A 69-year-old man reports increasing pain in the right leg. Physical examination reveals warmth and anterolateral bowing of the right shin. The serum alkaline phosphatase level is 260 U per liter (normal, 38 to 126 U per liter). A skeletal scintigraphic scan reveals enhanced uptake in only the deformed tibia, where a radiograph shows changes indicative of Paget's disease. His sister, whose alkaline phosphatase level is 160 U per liter, has asymptomatic Paget's disease confined to the left iliac wing. How should their conditions be managed?