End-of-life Androgen Deprivation Syndrome With Enzalutamide in Metastatic Prostate Cancer: A Case Report.

Background/aim: Enzalutamide is a highly effective anti-androgen for the treatment of prostate cancer. Therapy can incur unbearable fatigue in elderly patients, which might require a reduced dosage. However, the value of reduced-dose treatment to improve the long-term tolerability and to decrease the risk of toxicity remains unknown.

Case report: We present the six-year clinical course of a patient treated upfront with low-dose enzalutamide (25% of the standard dose). Despite initial disease control and tolerance, the patient developed progressive frailty and signs of severe androgen deprivation near end-of-life.

Conclusion: This case illustrates that while low-dose enzalutamide can provide durable disease control in elderly patients with metastatic castration-resistant prostate cancer, it does not fully prevent the late-onset toxicities associated with androgen deprivation. Personalized treatment strategies - including dose adjustment over time and consideration of intermittent therapy - may help to balance efficacy with quality of life.