Cinacalcet for Hypercalcemia Caused by Pulmonary Squamous Cell Carcinoma Producing Parathyroid Hormone-Related Peptide

BACKGROUND: Current treatments for hypercalcemia caused by lung cell carcinomas producing parathyroid hormone-related peptide (PTH-rp) have limited efficacy, probably because of their lack of effect on PTH-rp secretion. In this case study we explored the efficacy of the calcimimetic cinacalcet as suppressor of PTH-rp production. PATIENT: A 57-year-old male with severe and recurrent hypercalcemia induced by a PTH-rp-producing squamous cell lung carcinoma, stage cT4N3M1b, poorly responding to standard treatments. RESULTS: Serum PTH-rp levels were not affected by saline, calcitonin or zoledronate. PTH-rp decreased during chemotherapy and cinacalcet monotherapy. The combination of chemotherapy plus cinacalcet was most effective in rapidly reducing serum calcium and PTH-rp. CONCLUSION: This case study is the first to suggest that cinacalcet may be of value in some cases of PTH-rp-dependent hypercalcemia. Corroborative evidence is needed.