Philip Kantoff, MD: Additional Treatment Options Following Immunotherapy

Dr. Kantoff addresses additional treatment options, which include other hormonal agents, including nilutamide, enzalutamide, and abiraterone. There appears to be cross-resistance at least between enzalutamide and abiraterone. Studies have shown that if you use abiraterone and then subsequently use enzalutamide, enzalutamide does not work as well as when you use enzalutamide up front. Similarly, if you use enzalutamide first and then try abiraterone, abiraterone does not work as well as it does up front.

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