title: Combining Computed Tomography-Based Bone Density Assessment with FRAX Screening in Men with Prostate Cancer.
abstract: To investigate the addition of a computed tomography (CT)-based method of osteoporosis screening to FRAX without bone mineral density (BMD) fracture risk assessment in men undergoing radiotherapy for prostate cancer, we reviewed the records of all patients with localized prostate cancer treated with external beam radiotherapy at our institution between 2001 and 2012. The 10-yr probability of hip fracture was calculated using the FRAX algorithm without BMD. The CT attenuation of the L5 trabecular bone (L5CT) was assessed by contouring the trabecular bone on a single CT slice at the level of the midvertebral body and by averaging the Hounsfield units (HU) of all included voxels. L5CTvalues of 105 and 130 HU were used as screening thresholds. The clinical characteristics of additional patients identified by each L5CTscreening threshold value were compared to patients whose estimated 10-yr risk of hip fracture was 3% or greater by FRAX without BMD. A total of 609 patients treated between 2001 and 2012 had CT scans available for review and complete clinical information allowing for FRAX without BMD risk calculation. Seventy-four (12.2%) patients had an estimated 10-yr risk of hip fracture of 3% or greater. An additional 22 (3.6%) and 71 (11.6%) patients were identified by CT screening when thresholds L5CT= 105 HU and L5CT= 130 HU were used, respectively. Compared to the group of patients identified by FRAX without BMD, the additional patients identified by CT screening at each L5CTthreshold level tended to be younger and heavier, and were more likely to be African-American or treated without androgen deprivation therapy. These results suggest that the addition of CT-based screening to FRAX without BMD risk assessment identifies additional men with different underlying clinical characteristics who may be at risk for osteoporosis and may benefit from pharmacological therapy to increase BMD and reduce fracture risk.
authors.affiliation: Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL, USA. Electronic address: ammcdonald@uabmc.edu.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: McDonald
authors.affiliation: School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Jones
authors.affiliation: Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: Rex A
authors.initials: RA
authors.lastname: Cardan
authors.affiliation: Division of Rheumatology, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: Kenneth S
authors.initials: KS
authors.lastname: Saag
authors.affiliation: Department of Radiation Oncology, Tufts University, Boston, MA, USA.
authors.forename: David L
authors.initials: DL
authors.lastname: Mayhew
authors.affiliation: Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: John B
authors.initials: JB
authors.lastname: Fiveash
mesh_terms: D000465:Algorithms; D015519:Bone Density; D006801:Humans; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000175:diagnosis*; D058866:Osteoporotic Fractures / Q000175:diagnosis / Q000209:etiology; D011471:Prostatic Neoplasms / Q000150:complications* / Q000532:radiotherapy; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D014057:Tomography, X-Ray Computed
keywords: Androgen deprivation therapy; FRAX; bone density screening; prostate cancer