Cinacalcet (Sensipar) provides no measurable clinical benefits for patients with primary hyperparathyroidism and may accelerate bone loss with prolonged use.

BACKGROUND: Cinacalcet (Sensipar) has been shown to decrease calcium levels in patients with primary hyperparathyroidism (PHPT); however, few other endpoints have been studied and long-term effects are not known. METHODS: At the discretion of a referring doctor, 70 patients began Cinacalcet as an alternative to surgery for PHPT. Patients were followed as long as the drug was tolerated at which time all underwent parathyroidectomy. RESULTS: Before treatment, serum calcium levels averaged 11.7 ± 0.5 (range, 11.0-15.1) and PTH averaged 156 ± 42 (range, 88-815); 93% had two or more classic parathyroid symptoms (average, 5.3; range, 0-9). Cinacalcet was discontinued in 19 patients (26%) within 4 months because of nausea/vomiting. The remainder (n = 51) were treated from 8 to 28 months. Calcium levels decreased in all patients but remained variable. PTH levels decreased in 80% of patients but always remained elevated. Only 3 (6%) had symptom relief (p = 0.8), whereas 11 (21.6%) felt worse (p < 0.05). Twenty-three patients took Cinacalcet for >1.5 years, 14 of which showed significant (>1 SD) decreases in bone density (p < 0.05), and none had increases in bone density. All had curative outpatient parathyroid surgery followed by partial or complete resolution of symptoms within 3 months in 88% (p < 0.001). CONCLUSIONS: Cinacalcet reduces serum calcium but is not tolerated by many patients. Cinacalcet does not provide symptom relief of PHPT and more commonly increases subjective symptoms. Prolonged use is associated with continued bone loss in some patients, possibly due to persistent elevated PTH levels. With very few exceptions, pHPT can be cured via a quick outpatient operation, which remains the treatment of choice.

Intrathyroid parathyroid adenoma: incidence and location--the case against thyroid lobectomy.

OBJECTIVE: It has been taught that a missing parathyroid adenoma can be within the thyroid. Therefore, thyroid lobectomy is appropriate when an adenoma cannot be found. Unfortunately, this technique is often futile. The purpose of this study is to examine the frequency of unsuccessful thyroid lobectomy in parathyroid surgery and to look at the true incidence and location of intrathyroid parathyroid adenomas (iT-PAs). STUDY DESIGN: A retrospective chart review of 11,163 patients undergoing parathyroid surgery identifying the location of more than 40,000 parathyroid glands. SETTING: A tertiary care center specializing in parathyroid surgery. SUBJECTS AND METHODS: A total of 1163 reoperations for persistent primary hyperparathyroidism (PHPT) were examined for the incidence and outcomes of thyroid lobectomy performed to find iT-PA. A second study examined 10,000 patients undergoing first-time parathyroidectomy to classify the location and incidence of iT-PA. RESULTS: Thyroid lobectomy had been previously unsuccessfully performed in 77% cases of PHPT undergoing reoperation. Two or fewer glands were found in 82% prior to lobectomy. The adenoma was subsequently found on the lobectomy side in 64% and on the opposite side in 36%. True iT-PA occurred in only 0.7% of 10,000 primary cases. Another 1.2% were closely adherent to or partially within the thyroid substance. The most common location was the lower lateral quadrant of the thyroid. CONCLUSION: The incidence of true iT-PA is less than 1%, occurring in predictable locations. Thyroid lobectomy for a missing parathyroid adenoma is typically unsuccessful and should only rarely, if ever, be performed.