Following surgery long-term thyroid replacement is essential. Unlikefollicular and papillary cancersthere is no need to suppress the TSH below the normal level.External beam radiation may be used if there is evidence of residual cancer in the neck, it reduces local recurrence but has no effect on survival.Because medullary cancer does not concentrate iodine, radioactive iodine is not used as it is ineffective.
Ideally following surgery there should be no residual tumour and an undetectable calcitonin level. This regrettably is a rare event. When the blood calcitonin rises (evidence of either a recurrence or extension of persisting disease) a variety of imaging tests may be performed (Ultrasound, CT, or sophisticated nuclear medicine scans). Despite a rising calcitonin it is more common than not that these tests are negative. In such circumstances a wait and see policy is appropriate.
If there is good evidence of removable local disease in the neck it is best removed, although beneficial effect on prognosis is unproven. Even though parathyroid or adrenal tumours have already been removed it must be remembered that these tumours can be multiple and can reappear at a later date. Repeat blood and urine tests must be done on a regular basis.