Oliver Sartor, MD, and Leonard G. Gomella, MD, discuss multiple topics involved with prostate-specific antigen (PSA) screening, including PSA velocity, guidelines, and cutoff age.
Oliver Sartor, MD
OncLive: It’s controversial, but you have both argued that prostate-specific antigen (PSA) screening is worthwhile. Please summarize the comments you made on this issue.
Sartor: It’s a really good question, and I’ll boil it down to a single statement: I get my PSA tested. Now, there are pros and cons to testing PSA. The downside is that if you use PSA as a measure, you’re going to be diagnosing a lot of cancers that don’t need to be treated. And the question is, “Do we have the wisdom to be able to separate those tumors that need to be treated from those tumors that don’t?”
We’re pretty good at identifying those tumors that absolutely need to be treated, but we’re not quite as good at identifying those tumors that don’t need to be treated. So, to me, the PSA question really revolves around whether we know how to treat these tumors wisely or not, and I believe that I’ve reached enough of a comfort zone so that I can make those decisions in a reasonable manner.
Gomella: Our challenge, I agree, is that we need to find the aggressive cancers while avoiding the overtreatment of the nonaggressive cancers. And this is where we’re running into a little bit of a controversy with the United States Preventive Services Task Force, which basically feels that no man should be screened for prostate cancer, regardless of risk factors.
Most of us feel fairly strongly that there are men who really need to be considered for screening, particularly if they have a very strong family history or certainly if they are African-American, a group that has among the worst prostate cancer mortality in the world. To say that no asymptomatic man should ever be screened for prostate cancer is to do a disservice to a large group of patients.
Leonard G. Gomella, MD
A lack of uniformity in guidelines for prostate cancer screening can complicate patient and physician decisions about when or whether to screen. Should a discussion of potential treatment options also enter into the decisionmaking process?
Gomella: There’s no question that you need to have an informed discussion with your patient concerning the risks and benefits of screening for prostate cancer. Based on changes in how we approach prostate cancer, that discussion should include the caution that many men who are diagnosed with cancer do not require active treatment, but can be offered active surveillance.
So, part of your discussion about screening involves telling the patient, “OK, Mr. Jones, if we do find prostate cancer, please understand that we may not recommend treatment. You may have the type of cancer that is very acceptable for what we call ‘active surveillance,’ and does not require an active treatment such as radical prostatectomy or radiation therapy.”
You have said that changes in PSA over time may be more relevant in diagnosing prostate cancer than the PSA number at initial screening. Can you describe how PSA velocity factors into the screening of patients for prostate cancer?
Gomella: We’re really starting to learn more and more about PSA, what works with PSA screening and what doesn’t work. And while the individual number can be important, particularly if it’s high, what is probably more important in that usual range of <10 is a change in the PSA over time.
The number that’s getting a lot of attention right now is something known as a PSA velocity of 0.4 mg/dL per year, and that appears to be the critical number. According to research done by William J. Catalona, MD, [at the Robert H. Lurie Comprehensive Cancer Center, Chicago, Illinois], patients whose PSA velocity goes up on more than one or two occasions by 0.4 are the ones who will most likely develop a cancer that requires biopsy and treatment. Conversely, patients with a relatively flat PSA velocity can probably be watched.
Sartor: Unfortunately, we don’t have data on PSA velocity, except for a little bit of surveillance data, which is controversial. I’ve talked to Peter T. Scardino, MD, at Memorial Sloan-Kettering Cancer Center about his work on this. In a recent study, his institution was unable to demonstrate that rising PSA velocity was a good indicator of the presence of prostate cancer.
What is the age at which a healthy man should stop being screened for prostate cancer?
Gomella: We try to discourage patients from screening once they get to their 10-year life expectancy, which, on paper, for the average American, is age 75. But we don’t stop them if they want to be screened.
Sartor: Johns Hopkins University School of Medicine published a dataset demonstrating that if somebody had a normal PSA at age 75, the probability of them dying from prostate cancer was incredibly remote. So, if you’re age 75 and you have a normal PSA, you probably are extremely low-risk.