Multiple Endocrine Neoplasia Type 2 (MEN 2)
The ATA recommends lymph node dissection for patients meeting any one of the following criteria:
- Radiographic evidence of nodal disease.
- Basal calcitonin level greater than 40 pg/mL.
- A thyroid nodule greater than or equal to 5 mm.
Patients who have had total thyroidectomy will require lifelong thyroid hormone replacement therapy. The dosing of medication is age-dependent and treatment should be initiated based on ideal body weight. For healthy adults 60 years and younger with no cardiac disease, a reasonable starting dose is 1.6 to 1.8 �g/kg given once daily. Older patients may require 20% to 30% less thyroid hormone. Children clear T4 more rapidly than adults and consequently require relatively higher replacement by body weight. Depending on the age of the child, replacement should be between 2 to 6 �g/kg. It is important to note, however, that patients should be given replacement, rather than suppressive therapy. Since C-cell tumors are not TSH-dependent for growth, the T4 therapy for MTC patients therefore should be adjusted to maintain a TSH within the normal reference range.
There is no difference in survival between familial and sporadic forms of MTC when adjusted for clinicopathologic factors. Chemotherapy and radiation are not effective against this type of cancer,[3,140,141] although phase I and II clinical trials are ongoing at selected centers. (Refer to NCI's List of Clinical Trials for more information.)
Level of evidence: 5
Treatment for those with pheochromocytoma
Pheochromocytoma may be either unilateral or bilateral in patients with MEN 2. Laparoscopic adrenalectomy is the recommended approach by some authorities for the treatment of unilateral pheochromocytoma.[22,24] Two studies examined the value of a posterior retroperitoneoscopic adrenalectomy and found that it was safe and effective, with zero mortality, associated with a low rate of minor complications, and required conversion to open or laparoscopic lateral surgery in only 1.7%.[142,143] This approach appears to be a feasible and safe alternative to open or laparoscopic surgery, but extensive experience is needed.
In one series, 23 patients with a unilateral pheochromocytoma and a macroscopically normal contralateral adrenal gland were treated initially with unilateral adrenalectomy. A pheochromocytoma developed within the retained gland in 12 (52%) of these subjects, occurring a mean of 11.9 years after initial surgery. During follow-up subsequent to unilateral adrenalectomy, no patient experienced a hypertensive crisis or other problems attributable to an undiagnosed pheochromocytoma. In contrast, 10 (23%) of 43 patients treated with bilateral adrenalectomy experienced at least one episode of acute adrenal insufficiency; one of these patients died. Unilateral adrenalectomy appears to represent a reasonable management strategy for unilateral pheochromocytoma in patients with MEN 2,[145,146] when coupled with periodic surveillance (serum or urinary catecholamine measurements) for the development of disease in the contralateral adrenal gland.