To investigate the efficacy and safety of radium-223 in combination with new-generation hormonal agents in patients with bone metastases of prostate cancer.

The clinical data of 17 patients (12 from the First Affiliated Hospital of Airforce Military Medical University and 5 from Xi'an International Medical Center Hospital) with metastatic castration-resistant prostate cancer(mCRPC) treated by radium-223 combined with new-generation hormonal agents from January 2021 to June 2022 were retrospectively analyzed. In all cases, the average age was (73.3±8.5) years old. Before treatment, the median prostate-specific antigen (PSA) was 15.7 (3.2, 36.5) ng/ml, the median alkaline phosphatase (ALP) was 131.5 (79.0, 430.7) U/L. All patients had ≥ 2 bone metastases but no visceral or lymph node metastases. The median number of bone scan lesions was 10(8, 15). Bone pain symptom was present in 16(94.1%) patients. There were 9 cases (52.9%) with Eastern Cooperative Oncology Group (ECOG) score of ≥2, 1 case (5.9%) with ECOG score of 1 and 6 cases (35.2%) with ECOG score of 0. All patients were treated with radium-223 (55 kBq/kg, injected every 4 weeks for a maximum of 6 cycles), of which 5 patients were combined with enzalutamide, 8 patients combined with apatamide and 4 patients combined with bicalutamide. PSA response (PSA decreased by ≥30% from baseline and maintained for at least 1 month), ALP response (ALP decreased by ≥30% from baseline and maintained for at least 1 month) and pain relief rates were analyzed. Imaging evaluation was performed before and after treatment to calculate the objective response rate of metastases. The incidence of treatment-related adverse effects and skeletal related event (SRE) were also recorded.

Eleven patients completed 6 courses, 3 patients completed 5 courses and 3 patients completed ≥4 courses. The median ALP after 1 month of last treatment was 83.2 (51.5, 126.5) U/L, which was significantly decreased than baseline. 12 patients (70.6%) showed an ALP response and the other 5 (29.4%) showed varying degrees of ALP elevation. PSA response was observed in 4 patients (23.5%), of which 2 (11.8%) had a continuous decrease and 2 (11.8%) had a late-stage increase in PSA. Pain relief was relieved in 15 cases (88.2%) during treatment, 1 case (5.9%) had worsening pain due to disease progression and 1 case (5.9%) had no change during treatment. The ECOG score decreased in 15 (88.2%) patients. The median number of bone metastases in patients decreased to 5 (4, 9). One patient (5.9%) had complete remission during treatment, 11 patients (64.7%) had a partial response, 4 patients (23.5%) were stable, and 1 (5.9%) showed imaging progression after 4 months of treatment. The overall objective remission response rate was 70.5% (12/17). Treatment-related hematologic adverse effects included anemia (1 case, 5.9%, grade 3), thrombocytopenia (1 case, 5.9%, grade 3) and leukopenia (1 case, 5.9%, grade 2). Non-hematologic adverse effects included fatigue (3 cases, 17.6%, 2 cases in grade 1, 1 case in grade 2), gastrointestinal bleeding (1 case, 5.9%, grade 3), diarrhea (1 case, 5.9%, grade 2) and fever (1 case, 5.9%, grade 1). Patients with grades 1 to 2 relieved with symptomatic management. Three cases (17.6%) were discontinued due to intolerance of grade 3 adverse reactions and 1 case (5.9%) terminated on its own. There was no SRE during treatment and follow-up.

Radium-223 combined with New-generation hormonal agents has a high objective remission rate in patients with mCRPC, which could provide pain relief and improve quality of life. The incidence of adverse reactions was low and well tolerated.

Prostatic neoplasms; Carcinoma; Bone metastasis; Radium-223; New-generation hormonal agents