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The role of imaging before surgery for patients with medullary thyroid cancer relies heavily on the initial calcitonin level. Additionally, this level can be used to suggest prognosis and an appropriate surgical procedure.
In some cases, believes Eric J. Sherman, MD, imaging can be reserved until after surgery. However, utilizing imaging before surgery helps determine nodal involvement, distribution, and the presence of mediastinal disease, notes Lori J. Wirth, MD. Ultrasounds are often utilized before surgery but often miss high retropharyngeal, deep paratracheal, and mediastinal lymph node involvement.
The decision concerning whether to utilize ultrasound, CT, or MRI can be guided by the calcitonin level, explains R. Michael Tuttle, MD. If levels are 30 or 40 with a small nodule, imaging may not be necessary. However, if levels are in the hundreds, lymph node involvement is more likely, requiring a CT scan or MRI of the neck and chest to ensure the proper surgical procedure is performed. Steven I. Sherman, MD, adds that if the calcitonin level is around 500, cross-sectional imaging of the neck, chest, and liver should be performed prior to surgery to diagnose distant disease.
In addition to staging, calcitonin levels may help indicate prognosis and whether a cure is possible, remarks Tuttle. If levels are 3,000 to 5,000 a biochemical cure is unlikely. In these situations, it may be appropriate to bypass a surgery, to avoid unneeded comorbidities.