Efficacy and Safety of Brazilian Green Propolis in Biochemically Recurrent Prostate Cancer after Radical Prostatectomy: A Single-Arm Phase II Study

Background: Radiation or hormonal therapy is considered for prostate cancer patients with biochemical recurrence (BCR) after radical prostatectomy (RP). However, these therapies have their own complications. To delay the start of these therapies, we investigated the efficacy and safety of Brazilian green propolis for the treatment for BCR after RP. Materials and Methods: This single-center, single-arm open trial included 22 patients who experienced BCR after RP between 2016 and 2019. The patients received nine softgels of Brazilian green propolis (containing 40 mg propolis per capsule) daily for 6 months. The primary outcome was the prostate-specific antigen (PSA) response rate. The secondary outcomes included progression-free time, PSA slope (1/PSA doubling time) response rate, quality of life, and safety profile. Results: The PSA response rate was 0%. The mean PSA slopes before and after baseline were 0.12 month−1 and 0.08 month−1, respectively. Fifteen patients (68%) showed a decreased PSA slope after treatment. There were no negative effects on quality of life or serious adverse events leading to treatment discontinuation. Conclusion: There was no significant anticancer response in patients who received Brazilian green propolis. However, the PSA slope was decreased after propolis administration. Further, Brazilian green propolis may be safely consumed by patients.