Abandoning PSA Screening Could Cost Lives: Study

[Steve Williams]

By Steven Reinberg



MONDAY, July 30 (HealthDay News) -- In the wake of a widely publicized report advising against prostate-specific antigen (PSA) testing for prostate cancer, a new study finds not screening would triple the number of U.S. men developing advanced cancer.
Testing, on the other hand, might keep some 17,000 men each year from receiving a diagnosis of late-stage prostate cancer -- cancer that has spread and is far less curable -- the study finds.
"PSA testing, for all its pluses and minuses and all that . . . permits you to catch the disease earlier," said lead researcher Dr. Edward Messing, chair of urology at the University of Rochester Medical Center in Rochester, N.Y.
"These people are all going to die, they are going to die incredibly expensively and die miserably," he said, referring to the many men whose diagnoses would be delayed by not testing. "I don't know that all these people could be saved with PSA testing," but many could, he added.
The report was published online July 30 in the journal Cancer.
Messing said the annual number of prostate cancer deaths dropped from about 42,000 in the 1990s to 28,000 now. "The only thing that can explain that is PSA early detection and treatment," he said.
Many cases of prostate cancer are not life-threatening, which is why testing is controversial. The U.S. Preventive Services Task Force (USPSTF) in May recommended against routine PSA screening, saying too many non-lethal cancers were being treated aggressively, exposing men who didn't need treatment to serious side effects such as impotence and urinary incontinence.
But Messing disagreed with that advice. Condemning PSA testing "wasn't a brilliant conclusion," he said.
For the new study, Messing's team compared information from the U.S. Surveillance, Epidemiology, and End Results database for the years 1983 to 1985 -- immediately before widespread PSA testing started --- to data from 2006 through 2008.
In the 2008 data, 8,000 cases of prostate cancer were diagnosed after the malignancy had spread to other parts of the body.
Using these cases as a base, the researchers constructed a model that used data of advanced cancer diagnosed in the 1980s and predicted how many cases of advanced cancer would have been diagnosed in 2008 if PSA testing was not done.
Their model showed instead of 8,000 actual cases in 2008, about 25,000 cases would have been diagnosed.
But the USPSTF maintains the benefits of testing are overrated. "The task force recommends against prostate cancer screening using the PSA test, as the potential benefit does not outweigh the harms," said Dr. Michael LeFevre, co-vice chair of the task force and professor in the department of family and community medicine at the University of Missouri School of Medicine.
As a result of treatments for PSA-detected prostate cancer, one out of 1,000 men screened in the United States develops a blood clot in his legs or lungs, two will have a heart attack or stroke, and up to 40 are left impotent or with urinary incontinence, LeFevre said.
"At best, only one of these 1,000 men who were screened avoids dying from prostate cancer for at least 10 years," LeFevre said. "In addition, about one in every 3,000 men screened dies as a result of surgery to treat cancer detected by the PSA test."
Still, the task force recognizes that "some men may continue requesting the PSA test and some physicians may continue offering it," LeFevre said.
Before getting this blood test -- which measures a protein in cells of the prostate gland -- men should learn about the pros and cons, he said. "The decision to start or continue screening should reflect an understanding of the possible benefits and known harms, and should respect each individual's preferences."
Messing advises men with a family history of prostate cancer or urinary symptoms to have a PSA test. Men with no family history or symptoms should discuss PSA testing with their doctor, he added.
Messing pointed out that screening-detected cancer doesn't mean surgery, chemotherapy or radiation treatment must follow. Most cases can be watched for some time, he said.
Dr. Otis Brawley, chief medical officer for the American Cancer Society, said over the past few years a number of studies have been published on the benefits and harms of PSA testing.
"None of these studies can be considered decisive other than in proving that there are some harms associated with treatment," he said. The American Cancer Society still supports screening for certain men in consultation with a physician.
Prostate cancer is the second-leading cause of cancer death among men in the United States. In 2012, more than 240,000 new cases are expected to be diagnosed, and 28,000 men will die from the disease, researchers say.

 

[Phelonious Ponk]

Screw the science, basic logic is missing here:

The U.S. Preventive Services Task Force (USPSTF) in May recommended against routine PSA screening, saying too many non-lethal cancers were being treated aggressively, exposing men who didn't need treatment to serious side effects such as impotence and urinary incontinence.

The side effects mentioned above are a result of over-aggressive treatment, not a result of knowing there was a problem in the first place. This is "I might overfill when I add oil to my engine, so I won't check the dipstick." And i apologize for the use of the word "dipstick" in a thread about prostate cancer.

Who is The U.S. Preventive Services Task Force? Is the insurance industry involved?

Tim

 

[ack]

In a discussion I had with my doctor recently, it doesn't look like many took that original study in May seriously, simply because you shouldn't stop screening for any cancer you can detect and treat. Just fix the treatment.

