Imaging Prostate Cancer
Posted: Nov 01, 2018
POSTED: April 10, 2017
Dr. Raoul Concepcion is the Director of The Comprehensive Prostate Center in Nashville, Tennessee and the past President of the Large Urology Group Practice Association (LUGPA.)
Prostatepedia spoke with him about approaches to bone metastases within urology groups.
Dr. Raoul Concepcion: Fortunately, the majority of prostate cancer diagnosed today tends to be low-risk and associated with lower Gleason grades. For those men, active surveillance may be an appropriate treatment option. The challenge now is not to just identify prostate cancer, but to identify significant prostate cancer: those at risk for dying of their disease if left untreated. If you have Gleason -3 + 3, what we are now calling Group Pattern 1, or Gleason 3 + 4 (Group Pattern 2), the recommendation is not to do a staging work up. The likelihood of finding metastatic disease is very low. But if you do pick up a higher-grade clone on biopsy in a Gleason 4 or 5 prostate cancer, that man should definitely undergo a staging workup—usually a CT scan and bone scan—to look for metastatic disease.
Bony metastases can be detected in a couple different phases of prostate cancer. Sometimes, bone metastases are found at initial diagnosis during staging work-up. This usually happens with higher-grade tumors. The second phase is when men progress past definitive therapy and adjuvant treatment to we now call metastatic castration resistant prostate cancer (mCRPC). After diagnosis, both low-grade and high-grade patients decide on prostate cancer management.
Lower-grade patients can choose active surveillance, radiation therapy, radical prostatectomy, or even focal therapies like cryotherapy.
Options for higher-grade patients could include multi-modality therapy of surgery, radiation therapy, and hormones. These patients are really the people at risk.
After an individual has been treated definitively for prostate cancer, we measure his PSA after therapy. If his PSA starts to go up again, he is said to have a biochemeical recurrence.
For the most part, these patients do not have symptoms. They’re not in pain. They don’t have significant fatigue. Again, these are patients who have been definitively treated and are currently not on therapy.
Once his PSA starts to go up, we start to look at the rapidity with which it goes up. We call this PSA kinetics, or doubling time. If there is a rapid doubling time in a man who had a higher grade Gleason Pattern at diagnosis, we know he has a higher risk of developing metastatic disease. We usually go ahead and get a scan when his PSA goes above 10. If that scan is still negative in a high-grade patient with a rapid doubling time, most urologists initiate androgen deprivation therapy.
Androgen deprivation therapy, or hormonal therapy, tries to drive down testosterone levels into castration range. If his PSA then starts to go up again, he now has, by definition, mCRPC. Again, these are patients with prostate cancer that has been definitively treated.
They have then gone on androgen deprivation therapy until their testosterone levels got to less than 50, and then their PSAs started to go up again.
That has never been really well defined. I participated in a consortium of academic and community urologists, medical oncologists, and radiation oncologists called the RADAR (Radiographic Assessments for the Diagnosis of Advanced Recurrence) working group chaired by Dr. E. David Crawford to answer just that question.
We recommended that in such patients we should go ahead and look for metastases with a bone scan, a CT scan, or some of the new advanced imaging techniques when the PSA gets to 2.
Dr. Concepcion: I think most urologists, unfortunately, extrapolate what they know about PSA in the early stages when patients aren’t on hormones to the castration resistant prostate cancer space.
If a patient had never been on hormones and his PSA is low, usually it means they don’t have a lot of disease. It’s become a real hurdle, an educational challenge, to get urologists to start thinking about that and not to wait until patients are symptomatic.
Dr. Concepcion: Yes, I think that would be very appropriate. Unless you’re being treated by a urologist with a lot of expertise… A lot of general urologists aren’t going to know about the RADAR recommendations.
Dr. Concepcion: It depends. Most urologists in community practices, especially in bigger groups, have their own CT scans. That part of the workup can be done in the urology office.
Technetium-based bone scans usually require a nuclear medicine department and are done in a hospital.
A lot of times, we’ll get a CT scan in our office and then coordinate with a freestanding imaging center or a hospital-based imaging center to get a nuclear medicine scan.
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