Baseline Patient Demographics and Clinical Characteristics
| Parameter | Total cohort (n = 122) | bPSMA group (n = 18) | bCT group (n = 104) | P |
|---|---|---|---|---|
| Age (y) | 73.1 (65.2–78.3) | 70.8 (63.7–76.2) | 73.2 (65.7–78.6) | 0.392 |
| Gleason score ≥ 8 | 80 (65.6) | 12 (66.7) | 68 (65.4) | 0.957 |
| Gleason score missing | 1 (0.8) | 0 (0) | 1 (1.0) | |
| ECOG performance score | ||||
| ECOG 0 | 51 (41.8) | 8 (44.4) | 43 (41.3) | 0.161 |
| ECOG 1 | 53 (43.4) | 5 (27.8) | 48 (46.2) | |
| ECOG 2 and 3 | 18 (14.8) | 5 (27.8) | 13 (12.5) | |
| Prior SRE | 55 (45.1) | 11 (61.1) | 44 (42.3) | 0.139 |
| Prior life-prolonging drugs | ||||
| Enzalutamide or abiraterone | 97 (79.5) | 15 (83.3) | 82 (78.8) | 0.663 |
| Docetaxel | 74 (60.7) | 6 (33.3) | 40 (38.50 | 0.679 |
| Cabazitaxel | 18 (14.8) | 11 (61.1) | 63 (60.6) | 0.966 |
| 177Lu-PSMA radioligand therapy | 1 (0.8) | 0 (0) | 1 (1.0) | 0.676 |
| None | 12 (9.8) | 2 (11.1) | 10 (9.6) | 0.844 |
| Time mCRPC to 223Ra (mo) | 21.4 (10.4–41.6) | 20.2 (7.4–46.2) | 21.8 (10.5–41.6) | 0.724 |
| Time since start last treatment to 223Ra (mo) | 10.5 (6.9–16.0) | 11.5 (5.6–16.7) | 10.4 (6.9–15.9) | 0.910 |
| Time since start last treatment to 223Ra missing (mo) | 20 (16.4) | 3 (16.7) | 17 (16.3) | |
| Time baseline imaging to 223Ra (mo) | 0.89 (0.66–1.58) | 1.02 (0.74–1.77) | 0.84 (0.67–1.57) | 0.154 |
| Hemoglobin (mmol/L) | 7.8 (7.3–8.3) | 7.9 (7.4–8.3) | 7.8 (7.3–8.3) | 0.908 |
| Lactate dehydrogenase (U/L) | 233.5 (204.0–280.0) | 222.5 (202.8–259.8) | 236.0 (206.0–287.3) | 0.494 |
| ALP (U/L) | 142 (102.0–233.5) | 136.0 (91.0–179.3) | 143.5 (102.8–241.8) | 0.495 |
| PSA (ng/mL) | 87.9 (29.4–256.3) | 99.5 (31.8–206.3) | 85.4 (27.4–257.5) | 0.718 |
| Lymph node metastases (≥15 mm) | 17 (13.9) | 3 (16.7) | 14 (13.5) | 0.717 |
| Extent of bone metastases | ||||
| Low volume (<6 metastases) | 15 (12.3) | 4 (22.2) | 11 (10.6) | 0.655 |
| Intermediate volume (6–20 metastases) | 33 (27.0) | 2 (11.1) | 31 (29.8) | |
| High volume (>20 metastases) | 62 (50.8) | 12 (66.7) | 50 (48.1) | |
| Superscan | 12 (9.8) | 0 (0) | 12 (11.5) | |
| No. administered 223Ra injections | ||||
| 1 − 3 | 22 (18.0) | 2 (11.1) | 20 (19.2) | 0.694 |
| 4 and 5 | 23 (18.9) | 4 (22.2) | 19 (18.3) | |
| 6 | 77 (63.1) | 12 (66.7) | 65 (62.5) | |
| Cause of discontinuation* | ||||
| End of therapy | 77 (63.1) | 12 (66.7) | 65 (62.5) | 0.649 |
| Progression of disease | 28 (23.0) | 3 (16.7) | 25 (24.0) | |
| Myelotoxicity | 10 (8.2) | 2 (11.1) | 5 (4.8) | |
| Other | 7 (5.7) | 1 (5.6) | 9 (8.7) | |
| Death | 0 (0) | 0 (0) | 0 (0) | |
| Opioid use | 55 (45.1) | 7 (38.9) | 48 (46.2) | 0.567 |
| Bone health agent use | 82 (67.2) | 11 (61.1) | 71 (68.3) | 0.550 |
| Denosumab† | 57/82 (69.5) | 7/11 (63.6) | 50/71 (70.4) | |
| Bisphosphonates† | 25/82 (30.5) | 4/11 (36.4) | 21/71 (29.6) |
↵* Data summarized according to most important reason for discontinuation, with progression of disease being most important followed by myelotoxicity. Other causes of discontinuation included pain, SRE, adverse events, and patient wish.
↵† Data are number and valid percentage. Valid percentage is calculated percentage in case of subgroup analyses.
ECOG = Eastern Cooperative Oncology Group.
Qualitative data are number and percentage. Continuous data are median and interquartile ranges.