the thyroid.
On the other hand, if the calcitonin level is >100 pg/mL, “you need to start thinking about regional nodal disease; if it is >400 pg/mL, you need to start thinking about distant metastatic disease,” Sippel said. Neck ultrasound is standard of care to localize nodal disease in both differentiated thyroid cancer and MTC.
Additional imaging, whether it be CT or MRI scans, are necessary for those patients in whom distant metastatic disease is likely present and for whom, if found, “cure may no longer be the intent of your dissection,” Sippel noted. If patients have any sign of voice changes—hoarseness for example—they also may have involvement of the recurrent laryngeal nerve. Knowing the status of these nerves before surgery makes it easier to sacrifice the nerve should it be necessary to do so during surgery, she added.
“You absolutely have to test for pheochromocytoma preoperatively as well,” Sippel said, “as patients with an unrecognized pheochromocytoma could have a hypertensive crisis during the operation. If you get a positive diagnosis, that has to be dealt with first.”
Sippel noted too, that the diagnosis of MTC is rare enough that when made, patients need to be sent to an expert in thyroid surgery.
“Finding a surgeon with significant experience in dealing with both neck dissection as well as MTC is crucial because they understand what the appropriate preoperative evaluation is and what needs to be done operatively,” Sippel said. “And the more patients you can get to undetectable levels of calcitonin postoperatively, the more relieved the patient is, because achieving undetectable levels just saves a lot of work-up and angst for these patients.”
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