Prostate cancer treatment methods. Surveillance, radical prostatectomy, or radiotherapy? 6
Prostate cancer treatment guidelines are behind precision medicine advances. Best treatment for prostate cancer in early stages may be observation. Choose prostate cancer therapy wisely. Dr. Mark Emberton, MD. Let’s go back to localized prostate cancer, back into the prostate. The first treatment decision that we make when discussing with the patient, is whether to treat or not to treat. Whether to keep the cancer under surveillance. Because we don’t feel that, if left alone, the prostate cancer is likely to progress. We sometimes feel that prostate cancer will not cause a detriment to quality of life or limit life expectancy. And that is done with PSA and increasingly with prostate multiparametric MRI. We have talked about it. Prostate MRI is particularly useful because it is reliable. We can watch the prostate over time. We are going to hear a lot more about how good MRI is at detecting prostate change when change in prostate cancer occurs. And surveillance is an interesting form of prostate cancer care. Surveillance is to identify men with prostate cancer who progress. Those men who have prostate cancer progress then get treatment. So it’s Delayed Selective Intervention. You avoid treating those men who don’t need prostate cancer treatment. And what we do know now is that over 10 to 15 year timeframe active surveillance is very very safe. Dr. Anton Titov, MD. We are talking about years of progression between the subsequent prostate MRI scans. It’s not weeks, months, but it’s years? Most prostate cancer stays stable. The challenge is to identify those prostate cancers that progress. Now, with MRI we are going to enter a new era. Before multiparametric MRI was available, we were using transrectal guided prostate biopsy. We’ve already discussed that was an imprecise way of assessment of prostate cancer. When you repeat prostate biopsy, it’s also imprecise. Dr. Anton Titov, MD. Because you could be sampling different areas of prostate tumor or healthy tissue. Dr. Mark Emberton, MD. Correct! And so we never really knew whether the tumor has progressed, or whether we were just sampling a new part of the disease. Dr. Anton Titov, MD. This is not comparing apples to apples, but apples to oranges. Dr. Mark Emberton, MD. Correct! It was the reclassification vs. progression dilemma. Prostate MRI is reliable. If I do an MRI three times today, it will come up with the same result. We can actually watch a prostate cancer lesion over time. We have learned, we’ve been doing MRIs here for a long time, that most prostate cancer lesions remain very stable. Now, clearly, cancers grow. But prostate cancers have little spurts of growth and then achieve stability. Maybe prostate cancers undergo a genetic mutation and then grow some more. So we have seen prostate cancer progressors. But they are rare. And when we do see progressive prostate cancer, we obviously treat them or biopsy them immediately. Dr. Anton Titov, MD. And before you see any cancer growth progress on MRI, you might not even do biopsy? Dr. Mark Emberton, MD. Correct. So just keep surveilling. If you see the progress on MRI, tumor growth, you biopsy the tumor. You proceed with local prostate cancer treatment or with a whole-gland cancer treatment. That’s exactly right. So that’s the most conservative approach that we have. That’s called Active Surveillance. In terms of localized prostate cancer, the most aggressive approach is the opposite. It’s removing the whole prostate or irradiating the whole prostate. There are various ways to do both of those. Prostate removal can be done through an open operation, or laparoscopic operation. It can be done with the assistance of a robot. Radiotherapy can be given with various types of administration. People will have heard of conformal radiotherapy. We try and shape the radiation beam. We have prostate cancer image-guided radiotherapy. We put some markers inside the prostate and we can watch the prostate move with time, and the beam follows those markers. Dr. Anton Titov, MD. Those markers are called fiducial markers. We can put the radiation source inside the prostate with iodine-seed brachytherapy, or high-dose rate brachytherapy. Proton beam therapy for prostate cancer. The UK has just invested in proton beam therapy. It is very expensive. Protons are particles that are used for radiation. Proton beam therapy typically was used in children. It was used for therapy of cancer in the back of the skull, and in head and neck. Proton beam therapy is also used in sarcoma, because of their ability to penetrate and deliver the energy in a precise point in space. But, obviously, in the prostate, there maybe some utility for proton beam therapy, given the proximity of the rectum and the bladder. But these are research questions going forward. So there’s lots of different types of radiation prostate cancer therapy. Dr. Mark Emberton, MD. Currently, all of them, except in a very very few centers, aim at the whole prostate. And surgery is aimed at the whole prostate, I think in nearly all centers. I can think of one medical center , which aims to treat the whole prostate. There’s one surgeon in the north of France who is removing surgically prostate cancer that is accessible to the surgeon. He does it by cutting out like a slice of cake from the prostate, if that slice contains the tumor. Dr. Anton Titov, MD. Sounds like a lumpectomy? Dr. Mark Emberton, MD. Correct. Exactly right. But just a few of those prostate cancer cases have been done to date. In prostate cancer radiotherapy, there are a few groups around the world who are now using the modern techniques to try and focus down the beam onto the tumor, and to try and preserve the prostate. If you do that, you can give additional dose to the tumor, which makes prostate cancer radiotherapy more effective. It also reduces the radiation dose to the bladder and rectum.
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