Elderly men (>/=75yo) comprise 25% of patients with prostate cancer. However, they are typically underrepresented in pivotal trials. Limited data suggest these patients receive less intensive treatment with greater toxicity, despite comparable response rates. Our retrospective study examined treatment patterns and outcomes in a real-world population with castration-resistant prostate cancer (CRPC).
Using the multi-centre electronic CRPC Australian Database (ePAD), we extracted clinicopathologic, treatment and outcome data. Descriptive statistics were used to report data in patients aged >/=75yo and <75yo. Comparisons between these groups were analysed using T-tests and Fisher’s exact tests. Time-to-event analyses were performed using the Kaplan-Meier method.
We identified 753 men with CRPC, with 327 (43%) aged >/=75yo. Elderly patients had higher rates of ischemic heart disease (33% vs 16% in younger patients, p=0.004) and stroke (11% vs 5%, p=0.007). They were more likely to receive only one line of systemic therapy (67% vs 40%, p<0.001), and androgen receptor signalling inhibitors (ARSIs) were most commonly prescribed as initial therapy (78% vs 48%, p<0.001). Enrolment in clinical trials was less frequent (5% vs 15%, p<0.001). There was no statistical difference in treatment duration or PSA50 response rates with ARSIs or docetaxel (Table). Overall, serious adverse events (SAEs) leading to hospitalisation, dose delays or modifications occurred in more elderly men (24% vs 16%, p=0.003), with a trend towards greater SAEs in those receiving docetaxel or ARSIs. Elderly patients were more likely to stop docetaxel due to toxicity (39% vs 21%, p=0.02). First-line therapy for CRPC
<75yrs >/=75years p-value Abiraterone N=58 N=84 PSA50 response rate 24 (41%) 43 (51%) 0.30 Treatment duration 11.9 months 10.6 months 0.52 Serious adverse event 10 (17%) 24 (29%) 0.16 Cessation due to toxicity 6 (10%) 12 (14%) 0.61 Enzalutamide N=119 N=159 PSA50 response rate 63 (53%) 94 (59%) 0.33 Treatment duration 11.5 months 11.5 months 0.87 Serious adverse event 20 (17%) 36 (23%) 0.29 Cessation due to toxicity 8 (7%) 16 (10%) 0.39 Docetaxel N=155 N=41 PSA50 response rate 79 (51%) 18 (44%) 0.48 Treatment duration 6.0 months 4.6 months 0.24 Serious adverse event 28 (18%) 10 (24%) 0.38 Cessation due to toxicity 32 (21%) 16 (39%) 0.02
In our real-world cohort, elderly men had greater comorbidities and received fewer lines of systemic therapy. Although there was no difference in treatment response or duration, elderly patients experienced higher SAE rates. Prospective studies are required to further evaluate long-term outcomes in these patients.
The authors.
Astellas, AstraZeneca, Janssen, Amgen.
E. Kwan: Honoraria (self): Janssen; Honoraria (self), Travel/Accommodation/Expenses: Ipsen; Research grant/Funding (institution), Travel/Accommodation/Expenses: Astellas; Research grant/Funding (institution), Travel/Accommodation/Expenses: Pfizer; Research grant/Funding (institution): AstraZeneca; Research grant/Funding (institution): Bristol-Myers Squibb; Research grant/Funding (institution): Merck Serono. F.X. Parnis: Leadership role, Administrative Board: Janssen; Leadership role, Administrative Board: Astellas; Leadership role, Administrative Board: Bayer. All other authors have declared no conflicts of interest.