How likely is it to be diagnosed with an aggressive form of prostate cancer that has spread to the bones?
It is unusual. In nine out of 10 people diagnosed with prostate cancer, we either diagnose a low-risk disease or a high-risk disease, but we catch it early. Because of the PSA (prostate-specific antigen) tests and the exams we do regularly on these patients, approximately 7% of people present with an aggressive and metastatic disease, not organ confined, which is an advanced stage.
How do you learn if cancer has spread to the bones?
With a PET (positron emission tomography) scan, which is a test where someone ingests a radioactive tracer that shows areas where cancer has spread. Over the past two years, we have started to use a very sensitive prostate-specific membrane PET scan, or PSMA scan, that specifically looks for prostate cancer in the whole body, including the bones. It lights up like a candle on the scan, and it very accurately depicts metastatic disease.
What does hormone-sensitive prostate cancer mean in terms of treatment?
Hormonal treatment, in effect, means castration. It means we're going to cut the testosterone production from the body. We used to do that by orchiectomy, or removal of the testicles, which produce about 90 percent of the testosterone in the male body. More recently, we have developed hormonal blockade injections that mimic testosterone and shut down testosterone production biochemically, so you don't have to do the surgery.
Now, this is not a cure. This is not a treatment that is expected to cure hormone-sensitive prostate cancer. Most prostate cancers, if not all of them, will convert to a hormone-resistant status eventually — some within six months, some within five years. After that, no treatment will work. There are studies on different chemotherapies, radioactive therapies, and immunotherapies, but none of them have shown more than a 10% to 20% response rate.
Is surgery an option once it has metastasized to the bones?
No. You cannot remove it from the bone, so it's not going to have a lot of effect removing the prostate at this stage.
Is there a way to treat the metastasis, outside of the hormonal blockade therapy?
Some people use radiation, with very mixed results.
Can age change anything in terms of treatment?
Yes, because once you get into the realm of advanced, metastatic disease, we're talking about aggressive treatment. These aggressive treatments have a lot of side effects that not everybody can tolerate. The younger you are, the better your immune system is, and the better you will respond to more aggressive treatment. Age is an important factor when we are deciding what treatment to use.
What are the current guidelines for prostate cancer screening?
For people at normal risk, the American Cancer Society recommends a PSA test, which is a blood test, once a year beginning at age 50. Those at higher risk, including African American men and men who have close family members who have been diagnosed with prostate cancer, should talk with their primary care doctors about potentially getting screened even earlier.
What exactly is the PSA test measuring? What is prostate-specific antigen?
Prostate-specific antigen is a protein produced specifically by the prostate, but it's not specifically tied to cancer. It is specific to the prostate, but it can go up for three reasons: enlarged prostate; prostate inflammation, or prostatitis; and prostate cancer. The challenge we have is that the number doesn't always tell you which of the three is driving the PSA up. I have a lot of patients who have low PSA, and they do have cancer. I have a lot of patients who have high PSA, and I repeatedly do biopsies, and they have no cancer. They just have enlarged prostates or prostatitis.
→ Explaining PSA numbers.
If someone has a high PSA, is the next step a biopsy to determine if they actually have cancer?
Not necessarily. We usually do an MRI and discuss the history of PSA. If someone has had a PSA of 5 or 10, which is considered a bit high, for the past 20 years, and it hasn’t changed, this is not cancer. I'm not going to rush to do a biopsy on this guy. I would probably do an MRI first.
On the other hand, the patient who went from 1 to 3 within six months, without symptoms to explain it, I would definitely recommend a biopsy. It's a very individual decision-making process, not just a number that we look at and decide what to do.
Is there anything new in the treatment for prostate cancer?
There is always something new. We at the university have started doing focal laser ablation, which uses laser energy to destroy tumor cells. We use the NanoKnife, which destroys cancer cells with electrical pulses. I did the first laser treatment here for prostate cancer with MRI guidance. We're just starting to use the TULSA (transurethral ultrasound ablation) procedure, which uses ultrasound, delivered through the urethra, to destroy prostate tissue. I just got trained on that one, and hopefully we can have the machine here very soon to start treating patients.
All these treatments are for confined early-stage prostate cancer, and the idea is to prevent complications of treatment like radical surgery and radiation, which can be devastating.
Photo credit: The White House
