Dana-Farber Expert: The 'Wrong Message' About Prostate Screening
Dr. Philip Kantoff, a leading expert on prostate cancer, is not usually the outspoken public critic type. But this time is different.
The director of Dana-Farber's Lank Center for Genitourinary Oncology, he is very publicly decrying a federal task force’s recent recommendation against routine prostate screening for healthy men. On the Dana-Farber Cancer Institute’s homepage, he puts it clearly: The panel’s report “is the wrong message.”
So what’s the right message? I asked to speak to him with a particular question in mind: Is “watchful waiting” — officially known as “active surveillance” — the central problem? That is, is the PSA screening test drawing federal fire and causing men to be over-treated for prostate cancer largely because it’s just so hard to be told you have cancer and not do something very interventionist about it? Would PSA screening be more acceptable to medical authorities if we stopped over-reacting to the results?
[module align="right" width="half" type="pull-quote"]'The PSA created a bunch of problems but it is a clear advance.'[/module]
But the issue is too complex to distill it down to one question. Here’s our conversation, lightly condensed. My takeaway from Dr. Kantoff’s explanations:
Turning thumbs down altogether on the PSA test would set prostate cancer treatment back 25 years. Instead, we need to refine how the test is used. Men with short life expectancies should not be screened at all; some men with elevated PSA levels should not get biopsies. And most of all, more men should opt for restrained ‘active surveillance,’ hard as it may be.
Q: On the Dana-Farber Web page, you say the latest recommendations on prostate screening are the wrong message. What’s the right message?
Let’s begin with a 3-minute overview:
The PSA [Prostate-Specific Antigen] test was developed around 20-plus years ago, and has been used widely in The United States, and it has allowed us to make the diagnosis probably 10 years earlier than before.
It therefore did two things: It pushed back the date of diagnosis — and the stage at the time of diagnosis — so that very few people presented with metastatic disease when they came in the door, as was the case prior to the advent of the PSA.
But at the same time it uncovered a lot of cancers that did not need to be diagnosed, that were non-lethal cancers. However, for quite a number of years in the United States, people treated everything that came their way.
So the problems with PSA screening are:
First of all, there are people with an elevated PSA that don’t have prostate cancer and undergo an unnecessary biopsy. It happens, and there’s a certain amount of cost and morbidity associated with having a biopsy.
Number 2: There are people who have an elevated PSA who probably never should have been screened for it because their life expectancy is short [and prostate cancer is often very slow-growing.] i’m not going to give you a specific age here, but screening older men is not a very cost-efficient or risk-efficient way of doing things. But it has been going on, untethered. For example, more than half of men over the age of 80 are getting PSA-tested.
And finally, there are many people who get diagnosed and get treated unnecessarily, and develop side effects of treatment unnecessarily as a result of it.
The latest findings
Then the randomized prospective large trials came out in the last two years, and the message to me is pretty clear. And that is, PSA screening reduced mortality from prostate cancer. That’s my interpretation of the data.
Number 2: The mortality from prostate cancer in the first 10 years after screening is very low, so what you’re doing, presumably, is reducing mortality minimally in the first 10 years and presumably more in the 10 years that follow.
And number 3, the number of men needed to treat in order to save a life is quite high, and that’s a result of the over-treatment issue.
Dissecting the problem
The panel has gotten the message wrong. What I think is the issue is that you need to dissect this problem into its component parts. And that is:
Number 1, that using PSA detects cancer earlier and saves lives.
Number 2, there are many men who don’t need to get screened and are getting screened, and we need to control that. We need to rein that in.
Number 3, there are many men with elevated PSAs who don’t need to get a biopsy for a variety of reasons. And we need to understand that more, and understand who with an elevated PSA does not need a biopsy. That issue needs to be studied much better.
And finally, and most importantly, we need to use active surveillance much more proactively. Many of us have been big advocates of it for a number of years, and it’s really taken off mostly in some of the academic centers — a little bit less in the community, I suspect. But if you look at patterns of care, active surveillance has not taken off as it should have taken off in the last few years, and we need to advocate for that.
Throwing away the PSA is the wrong answer. That, to me, is like saying we’re going back to 25 years ago, when everyone who came in the door had metastatic cancer and died of prostate cancer, and the mortality rate was higher. It declined about 25%, presumably because of a combination of early detection and improved treatment.
It’s hard to know how much of that decrease in mortality has been the result of screening and how much of better treatment — but to go back to 25 years ago?? What we should be thinking about is how to improve on where we are right now, and refine the decisions on who needs to be treated.
‘You need to relax’
Q: You emphasize active surveillance, but what I’m imagining is that it’s just incredibly hard to do nothing when you’ve been told you have prostate cancer. Isn’t the natural reaction something like, “Get this thing out of me?”
Maybe I have a self-selected population of men who see me, but if you tell people, ‘Your prostate cancer should not be viewed as a life-threatening cancer. Your prostate cancer is a different disease, and frequently it doesn’t need to be treated. You need to relax, and you likely don’t need to be treated,’ most men will accept that.
I’m not saying that active surveillance is for everybody, I’m saying there’s a significant proportion of men who don’t need to be treated. Somewhere between 25 and 50% of men right now do not need to be treated. The key to me is: one, the subset of men who have a limited life expectancy, and two, many men with low-grade cancers.
About 40 to 50% of men, when they have a biopsy, all they have is a low-grade cancer. I can say with fairly high assurance that if you have a low-grade cancer, it’s unlikely that it’s going to progress to the point that you die of prostate cancer.
The problem we have is that the sampling of the prostate is imperfect. What people have to buy into is getting repeat biopsies. That’s the only way at the present time to accurately follow people. In that context, PSA is not very reliable, nor is feeling the gland. So you need repeat biopsies every year or two.
If the repeat biopsy shows something more aggressive than was originally found, then you ‘fall off’ active surveillance and get treated. But you know better that you do need to be treated.
We need to embrace that more and understand that more. That’s a big piece of this problem, and the task force’s recommendations sort of jumbled everything together into one gemish and said, ‘Let’s go back to 25 years ago.’ The PSA created a bunch of problems but it is a clear advance.
A New York Times Q&A about PSA screening in light of the panel's recommendations is here, and a fascinating NY Times magazine story about the whole PSA controversy is here.
An internist writes in USA Today about his decision to keep using the PSA test here.
This program aired on October 13, 2011. The audio for this program is not available.