Health organizations' guidelines about PSA screening for prostate cancer can be confusing. Dr. Ross Krasnow discusses how he advises men about the test.
TRANSCRIPT
Introduction: MedStar Washington Hospital Center presents Medical Intel, where our healthcare team shares health and wellness insights, and gives you the inside story on advances in medicine.
Host: Welcome, everybody, and thanks for joining us today. We're talking to Dr. Ross Krasnow. He is a urologic oncologist at MedStar Washington Hospital Center. Welcome, Dr. Krasnow.
Dr. Krasnow: Thank you for having me.
Host: So, we're going to talk about PSA testing for prostate cancer. In 2016, Ben Stiller, the actor, made waves with a blog post titled, "The Prostate Cancer Test That Saved My Life," in which he encouraged men to learn more about PSA testing, and it was something that he had gone through personally. And, the article also renewed a debate between medical professionals and organizations about the effectiveness of this test. Please explain to us a little bit more about what PSA testing is. Why is there so much debate surrounding this test?
Dr. Krasnow: PSA stands for prostate specific antigen. It is a substance that the prostate actually secretes into the ejaculate. The prostate is a sexual organ. It's not really supposed to be in the bloodstream, but it does leak into the bloodstream in small amounts. When a patient has prostate cancer, PSA will be secreted into the bloodstream at a higher level. Because of how PSA can be elevated in the bloodstream, it can be used as a screening test for prostate cancer, and it has been used successfully as a screening test for prostate cancer. Unfortunately, some of the data that demonstrates the efficacy, or lack thereof, of PSA testing for prostate cancer, is controversial. Specifically, in 2012 the US Preventative Task Force gave PSA testing a grade D recommendation. What that means is that they thought that the benefits of testing did not outweigh the harm, and they did not recommend PSA testing in men. In May of 2017, the US PTF, the US Preventative Task Force, revised their recommendation, and upgraded the recommendation to a grade C recommendation in men between the ages of 55 and 69.
What this grade C recommendation means is that the test should be offered based on the professional judgment of the clinician and patient preference. Prostate cancer screening works when used properly, but there are harms. That's why the Preventative Task Force came out with their recommendation in 2012. And those harms are a false positive rate of 15 percent. That means that 15 percent of men with an elevated PSA may not have prostate cancer at all and undergo unnecessary testing. When I say unnecessary testing, that primarily means a prostate biopsy, and a prostate biopsy can have complications. Also, there is a real risk of overtreatment. Most of the prostate cancer that's diagnosed with the prostate biopsy ends up being low-grade prostate cancer, also what we call indolent prostate cancer. Yes, under the microscope, the cells are abnormal, and it's technically called prostate cancer, but it's unlikely to negatively impact that man's life in any way. Also, there's a risk of over-detection of prostate cancer in men who are older with a lower life expectancy. Prostate cancer is a very slow-growing cancer, and it takes 10 to 15 years for it to progress, and maybe even longer for it to cause death. So there's not a lot of utility in screening and treating older gentlemen.
Host: So, what do current screening guidelines say about PSA tests then? So, for example, like the US Preventative Services Task Force or American Cancer Society?
Dr. Krasnow: As I mentioned, the updated recommendations from the US Preventative Task Force give it a grade C recommendation for men between the ages of 55 and 69. This means that a conversation needs to take place between the physician or advanced practice provider ordering the PSA test and the patient to understand the risks and benefits associated with PSA screening. And really, the American Cancer Society and American Urological Association guidelines have a similar emphasis on shared decision-making. The American Cancer Society updated their recommendations in 2016. They recommended that screening should start at the age of 50 after a conversation using shared decision-making takes place. They also recommend screening, specifically African-American men, starting at the age of 45, and they recommend screening patients with a family history of prostate cancer at the age of 40. The American Urologic Association has similar recommendations. They recommend starting screening a little bit later at the age of 55, but again they emphasize the importance of the patient understanding the benefits and harms of screening before undergoing PSA testing. The American Association of Family Physicians hasn't revised their recommendations in some time, but they do not recommend screening at this time.
Host: As a younger male, how is a man supposed to know which guidelines to follow?
