Roundtable

Management of Patients With Treatment-Resistant Metastatic Prostate Cancer


 

References

The VA telehealth system is amazing. For patients who need to monitor blood pressure regularly, it’s really nice for them to have those numbers come directly back to me in CPRS (Computerized Patient Record System). That has worked wonders for some of our patients to get them through therapy.

Mark Klein. What do you tend to use when the prostate cancer is progressing for a patient? And how do you determine that progression? Some studies will use PSA rise only as a marker for progression. Other studies have not used PSA rise as the only marker for progression and oftentimes require some sort of bone scan criteria or CT imaging criteria for progression.

Julie Graff. We have a limited number of treatment options. Providers typically use enzalutamide or abiraterone as there is a high degree of resistance between the 2. Then there is chemotherapy and then radium, which quite a few people don’t qualify for. We need to be very thoughtful when we change treatments. I look at the 3 factors of biochemical progression or response—PSA, radiographic progression, and clinical progression. If I don’t see 2 out of 3, I typically don’t change treatments. Then after enzalutamide or abiraterone, I wait until there are cancer-related symptoms before I consider chemotherapy and closely monitor my patients.

Imaging Modalities

Abhishek Solanki. Over the last few years the Hines VA Hospital has used fluciclovine positron emission tomography (PET), which is one of the novel imaging modalities for prostate cancer. Really the 2 novel imaging modalities that have gained the most excitement are prostate-specific membrane antigen (PSMA) PET and fluciclovine PET. Fluciclovine PET is based on a synthetic amino acid that’s taken up in multiple tissues, including prostate cancer. It has changed our practice in the localized setting for patients who have developed recurrence after radiation or radical prostatectomy. We have incorporated the scan into our workup of patients with recurrent disease, which can give us some more information at lower PSAs than historically we could get with CT, bone scan, or magnetic resonance imaging.

Our medical oncologists have started using it more and more as well. We are getting a lot of patients who have a negative CT or bone scan but have a positive fluciclovine PET. There are a few different disease settings where that becomes relevant. In patients who develop biochemical recurrence after radiation or salvage radiation after radical, we are finding that a lot of these patients who have no CT or bone scan findings of disease ultimately are found to have a PET-positive lesion. Sometimes it’s difficult to know how best to help patients with PET-only disease. Should you target the disease with an oligometastasis approach or just pursue systemic therapy or surveillance? It is challenging but more and more we are moving toward metastasis-directed therapy. There are multiple randomized trials in progress testing whether metastasis-directed therapy to the PET areas of recurrence can improve outcomes or delay systemic ADT. The STOMP trial randomized surveillance vs SBRT or surgery for patients with oligometastatic disease that showed improvement in biochemical control and ADT-free survival.13 However this was a small trial that tried to identify a signal. More definitive trials are necessary.

The other setting where we have found novel PET imaging to be helpful is in patients who have become castration resistant but don’t have clear metastases on conventional imaging. We’re identifying more patients who have only a few sites of progression, and we’ll pursue metastasis-directed therapy to those areas to try to get more mileage out of the systemic therapy that the patient is currently on and to try to avoid having to switch to the next line with the idea that, potentially, the progression site is just a limited clone that is progressing despite the current systemic therapy.

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