Treatment patterns and outcomes for younger patients with metastatic castration-resistant prostate cancer (mCRPC); An Australian prospective registry study.

[INTRODUCTION AND OBJECTIVES] There is an increasing incidence of cancer in younger patients, including prostate cancer. Cancers developing in younger patients are reported to have a more aggressive phenotype. There is a need to examine younger patients with metastatic castration-resistant prostate cancer (mCRPC).

[METHODS] Analysis of the prospectively collected, multisite, electronic Prostate Cancer Australian Database (ePAD) was conducted to identify all mCRPC patients enrolled between June 2016 and March 2024. We defined patients diagnosed aged < 55 years as younger patients (YP) and compared their characteristics, treatment patterns and outcomes to the other patients aged ≥ 55 years (OP).

[RESULTS] Of 915 patients with mCRPC, 59 (6%) were YP. De-novo metastatic presentation, Gleason score, presence of liver metastasis and PSA doubling time at mCRPC were similar between YP and OP. In the mCRPC setting, first line treatment with docetaxel (19% YP vs. 21% OP; P = .72) and ARPI (68% YP vs. 74% OP; P = .31) was also similar. YP were more likely to receive ≥ 3 lines of therapy for mCRPC (37% YP vs. 23% OP; P = .016). There was no significant difference in overall survival from start of first line therapy (median 41.9 m YP vs. 35.1 m OP; HR 0.73; 95% CI, 0.47-1.15; P = .17) or time-to-treatment discontinuation for ARPI (median 15.8 m YP vs. 14.9 m OP; HR 0.93; 95% CI, 0.61-1.42; P = .75). Age < 55 was not independently associated with survival on multivariable analysis (HR 0.82; 95% CI, 0.52-1.29; P = .38).

[CONCLUSION] Young patients with prostate cancer who go on to develop mCRPC do not appear to have distinct clinical outcomes to other patients.