What treatment options would you consider for this patient and what approaches would you favor?
For a patient like this, first of all I’m going to consider whether or not I need to do something directly for the pain and that could be addressed perhaps with a focal treatment like radiation therapy, such as external beam radiation therapy, which can frequently be delivered in one or two treatments, and that might cause us to be able to gain control of the pain relatively rapidly. But that’s not going to be sufficient enough to control the disease in the long run, and in the long run he’s going to need systemic therapy. So the considerations are comorbid illness, overall performance status, and general degree of disease burden.
Now, in the abiraterone and the enzalutamide studies in which patients were chemotherapy-naïve, most of those patients were required to have a performance status of 0, 1, or 2, but they weren’t allowed to be symptomatic from their disease. The thinking at the time was that these are patients who should probably be treated with chemotherapy. But now that the data are out and we know that abiraterone and enzalutamide are considered standard approaches in this setting, I think that we can safely address the issue of giving a patient with pain a systemic treatment such as this.
Now, as I look at these two drugs, abiraterone and enzalutamide, one of the considerations are the differential side effects of the two. With abiraterone, we have the likelihood for hypertension, hypokalemia, and fluid retention, all of which are important considerations, especially in the elderly. Aside from that, the toxicities may be skin bruising from the prednisone and occasionally liver function abnormalities.
Enzalutamide, on the other hand, doesn’t have the prednisone issues associated with it and it doesn’t have quite as much fluid retention associated with it. However, we do see a significantly higher rate of fatigue with enzalutamide and that fatigue can be debilitating in some patients. My sense is that elderly patients may have a slightly harder time with that.
We also will occasionally see arterial hypertension or hypertension in those patients. And then finally one of the major concerns in an elderly patient with the use of enzalutamide would be falls or gait abnormalities and things related to central nervous system penetrance and toxicity of the drug. So, for this patient, for example, if I was worried that falls were a problem, I might steer away from enzalutamide. And, in fact, in my personal practice I generally use enzalutamide more in younger patients and abiraterone more in older patients.
CASE: Metastatic Prostate Cancer (Part 1)
Stanley S is an 83-year-old Caucasian male whose past medical history includes diagnosis of adenocarcinoma of the prostate in 2012 with no evidence of metastasis. At the time, he was started on bicalutamide and his serum PSA levels subsequently decreased to 1.2 ng/ml.
During his most recent follow-up exam, the patient complained of intermittent back pain and increasing fatigue.