Effect of muscle density in patients with metastatic prostate cancer administered androgen deprivation therapy.

INTRODUCTION

Sarcopenia is a syndrome characterized by the loss of muscle mass and strength. The study objective was to determine the association between muscle density and overall survival (OS) in patients with metastatic onset prostate cancer (MPCa).

MATERIALS AND METHODS

This was a retrospective study of patients diagnosed with MPCa between 2009 and 2015 who received androgen deprivation therapy alone as initial treatment. Muscle density was calculated using the Hounsfield Unit Average Calculation (HUAC) in both psoas muscles in the computed tomography (CT) scan performed for diagnosis.

RESULTS

A total of 59 patients diagnosed with MPCa, with a mean age of 57.5±72.47 years, were found. Median prostate-specific antigen (PSA) level at diagnosis was 68.25 ng/dL (IQR 37.26-290). Gleason scores≥8 were recorded in 90.75% of the patients, bone metastases in 88.13%, and visceral metastases in 10.16%. Median HUAC was 20.32 HU (IQR 15.46-22.83). In a univariate analysis, the number of bone metastases, the presence of visceral metastases, and testosterone levels≥50 ng/dL at follow-up were associated with poorer OS, while high HUAC levels were associated with better OS. In a multivariate analysis, the number of bone metastases [hazard ratio (HR)=1.573, 95% confidence interval (CI)=1.103-2.243, p=0.012], the presence of visceral metastases (HR=7.404, CI=2.233-24.549, p=0.001), and the Gleason score (HR=2.001, CI=1.02-3.923, p=0.044) were associated with greater overall mortality, and HUAC (HR=0.902, CI=0.835-0.973, p=0.008) was associated with better OS.

CONCLUSIONS

In our series, increased HUAC values in the psoas muscles, as a reflection of muscle density, when MPCa was diagnosed had a protective effect on OS in these patients.