Hypercalcemia can be associated with nearly all malignancies, most commonly breast, lung, kidney, and multiple myeloma. It is less commonly seen in leukemia and lymphomas, and if present, indicates a poor prognosis.
The 4 major mechanisms for hypercalcemia of malignancy:
-Humoral: PHTrP-mediated (~80% of cases)
-Local osteoclastic osteolysis (~20% of cases)
-Extrarenal 1,25 OH-D (<1% of cases) (lymphomas*)
-Ectopic PTH production (<1% of cases) (very rare**)
Treat with Zoledronic Acid vs Pamidronate?
ZA is faster and lasts longer than pamidronate, but is more expensive, maybe more renal failure, has sparse data to support this, and RTCs were done without hard endpoints.