Dr. Sean Collins: Prostate Cancer Treatment with CyberKnife - [Video Transcription]
- Who is the ideal prostate cancer patient for CyberKnife?
The ideal prostate cancer patient for CyberKnife is someone who has prostate cancer that is localized to their prostate and has not gone to their lymph nodes or their bones. There are two different classes of prostate cancer patients. There are patients who have low risk prostate cancer and patients who have high risk prostate cancer. The patients with low risk prostate cancer are those with low PSAs and low Gleason Scores. They are candidates for getting CyberKnife alone. The treatments are about five treatments over one to two weeks. The patients that have high risk prostate cancer are those with higher PSAs and higher Gleason Scores. We usually do conventional radiation for five to six weeks and then give a CyberKnife boost over one week. If you want specifics, a Gleason Score of seven and less or PSA of ten to twenty and less is a candidate for the monotherapy (five treatments alone). If your Gleason Score is higher than seven or your PSA is higher than ten to twenty, we usually do the combined treatment. The issue with CyberKnife is different from other radiation treatments. Some patients are treated with radioactive seeds. For radioactive seeds, you have to have a very specific sized prostate. CyberKnife does not limit by prostate size. You can have a very large prostate size and still get CyberKnife treatment. - How is CyberKnife different than conventional radiation therapy for prostate cancer?
There is one limitation of prostate cancer. Believe it or not, your prostate actually moves when your bladder fills and when your rectum fills. The way that the radiation oncologists have taken care of that in the past is that they have used large treatment margins or large radiation fields to treat prostate cancer. Unfortunately, your rectum and your bladder are right next to your prostate. So that limits the ability to escalate dose or increase doses of radiation to your prostate. If we are treating larger field sizes, we are treating more bladder and rectum. The CyberKnife is unique in that we can put gold fiducials into your prostate and the CyberKnife can actually track where the prostate is. If we know where the prostate is, we can actually follow it. Our machine actually dose follow the prostate as it is moving. We can then use smaller treatment margins. Also the CyberKnife treats from many different directions. The CyberKnife actually rotates around the body and treats from hundreds of different angles. It is much more precise than conventional radiation. So, it is smaller margins and high precision that allows us to give higher doses of radiation over a shorter period of time which is generally five treatments over one to two weeks. - What is involved in undergoing CyberKnife treatment?
The first that we do is put gold fiducials into your prostate so that the CyberKnife can actually track the prostate’s motion. It is usually done by a urologist as an outpatient procedure with minimal pain. The next step is that we wait about a week for the fiducials in the prostate to fix. Then, we get a CT scan and an MRI of the pelvis and prostate so that our computers can tell actually where the prostate is. We have a full time physics staff that does treatment planning. While the patient is at home enjoying themselves and spending time with their family, we are busy doing treatment planning. That takes about a week. The patients them come back usually for five treatments. They have to lay on a table for an hour. They get off the table and go home. They are done in one to two weeks. - How will I feel after the CyberKnife treatment?
The most common answer I get is "Did you turn the machine on?". Usually about a week or two after the treatments, you can have some bowel/bladder frequency which can last for about a week or two. It then goes away. It is pretty similar to the side effects that you get with conventional radiation, but instead of having it for two months you only have it for a few weeks. - Why should I come to Georgetown for my CyberKnife treatment?
Treating prostate cancer is a team sport. It depends on surgeons, radiation oncologists, and medical oncologists. When we treat patients with radiation, we have therapists who administer it. We have physics staff that help plan it. We have nurses who help the patients during the course of their treatments. Georgetown has had a CyberKnife for seven years. We are one of the busiest centers in the world. We are probably one of the most experienced centers in the world. I think that we give a great quality of care with limited sides and have great outcomes. - You collaborate with Dr. Lynch. Why does this benefit the patient?
Unfortunately in most situations, the urologist and radiation oncologist don’t work closely together. Here at Georgetown, Dr. Lynch and myself have developed a team where we analyze patients at the same time to tell them what we think is best for them. Sometimes surgery is the right answer for the patient. Sometimes radiation is the right answer, but it is important that we get together to see which patients fit the criteria. I would say that patients get the optimal treatment when they come to Georgetown because of that collaboration.