Endocrine Abstracts

Introduction: Treatment with Cinacalcet results in decreased uptake of radiopharmaceutical (because of decreased secretory activity of parathyroid glands as shown by previous studies in secondary hyperparathyroidism). This effect has not been studied in patients with primary hyperparathyroidism (PHPT).

Objective: Evaluate clinical and MIBI scintigraphy uptake changes of adenomas in patients treated with Cinacalcet.

Patients and methods: We collected data from patients between years 2009 and 2013. We evaluated demographic and analytical parameters. Scintigraphy changes (qualitatively and semiquantitatively) of 16 patients (four patients have a negative one). We determined: uptake rate (%) mean and maximum uptake images during early (15 min of contrast administration) and late (2 h) and reassessed after treatment with Cinacalcet, minimum period of 3 months.

Results: 27 patients receive treatment with Cinacalcet, ten men and 17 women, diagnosis age 65 years. Initial profile: calcium, 11.34±1.12 mg/dl; phosphorus, 2.62±0.38 mg/dl; and PTHi, 260.96±190.04 pg/ml. Dose 30 mg in 80 and 60 mg in 20%. We found significant decrease in calcium (P<0.001) and PTH levels (P<0.05). After treatment, calcium 9.62±1.19 mg/dl, phosphorus 2.77±0.63 mg/dl; and PTHi, 119.9±179.41 pg/ml. One patient discontinue because of intolerance.

Qualitative scale 75% of analyzed patients decreased uptake on the scan performed after treatment, 12% obtained same. One case negative in baseline scan then located adenoma in post-treatment scan. Quantitative scale shows a trend to statistical significance but no differences between pre- and post-assessments, maximum and mean or early and late phase uptake.

Conclusions: Treatment with Cinacalcet is effective reducing calcium levels in PHPT patients. Cinacalcet seems to decrease scintigraphy uptake of parathyroid adenomas in patients with PHPT. Further studies should evaluate the clinical relevance of this finding.