Roughly one-third of patients with adenocarcinoma will develop skeletal metastases. Lesions are “blastic” when enhanced osteoblast activity creates areas of bony sclerosis visible on x-rays. Blastic lesions are less prone to pathologic fracture and less aggressive than lytic lesions.
Prostate carcinoma typically causes purely blastic metastases; breast and lung carcinoma can present with blastic mets but more typically have lytic or mixed lesions. Metastases may even convert from lytic to blastic during a course of therapy.
Bone metastasis is a grave prognostic sign, with five-year survival under 20% independent of the primary diagnosis.