CT for Bone Density, Muscle Mass and Noncancer Death in Prostate Cancer

Bone density and muscle mass measured by CT may predict noncancer death among men with localized prostate cancer, according to a study published in Radiology.

Researchers from the University of Alabama at Birmingham and Tufts University in Medford, MA, sought to determine if CT metrics of bone mineral density and muscle mass can improve the prediction of noncancer death in men with localized prostate cancer.

A total of 653 men participated in the trial, which took place between 2001 and 2012. The researchers documented height, weight, and past medical history and whether the subjects underwent CT, including the L4-5 vertebral interspace. The mean CT attenuation of the trabecular bone of the L5 vertebral body (L5HU) was measured on a single axial CT section obtained at the mid-L5 level. The height-normalized psoas cross-sectional area (Psoas_L4-5) was measured on a single CT section obtained at the L4-5 vertebral interface. Multivariable Cox proportional hazards models were used to assess effects on noncancer death. By using parameter estimates from an adjusted model, a prognostic index for prediction of noncancer death was generated and compared with age-adjusted Charlson Comorbidity Index (CCI) by using the Harrell c statistic. Prostate cancer risk grouping, androgen deprivation, race, age-adjusted CCI, L5HU, and Psoas_L4-5 were included in a multivariable model.

The results showed that the age-adjusted CCI, L5HU, Psoas_L4-5, and race were independent predictors of noncancer death. The prognostic index yielded a c value of 0.747 for the prediction of noncancer death versus 0.718 for age-adjusted CCI alone.

The researchers concluded that L5HU and Psoas_L4-5 were independent predictors of noncancer death, and the prognostic index that incorporated these measures with the CCI was associated with improved accuracy for prediction of noncancer death.