Dr. Krasnow: There really is no right or wrong guideline to follow. The key is that the patient themselves has to engage in the decision-making process with their provider to decide whether they should undergo PSA testing or not. They need to understand the benefits of PSA testing, that PSA testing can lead to a decrease in the risk of a prostate cancer mortality, but they also need to understand that you have to screen a lot of patients before you save even one person, and the treatment for prostate cancer has its own risks associated with it. One person may feel that they don't want to undergo that type of test for what they find to be minimal benefit. Another person may say, "You know what? I want to know if I have cancer, and if I have it, I want to treat it, because I don't want to face the long-term consequences of having a cancer down the line." The other thing to mention is that the detection of prostate cancer with PSA testing may not impact survival as much as we would expect, but there is a lot of benefit to preventing patients from having progressive prostate cancer that either invades into local structures or becomes metastatic. I've certainly seen patients in my practice who have advanced prostate cancer that spreads to other organs and they feel that, had they had testing at an earlier stage, an intervention could have been offered sooner.
Host: That makes me wonder, you know, have you seen patients like Ben Stiller, who is a younger male than I guess what is presented in those guidelines to follow, in which this test found the cancer really at the really early stage of their lives, or have you seen patients who went through a biopsy and it turned out that the test was false positive?
Dr. Krasnow: I've definitely seen both of these types of scenarios. I have a specific patient in mind that I treated. He was a very young gentleman. He was less than 50 years old, who ended up getting a PSA test because he had some urinary symptoms. In reality, based on the strict screening guidelines, he may not have needed a PSA test at all because he was less than 50, but it was warranted because he had some urinary symptoms. His PSA was very, very high. At that point, we did a prostate biopsy on him and it showed only a very small focus of low-risk cancer, but something didn't make sense. His PSA should not have been that high for having such a low, small focus of cancer on the biopsy. So we had a long discussion about what the next step should be. Should we continue PSA testing? Should we treat? Should we do an MRI? We ended up doing an MRI, which showed an area that was of concern for a higher-risk cancer. We then discussed the potential treatment options, and he elected to undergo a radical prostatectomy using the robotic platform. And at the end of the day, his final pathology was a very high-grade cancer that left unchecked would likely have led to a lethal prostate cancer, so I was very relieved that he had had that PSA test and that we had intervened. On the other side of the spectrum, I'm often referred patients in their 70s, mid-70s or patients who have a lot of medical, what we call comorbidities. That means they have a lot of other medical problems—heart problems, lung problems, vascular problems, and they end up being referred to me for elevated PSA and for a biopsy. And when I meet with them, I say, "You know what? We should not biopsy you because we're likely to find prostate cancer or likely to find an indolent prostate cancer, but it's unlikely to ever affect you in your lifetime. So, I feel that I have avoided overtreatment in many patients as well. I think the key is to be smarter about testing, being more selective.
Host: How do you advise men regarding prostate cancer screening and do you find the test valuable, or do you think more men are harmed than helped because of false positives?
Dr. Krasnow: Let's not forget that prostate cancer is by far the most common cancer in men. Over 160,000 men are diagnosed with prostate cancer each year, and it's the number 2 cause of cancer death in men with 26,000 men dying of prostate cancer each year. This number is really comparable to breast cancer in women. Since the inception of PSA testing, there has been a sharp decrease in prostate cancer mortality. Approximately 1 out of 7 men in the US will be diagnosed with prostate cancer during their lifetime, and nearly 2.8 percent of men will die from the disease. We've discussed how PSA testing can decrease prostate cancer mortality and that treatment is associated with better survival over just watching it, so yes, I think that we definitely can help patients through PSA testing, but we can cause harm if we test the wrong patients. So, we really need to engage in smarter PSA screening.
I think an important key is the shared decision-making so that patients really understand the benefits and risks associated with testing. I think we need to be smarter about screening patients who are at an increased risk of prostate cancer, such as African-American and those who have had a close family member with prostate cancer. I think that it's reasonable to start screening even at an earlier age, such as 50 or below, and I think that there is now data that suggests that a low PSA at the age of 50 may suggest that you don't need any further testing, and so I think that is something that's coming down the line. It's important that we don't test patients who have a life expectancy of less than 10 years because they're really unlikely to derive any benefit from the testing and any further workup or treatment could definitely result in harm. I really advocate for stopping screening at the age of 70, except in only rare situations where someone is extremely healthy for their age, has a long life expectancy and, for whatever reason, is extremely burdened about the health of their prostate. I think it's important that we check PSA in men with urinary symptoms, especially before procedures or treatment of benign prostatic hyperplasia, like the young gentleman I told you about earlier.
