About Prostate Cancer
Some people have never heard of a prostate, and even fewer know what it does. Yet, prostate cancer is the second leading cause of cancer death among men in the US, so its seriousness cannot be overstated. The purpose here is to provide a basic foundation of knowledge about the prostate and prostate cancer, and then try to provide a balanced view of common treatment options from my perspective.
The prostate is an organ found only in men. It secretes a fluid that feeds sperm. A tube called the urethra runs from the urinary bladder, through the prostate, to the penis. So when the prostate enlarges as we get older, the urethra gets compressed making it difficult to urinate.
Running within a few millimeters or a tenth of an inch from the edge of each side of the prostate is a delicate structure called the neurovascular bundle. These two bundles are vital for obtaining and maintaining an erection. Because the nerves are so delicate (only 1-2 mm in size) and run so close to the prostate, treating the cancer without destroying the nerves is a challenge. Precision down to the millimeter is crucial to maintain good sexual function.
What is Prostate Cancer and How is it Graded?
I would give all prostate cancers an F, but I’m getting ahead of myself.
Fundamentally, cancer occurs when cells stop respecting their neighbors. They keep multiplying even when there are already too many of them. This occurs because of changes or mutations in their DNA.
After we take a biopsy, a pathologist looks at the cells under a microscope to determine how aggressive the tumor looks, and then assigns numbers that determine the Gleason Score. The Gleason score has two numbers. The first number describes what most of the cancer looks like, and the second number describes what the rest looks like. So if the cancer is mainly a 4 but also has some 3, the Gleason score is 4+3. Because 4 is worse than 3, a Gleason 4+3 is worse than a Gleason 3+4. Sometimes these scores are simplified by adding the two numbers together (e.g., Gleason 6 or Gleason 7). Gleason 6 and above is considered cancer.
How is Prostate Cancer Treated?
Historically, the main treatment option for healthy patients was a radical prostatectomy. This is a major surgery with a significant recovery time and carries high risks of impotence and urinary incontinence. Twenty to thirty years ago, when a woman had a lump of breast cancer, she would get a radical mastectomy, with all the damage that comes from it. Breast surgeons have figured out that if all she has is a lump of breast cancer, all she needs is the lump to be removed (a lumpectomy), which is far less traumatic than radical surgery.
MRI guided focal laser ablation is like a lumpectomy for the prostate. The cancer is ablated (destroyed with heat), without undergoing radical surgery and minimizing damage to the neurovascular bundle and urethra. The patient goes home a few hours after the procedure. Many of our patients have told us that two days after the procedure, they were back to normal. We perform our ablations under conscious sedation (carefully monitored, powerful intravenous pain and anxiety medications) to minimize pain and anxiety. In my opinion, there are three main benefits of using laser over other focal therapies:
1) Studies have shown that our laser is extremely precise, down to 1 mm
2) MRI guidance allows us to see the tumor to precisely guide where we place the laser
3) MRI thermometry gives real time heating information to allow the physician to protect vital structures.
For more information, please go to the Focal Laser Ablation page.
External beam radiation therapy has the benefit of treating the entire prostate gland without an invasive surgery, but it also treats/damages the tissue around prostate. As a result, there are often effects of erectile dysfunction, difficulty urinating from damage to the urethra, and sometimes difficult to treat chronic diarrhea from damage to the rectum (which sits just behind the prostate). Radiation therapy also produces tremendous scarring and abnormal blood vessels, which makes additional therapy (if needed) more challenging and risky.
Cryotherapy or cryoablation is a way of freezing the cancer to destroy it. The zone of ablation is larger than with laser, which is good and bad. For some larger cancers that are not good candidates for laser, this allows cryotherapy to be a reasonable treatment option. Cryotherapy does not have anywhere near the precision of laser and will usually destroy the neurovascular bundle. Cryoablation also requires general anesthesia and not uncommonly a hospital stay.
High intensity focused ultrasound (HIFU) uses ultrasound instead of laser to heat the tissue. I performed 3D ultrasound imaging research as an undergraduate research fellow at Duke University while studying biomedical engineering, so I believe I can speak with some authority on the physics of HIFU and why I think laser is better. To obtain the 16 mm ablation diameter of the laser that we use would require 29 overlapping HIFU ablations. During those 29 ablations, what if the patient moves a little and the device misses a spot? When treating cancer, it’s important to get all of it. The vast majority of HIFU centers use ultrasound guidance (instead of MRI), losing the precision of MRI and the important real time information that MRI thermometry provides in protecting vital structures. As a result, studies show significant urinary and sexual problems after HIFU, less than surgery, but much more than our experience with laser.
Before choosing a center for your focal prostate cancer treatment, consider asking the physician:
1) Do you use a 3T MRI, an inferior 1.5T MRI, or no MRI during the procedure to guide the treatment and minimize collateral damage?
2) Do you use 1 plane or 2 plane temperature mapping when the laser fiber is on?
3) Have you completed an ACGME certified interventional radiology fellowship or completed a non-ACGME certified fellowship?
4) Do you use intravenous conscious sedation to minimize pain and anxiety during the procedure?
5) Do you use capnography as part of your patient monitoring to increase safety?