Key clinical point: High skeletal muscle mass may be associated with a lower risk for disease progression and mortality in patients with castration-resistant prostate cancer (CRPC), particularly in those treated with docetaxel.

Major finding: The high skeletal muscle index group had higher prostate-specific antigen progression-free survival (13.5 vs. 8.3 months; P = .030), radiologic progression-free survival (14.9 vs. 9.1 months; P less than .001), and overall survival (24.1 vs. 16.9 months; P = .015) than the low SMI group. Skeletal muscle mass was associated with the efficacy of docetaxel but not that of androgen receptor signaling inhibitors (ARSi).

Study details: The study analyzed records of patients with CRPC who received docetaxel (n = 144) or ARSi (n = 86) as first-line therapy.

Disclosures: The study was supported by a research grant from the National Cancer Center, Republic of Korea. The authors declared no conflicts of interest.

Commentary

“Body composition has been postulated to be associated with treatment outcomes in many cancers, including prostate cancer. However, the association is not well understood. In the accompanying study, Pak et al conducted a retrospective cohort study to determine whether there may be an association between body composition and survival and efficacy of first-line treatment in patients with castrate-resistant prostate cancer. CT scans obtained just prior to initial of docetaxel or androgen receptor signaling inhibitors (enzalutamide or abiraterone) were analyzed to determine the skeletal muscle index (SMI), visceral fat index (VFI), and subcutaneous fat index (SFI). Higher SMI was associated with higher PSA-based and radiologic progression-free survivals in patients receiving docetaxel, but not in patients receiving enzalutamide or abiraterone. While not practice-changing, incorporation of such body composition analyses may be useful as part of future prospective trials.”

Mark Klein, MD