Abstract 1770O
Background
RT + ltADT (18-36 months) is a standard-of-care in the treatment of HR/LA-PC. Efforts are ongoing to evaluate intensification of systemic therapy beyond ADT to further improve outcomes. We evaluated 5-year metastasis-free survival (MFS) rates in subgroups of patients (pts) with HR/LA-PC to define patients more likely to benefit from treatment intensification, and guide design and interpretation of adjuvant trials in HR/LA-PC.
Methods
IPD from patients with HR/LA-PC (as defined by any of the following 3 risk factors [RFs]: Gleason ≥8, ≥cT3, PSA >20; or cN1) treated with RT+ltADT in RCTs collated by ICECaP were pooled. 5-year MFS was calculated by Kaplan-Meier method in various risk-groups and by number of RFs. Multivariable Cox regression estimated hazard ratios (HR) for the 3 RFs and cN1 disease, stratified by trials and years of enrolment. MFS was defined as distant metastasis on conventional imaging or death from any cause.
Results
3604 pts with HR/LA-PC treated with RT+ltADT on 10 randomized trials between 1987-2016 were eligible. Median age was 68 and median PSA was 24 (IQR 12-48). 2602 (72%) were cT3/4, 1942 (54%) had Gleason 8-10 and 422 pts (12%) had cN1 disease. The HR for MFS was 1.5 (95% CI 1.4-1.7) for Gleason ≥8, 1.2 (1.1-1.4) for PSA>20, 1.2 (1.1-1.4) for cT3/T4, and 1.8 (1.5-2.1) for cN1. 5-year MFS (%, 95% CI) rate was 83 (81-85), 78 (75-80) and 77 (73-80) for pts with 1, 2 and 3 RFs respectively, and 68 (63-72) for cN1 disease. Table shows 5-yr MFS rates in various subgroups.
Table: 1770O
| 5-yr MFS (%, 95% CI) | Gleason 7 | Gleason 8-10 | ||
| Tx1-2 | T3-4 | Tx1-2 | Tx3-4 | |
| PSA <10 | - | 87 (82-91) | 82 (76-87) | 75 (69-80) |
| PSA 10-20 | - | 81 (75-85) | 84 (77-89) | 79 (73-83) |
| PSA >20 | 84 (79-87) | 80 (76-83) | 74 (67-79) | 77 (73-80) |
| cN1 | 76 (67-82) | 64 (58-69) |
Conclusions
Pts with HR/LA-PC treated with RT+ltADT who had ≥2 RFs or cN1 disease had 5-yr MFS rates <80% and are the ones most likely to benefit from treatment intensification. This will guide patient counselling and the design and interpretation of adjuvant trials in HR/LA-PC.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Sanofi; Dendreon; Janssen; Astellas/Pfizer; Bayer; PCF.
Disclosure
All authors have declared no conflicts of interest.
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