Charles J. Ryan, MD: Safety Considerations Regarding Treatment

Dr. Ryan says that enzalutamide and abiraterone are both safe for long-term therapy. There is more corticosteroid toxicity with abiraterone during long-term therapy (>1.5 years), while with enzalutamide, fatigue and malaise can be present in the short term.

CASE 1: Metastatic Castration-Resistant Prostate Cancer

Andrew S. is a 62-year-old real estate attorney from Tampa, Florida. He is an active golfer and church volunteer.

Patient underwent radical prostatectomy 4.5 years ago (at age 58 years).

• At diagnosis, the patient’s PSA level was 8.5 ng/mL and his Gleason score was 4+3 = 7; stage T1c
• Patient’s prior medical history is notable for prior smoking (quit 12 years ago), kidney stones, and hypertension (well controlled)
• Patient is currently on antihypertensives; liver function tests are normal

Postop PSA is undetectable. At 16 months postop, the patient’s PSA is 0.8 ng/mL; a repeat measurement is 0.9 ng/mL.

Patient receives radiotherapy (64-70 Gy in standard fractionation) without androgen deprivation therapy

One year after radiotherapy, the patient’s PSA level rose to 2.1 ng/mL; CT imaging shows a 3.2-cm lesion in an obturator and several retroperitoneal lymph nodes (LNs).

Combined androgen blockade (CAB) initiated with an LHRH agonist and bicalutamide

PSA nadirs at 0.65 ng/mL

Side effects of CAB noted, including hot flashes and weight gain

Following 22 months of CAB, the patient’s PSA again increases from 0.65 ng/mL to 1.1 ng/mL, and then to 3.2 ng/mL.

Testosterone is 20 ng/dL

Patient is asymptomatic

On CT scan, the prior LNs are unchanged

Bone scan is positive for multiple lesions in the pelvis

Bicalutamide is discontinued, and patient is enrolled in a clinical trial of an immunotherapy