Prostate Cancer: Radiation Therapy for Local Recurrence

A question I often get is, you know, why did my cancer come back if it's been treated before, right? And here are some basic risk factors I usually discuss with patients that we've known about for quite some time.

So, for example, you heard, if you were here this morning with Dr. Cornelia Ding's talk on pathology and how aggressive we call this the grade, and so I have a picture here of You know, something that we call Gleason 3, where the cells are a little more uniform, to something that's called Gleason 5, and these cells are very aggressive.

Well, we just know these tend to be a little more treatment-resistant and prone to coming back, either in the radiation area or in the surgical zone.

The next two pictures I have there are of MRIs, similar to what Dr. Baer showed earlier about prostate cancer and the utility of MRIs.

You know, when prostate cancers like to kind of extend beyond their capsule, right, this kind of means that they're a little more aggressive.

Now, to be clear, that doesn't mean it's metastasized.

This is a local phenomenon, right? But often what we see at the time of surgery, there might be a little extra capsular extension that wasn't even seen on the MRI.

In this figure, it's pretty obvious.

I kind of outlined the prostate there in red.

And the arrow is where I kind of point the prostate cancer bulging a little bit on that left side in that kind of dark figure, right? The figure next to it is about seminal vesicle involvement.

And some people ask me, like, what is a seminal vesicle? Well, just as a very quick recap, if your prostate's like a head, I always say the seminal vesicles are sort of the bunny ears that lie on top of it, right? And so prostate cancer loves to head in that particular direction upwards.

And we also know that even with radiation or surgery, this is a risk factor for cancer coming back in that target zone.

The last, I guess, risk factor is more surgically oriented.

And some people ask me, what is a positive margin? How did this happen? And the surgeon goes in and tries to remove your prostate.

As Dr. Carroll says, with improved fluorophores, this might change.

But sometimes, without recognizing, there could be a little bit of that cancer left behind.

So in figure A, we have, for example, a tumor coming out with normal tissue around it, where a pathologist will say, oh, look at this slide.

There's tumor, and then surrounded by tissue.

That's what we would hope for.

And figure B there on the kind of the bottom of that figure, unfortunately, they kind of cut through the cancer.

And on the other side of that specimen, you would assume there's a little bit of cancer left.

Now, I always tell people that just because you have a positive margin doesn't necessarily mean that something might come back.

Not all positive margins are made the same.

There's size and grade that you have to think in the clinical context.

I think a lot of this got discussed, but I'll just kind of go through my evaluation of how we look at local recurrences.