Lateral spine radiographs before androgen deprivation treatment detect a high incidence of undiagnosed vertebral fragility fractures in men with advanced prostate cancer.

Abstract

Baseline bone mineral density scanning in patients about to commence long-term androgen deprivation therapy for advanced/metastatic prostate cancer is reported to show a high incidence of osteoporosis and osteopenia. We investigated the incidence of existing spinal osteoporotic fractures in this population as this is known to be a risk factor for the development of treatment induced fractures. Since 2003 we performed lateral thoracolumbar x-rays on all patients before androgen deprivation therapy for prostate cancer. The heights of T4-L5 vertebral bodies were measured, then reanalyzed by the Eastell method to define grade 1 or worse grade 2 vertebral crush fractures. We used a morphometric algorithm including an age stratified random sample of men with normal thoracolumbar x-rays to quantitatively assess fractures. A total of 202 patients with prostate cancer underwent thoracolumbar x-rays before androgen deprivation therapy. Of the patients 61.9% had 1 or more grade 1 and 60.9% had 1 or more grade 2 wedge fractures. In addition, 46.5% of patients had 1 or more grade 1 and 44.6% had greater than 1 grade 2 biconcavity fractures. Finally 63.9% of patients had 1 or more grade 1 and 47.8% had 1 or more grade 2 compression fractures. With conventional reporting 72.4% of patients had no bony abnormality, 14.9% had 1 and 12.7% multiple vertebral crush fractures. Bone mineral density was significantly less in patients with fracture(s) vs those with no abnormality (p<0.001). Routine reporting identifies a high incidence of spinal fractures before commencing androgen deprivation therapy, but this is much greater when quantitative assessment is applied. Thoracolumbar x-rays identify the risk of treatment induced fracture and allow baseline comparison in individuals who experience back pain on androgen deprivation therapy. We advocate more routine adoption of baseline thoracolumbar x-rays in patients with prostate cancer.