Effect of body composition parameters, including sarcopenia, myosteatosis, and adipose tissue, on overall survival of patients with mCRPC receiving 177 Lu-PSMA PRRT.

Purpose: This study aimed to examine the role of computed tomography (CT)-derived myosteatosis, sarcopenia, and other body composition parameters on overall survival (OS) in patients with metastatic castration-resistant prostate cancer (mCRPC) scheduled to receive lutetium (Lu)-177 treatment.

Material and method: Patients with mCRPC who underwent 68 Ga-prostate-specific membrane antigen (PSMA) PET/CT imaging before [ 177 Lu]Lu-PSMA-617 treatment and received at least two cycles of Lu-177 PSMA treatment between March 2017 and March 2023 were retrospectively reviewed in this study. Body composition including psoas muscle, skeletal muscle, subcutaneous adipose tissue, and visceral adipose tissue were evaluated at the third lumbar spine vertebra on CT axial sections.

Results: Median age of the 76 patients enrolled in this study was 75 years (59-91 years), and the median Gleason score was 8 (6-10). All patients received two to six (median 4) cycles of 7.4 GBq Lu-177 PSMA treatment at 6-8 week intervals. Upon univariant Cox regression analysis, subcutaneous adipose tissue index, right psoas myosteatosis, left psoas myosteatosis, and skeletal muscle index were determined to be prognostic factors for OS ( P  = 0.03, P  = 0.02, P  < 0.001, and P  = 0.04, respectively). However, the left psoas myosteatosis value was an independent prognostic factor for OS as determined by multivariant Cox regression analysis ( P  < 0.001).

Conclusion: Sarcopenia and myosteatosis before treatment were associated with shorter survival in mCRPC patients who were scheduled for Lu-177 PSMA treatment. Patients with left psoas myosteatosis value ≤26.85 HU had shorter OS, and we showed that OS is an independent prognostic factor.