Thyroid and Parathyroid Cancer

Diagnosis and Management of Thyroid Cancer

Thyroid carcinoma, which comprises the majority of endocrine malignancies, has a substantial annual morbidity and mortality based on age and other predisposing factors. Diagnosis of a growing thyroid nodule can be difficult, but ultrasonography, radionuclide scanning, and fine needle aspiration allow the majority of nodules to be properly characterized. Treatment of differentiated thyroid carcinoma remains controversial. Surgical resection continues to be the most important modality with long survival if the tumor is resected early. Newer imaging techniques have improved the diagnosis of locally recurrent or metastatic disease. Radioactive iodine ablation is indicated for patients with “high-risk” tumors or advanced age. Few patients respond to cytotoxic chemotherapy. In the past decade, advances in the screening and diagnosis of medullary thyroid carcinoma have led to earlier detection with improvement in survival.

Case report: long-term remission of parathyroid cancer: possible relation to vitamin D and calcitriol therapy

Recurrence of surgically treated parathyroid cancer occurs in 30% to 65% of patients and has a poor prognosis; only 1 of 29 cases remained normocalcemic more than 2 years later. No medical attempts to prevent recurrence have been reported. A 24-year-old pregnant woman whose mother died of parathyroid cancer underwent apparently successful surgery for parathyroid cancer. Serum Ca and parathyroid hormone (PTH) returned to normal levels but 3 months after surgery, although normocalcemic, the serum PTH level was elevated. The administration of vitamin D 200,000 U/month or calcitriol 0.5 microgram daily and 1 g of Ca supplementation daily, resulted in the normalization of PTH during 81 months of follow-up. On three occasions, when vitamin D or calcitriol were omitted, serum intact, C-terminal, or mid-molecule PTH levels rose. Ionized and total serum Ca, creatinine, calcitriol and calcidiol levels were normal, and multiple ultrasounds of the neck remained negative after surgery. This observation suggests that serum PTH could be an early marker for the detection of recurrence in parathyroid cancer with normal serum Ca, and that suppression of PTH secretion by vitamin D or calcitriol could avert or delay the progression of recurrence. Additional trials with calcitriol in operated normocalcemic parathyroid cancer with an elevated serum PTH level is recommended.