Infiltration of tumour-associated macrophages in prostate biopsy specimens is predictive of disease progression after hormonal therapy for prostate cancer

Abstract

Objective: • To evaluate tumour-associated macrophage (TAM) infiltration in prostate biopsy specimens as a possible prognostic factor for prostate cancer (PCa) after hormonal therapy.

Patients and methods: • Immunostaining of TAMs in prostate biopsy specimens was performed using a monoclonal antibody CD68 for 71 patients having PCa treated with hormonal therapy. • Six microscopic (×400) fields around the cancer foci were selected for TAM counting.

Results: • The median value of serum prostate-specific antigen (PSA) was 50.1 ng/mL, and the median TAM count was 22. • Recurrence-free survival was significantly better in patients with fewer TAMs (<22) than in those with higher numbers of TAMs (≥22) (P < 0.001). • TAM count was higher in those with higher serum PSA (PSA), higher Gleason score, clinical T stage or those with PSA failure. Cox multivariate analysis showed that TAM count is one of the prognostic factors for PCa treated by hormonal therapy (P < 0.0001).

Conclusion: • TAM infiltration in prostate needle biopsy specimens is a useful predictive factor for PSA failure or progression of PCa after hormonal therapy.