PTH and osteosarcoma: Intermittent administration of PTH increases bone mass and strength.12 However, because of the potential risk of inducing osteosarcoma and the high cost, PTH use has been limited to 2 years and is considered a “second-line” medication reserved for patients with severe osteoporosis at high risk of fracture.13 The use of other antiresorptive osteoporosis medications is limited by their adverse effects.