Host: Dr. Krasnow, are there certain men who are at risk for prostate cancer and should be screened earlier or more frequently?
Dr. Krasnow: Absolutely. There are populations of men who are at increased risk of prostate cancer. Race is strongly correlated with prostate cancer mortality. African-Americans have at least double the incidence of prostate cancer compared to white men. And it's not only that the incidence is higher. They have an increased risk of high-risk prostate cancer and they have a 2 to 3 times increased risk of dying from prostate cancer, so not only is this a population that's underrepresented in the medical literature, but they're at increased risk of having an adverse outcome from prostate cancer, so it's more important that we screen in that population. Another important population that I talked about earlier is men with a family history of prostate cancer, and when I say family history I specifically mean those who have a father or a brother with prostate cancer. They have a much higher risk of developing prostate cancer, and again, more importantly, a higher risk of dying from prostate cancer. And studies suggest that screening in those patients with a family history may decrease prostate cancer death by 50 percent. We are also developing a better understanding of those who may have an increased genetic predisposition to prostate cancer. For example, one of the most common causes of breast cancer is a gene mutation called the BRCA gene, associated with breast and ovarian cancer in women. And what we're learning now is that men who have this mutation also have an increased risk of prostate cancer and an increase in lethal prostate cancer. Now we know that men who have a family history of breast cancer in the women in their family should also be more aggressively screened for prostate cancer.
Host: So, to me it sounds like the PSA test and the screening, it's effective. What's the future for prostate cancer screening? Are there better methods coming down the pipe?
Dr. Krasnow: I definitely think that PSA testing is effective when used in a smart fashion in patients who are younger and in patients who are more likely to die from prostate cancer. But the test could definitely be improved. Also, we're understanding that just because a man has a diagnosis of prostate cancer doesn't mean that we have to treat them for prostate cancer. We can effectively prevent prostate cancer death by watching the cancer closely. But, there are better methods coming down the pipeline. There's a lot of interest in earlier screening for prostate cancer, but not yearly screening. There was recently a publication by my colleague, Mark Preston, in the Journal of Clinical Oncology that showed that by essentially screening with a single PSA test at a younger age, if your PSA value is below a certain cutoff, you may never need PSA screening again for the rest of your life, and I think that's a very exciting proposition to say, OK, at the age of 45 we are going to do one PSA test. If it looks OK, we never have to do it again. That would certainly prevent screening in a large amount of patients, but we're not there yet. Also, we're better integrating advanced imaging into the diagnosis of prostate cancer. Specifically, I mean MRI for prostate cancer—magnetic resonance imaging. This type of imaging has increasingly been used in men who had an elevated PSA and have had a negative biopsy, but a scary high-level PSA, and it can be used to see prostate cancer that you can't see on the ultrasound and detect by routine biopsy. Now there is data that suggests that we may be able to push the MRI into an earlier phase and use it in the screening process, so instead of the process being an elevated PSA leading to a negative biopsy, leading to an MRI, leading to another biopsy, maybe a smarter way to do it is an elevated PSA, leads to an MRI, and then if there is something suspicious on the MRI, then we do the biopsy. This is new because up until recently the MRIs haven't had a high enough resolution to really see prostate cancer. There's also better biomarkers for prostate cancer. One is called the 4K score. It uses not just PSA, but PSA that's found in the blood and PSA that's further broken down by the body, and it may also be useful in screening patients who have an elevated PSA prior to biopsy to better detect those who may just have a lethal prostate cancer. And, in fact, MRI and these new biomarkers, like the 4K score, have recently been integrated into the NCCN guidelines. So, we've made a lot of progress in how to intelligently use PSA testing for the screening of prostate cancer. I think that we have more work to do, but it's looking even more promising, and I'm hopeful that we can further reduce the burden of screening and the harms of screening through these new technologies.
Host: That is really great news. I especially liked the part where you were telling us about how we can do it just one time at the age of 45 or so, and then never have to do it again. Hopefully, that time will come soon.
Dr. Krasnow: I hope so. It's early data now, but it's looking like that may be promising.
Host: Thank you very much for joining us today.
Dr. Krasnow: It was my pleasure.
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