Clinical features of bone metastasis with extraosseous soft-tissue mass in prostate cancer patients

Abstract

Objective: This study aimed to compare the differences in the clinical features of prostate cancer (PC) bone metastases (PCBMs) with and without extraosseous soft-tissue masses (ESTMs). Methods: Among 720 consecutive patients with histopathologically or clinically diagnosed PC, PCBMs were identified in 48 (7%) patients at initial diagnosis before receiving treatment. CT images of PCBMs were assessed and classified into two groups: PCBMs with and without ESTMs. Clinical features of PCBMs with and without ESTMs were compared. Results: We found ESTMs in 15 (31%) patients diagnosed with PCBMs, and 33 (69%) patients diagnosed with PCBMs did not have ESTMs. The initial prostate-specific antigen (PSA) levels (median, 1031 vs 247 ng ml−1; p < 0.05) and PSA reduction rates (median, 99.97 vs 99.40 %; p < 0.05) were significantly greater in PCBMs with ESTMs than in PCBMs without ESTMs. No significant differences were observed in terms of age, Gleason sum score, PSA nadir, time from the initiation of therapy to PSA nadir, PSA doubling time, PSA progression-free survival, or overall survival between patients having PCBMs with and without ESTMs. Conclusion: Both initial PSA levels and PSA reduction rates were higher in PCBMs with ESTMs than in PCBMs without ESTMs; however, no significant differences were observed in other clinical features. Advances in knowledge: ESTMs in patients with PCBMs were not a poor prognostic factor.