Combining Computed Tomography-Based Bone Density Assessment with FRAX Screening in Men with Prostate Cancer

Andrew M McDonald; Joseph A Jones; Rex A Cardan; Kenneth S Saag; David L Mayhew; John B Fiveash

doi:10.1016/j.jocd.2016.04.011

Combining Computed Tomography-Based Bone Density Assessment with FRAX Screening in Men with Prostate Cancer

J Clin Densitom. 2016 Oct;19(4):430-435. doi: 10.1016/j.jocd.2016.04.011. Epub 2016 May 27.

Authors

Andrew M McDonald¹, Joseph A Jones², Rex A Cardan³, Kenneth S Saag⁴, David L Mayhew⁵, John B Fiveash³

Affiliations

¹ Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL, USA. Electronic address: ammcdonald@uabmc.edu.
² School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
³ Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL, USA.
⁴ Division of Rheumatology, University of Alabama at Birmingham, Birmingham, AL, USA.
⁵ Department of Radiation Oncology, Tufts University, Boston, MA, USA.

PMID: 27241940
DOI: 10.1016/j.jocd.2016.04.011

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 (L5_CT) 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. L5_CT values of 105 and 130 HU were used as screening thresholds. The clinical characteristics of additional patients identified by each L5_CT screening 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 L5_CT = 105 HU and L5_CT = 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 L5_CT threshold 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.

Keywords: Androgen deprivation therapy; FRAX; bone density screening; prostate cancer.

MeSH terms

Algorithms*
Bone Density*
Humans
Male
Middle Aged
Osteoporosis / diagnosis*
Osteoporotic Fractures / diagnosis
Osteoporotic Fractures / etiology
Prostatic Neoplasms / complications*
Prostatic Neoplasms / radiotherapy
Retrospective Studies
Risk Assessment / methods*
Tomography, X-Ray Computed*