How to choose the best prostate cancer treatment to preserve sexual function? What is Focal Therapy, or Tissue Preserving Therapy in prostate cancer? Risk vs. benefit in prostate cancer therapy. Dr. Anton Titov, MD. You have already discussed that. Preservation of sexual function, urinary bladder function, and rectal function is a very important issue to consider for patients undergoing prostate cancer treatment. How do you choose the treatments with the goal of maximizing curative potential and the results of the treatment? But also to make sure that sexual and urinary functions are preserved after prostate cancer therapy. Dr. Mark Emberton, MD. Yes, this is very good question and this is the challenge. It's the great satisfaction we get as clinicians. We try and help patients negotiate this very complex prostate cancer decision making. And prostate cancer does present a challenge. There are prostate cancer trials being published that compare surgery with doing nothing. There's no real difference in survival. The PIVOT prostate cancer trial is an obvious example. It's been criticized for lots of reasons, and the result may not be true. But nevertheless it is the result that we have. And if there is a difference between intervention and non-intervention, it's not going to be a huge difference. One is going to need many thousands of prostate cancer patients over a decade to show a difference. So we talk about therapeutic ratio in medicine. It is the probability of doing benefit and the probability of doing harm. Dr. Anton Titov, MD. Therapeutic ratio for prostate cancer is low. So it's possible to harm many prostate cancer patients. But not many patients benefit. And that's a tough decision. And so that's what has led us to try and come up with a different approach to prostate cancer care. Dr. Mark Emberton, MD. And we've been able to do that because of the advent of MRI. MRI helps to make a better risk stratification that we've spoken about earlier on in this conversation. We moved away from treating the prostate to treating the cancer within prostate. We can preserve the architecture of the prostate. Therefore we can diminish the harms that are incurred by the nerves, by the blood supply, by the rectum, by the anal sphincter and by the bladder. All of them are key structures in driving genitourinary functions, sexual function and also urinary function. And that approach we've called Focal Therapy, or Tissue Preserving Therapy, Tissue-selective Therapy. And that prostate cancer therapy has been the subject of work that we've been doing now for 6 or 7 years. And taking men through trials to prove that Tissue Preserving Therapy is safe. We have to prove that we can eradicate the prostate cancer. We have to prove we can do so without affecting these critical functions. And I think the answer to our work so far as that yes, we can do it. We can eradicate cancer in about 90% of these prostate cancer patients. Some patients will need a 2nd treatment. And some prostate cancer patients will need to go on to surgery and radiotherapy. But the majority will be ok, and we can do so as a day case prostate cancer therapy procedure. It takes just one day, without affecting continence and keeping most men with good sexual function. And I mean 90 to 95% of them after the treatment. This is a major change from what was done in prostate cancer before. Dr. Anton Titov, MD. So focal therapy can improve therapeutic ratio of prostate cancer treatment to a much better balance of benefit vs. risk of side effects. Yes, so the prostate cancer therapy side is an assumption, because we just don't have long-term follow-up yet. And ultimately it's about living longer and not dying of prostate cancer. Dr. Mark Emberton, MD. We haven't been doing this for 10 to 15 years, which is what you need. But there's no question that we've changed the side effect profile of prostate cancer therapy dramatically. And I can look someone in the eye, when I'm talking about focal prostate cancer therapy, and I can say, "You will not be incontinent". I can look them in the eye and say, "There's a 90% to 95% chance they will keep erectile function”.