 

[Steve Williams]

In a discussion I had with my doctor recently, it doesn't look like many took that original study in May seriously, simply because you shouldn't stop screening for any cancer you can detect and treat. Just fix the treatment.

Right on Peter

I have a PSA done every year around my birthday

 

[jazdoc]

In a discussion I had with my doctor recently, it doesn't look like many took that original study in May seriously, simply because you shouldn't stop screening for any cancer you can detect and treat. Just fix the treatment.

But for prostate cancer there is a conundrum: most of the prostate cancers you can detect and treat will remain occult (asymptomatic) or indolent and never have a practical consequence. The incidence of occult prostate carcinoma steadily rises with age: "occult cancer of the prostate is present in men as young as 30 years and its prevalence is above 30% in men older than 50 years and 60% to 70% in men older than 80 years". Unfortunately, even after biopsy, we don't have very accurate predictors for which cancers are clinically significant and require treatment.

For a screening test to be effective, it must be highly sensitive (true positives), highly specific (true negatives) and your must screen a population at high risk. Unfortunately, PSA is neither. A recent study of nearly 3,000 men using the standard PSA cut-off of 4 ng/mL demonstrated low sensitivity, "with this cut-off only 20.5% of the prostate cancer cases test positive-nearly 80% of prostate cancer cases are missed. The specificity at this cut-off is high (93.6%) meaning only 6.2% of men who do not have prostate cancer falsely test positive."

The financial, physical and emotional costs of over-treating a biologically indolent cancer are just as real as the costs of missing the opportunity to treat an early stage cancer (i.e. assuming the treatment increases longevity). Simply discovering a cancer earlier doesn't necessarily mean that you are improving long-term prognosis (i.e 'lead-time bias'). Unfortunately, much of our literature for cancer screening is at best incomplete because population based studies are necessarily expensive and difficult. The effects of emotional/political overlays can't be denied. Just look at the calls for increased spending and screening when a celebrity gets behind a disease cause. While individual stories about screening are heart-rendering, since screening is a population based procedures, we need to examine population based outcomes to judge results.

Don't mean to sound harsh, but as a physician, I am acutely aware of the limited resources available. We need to use them wisely.

 

[Phelonious Ponk]

But for prostate cancer there is a conundrum: most of the prostate cancers you can detect and treat will remain occult (asymptomatic) or indolent and never have a practical consequence. The incidence of occult prostate carcinoma steadily rises with age: "occult cancer of the prostate is present in men as young as 30 years and its prevalence is above 30% in men older than 50 years and 60% to 70% in men older than 80 years". Unfortunately, even after biopsy, we don't have very accurate predictors for which cancers are clinically significant and require treatment.

For a screening test to be effective, it must be highly sensitive (true positives), highly specific (true negatives) and your must screen a population at high risk. Unfortunately, PSA is neither. A recent study of nearly 3,000 men using the standard PSA cut-off of 4 ng/mL demonstrated low sensitivity, "with this cut-off only 20.5% of the prostate cancer cases test positive-nearly 80% of prostate cancer cases are missed. The specificity at this cut-off is high (93.6%) meaning only 6.2% of men who do not have prostate cancer falsely test positive."

The financial, physical and emotional costs of over-treating a biologically indolent cancer are just as real as the costs of missing the opportunity to treat an early stage cancer (i.e. assuming the treatment increases longevity). Simply discovering a cancer earlier doesn't necessarily mean that you are improving long-term prognosis (i.e 'lead-time bias'). Unfortunately, much of our literature for cancer screening is at best incomplete because population based studies are necessarily expensive and difficult. The effects of emotional/political overlays can't be denied. Just look at the calls for increased spending and screening when a celebrity gets behind a disease cause. While individual stories about screening are heart-rendering, since screening is a population based procedures, we need to examine population based outcomes to judge results.

Don't mean to sound harsh, but as a physician, I am acutely aware of the limited resources available. We need to use them wisely.

That all makes sense, doc. But I still wonder if we need better information before we take potentially devastating (in)action.

Tim

 

[Steve Williams]

Val

I hear you

I too am a physician. IMO the test,although not perfect gives us something to go by. I have never seen prostate cancer in the presence if a negative PSA. Similar problems in my specialty with diagnosis of ovarian carcinoma with an elevated Ca-125. I have seen carcinoma with a negative test and no carcinoma with an elevated Ca-125

 

[jazdoc]

That all makes sense, doc. But I still wonder if we need better information before we take potentially devastating (in)action.

Tim

Agreed. I hope I was clear on my prior post: we don't have good data about the cost/benefits of PSA screening, yet we do it anyway. This is a wonderful example of how in our society, the medical bias is always toward action. The idea of not treating an indolent cancer is anathema to the populace and physicians alike. I would opine that too much medical care can be as bad as too little...Michael Jackson as an extreme example. Given the resource constraints, we are going to need to start making decisions about which screening tests (and other medical care) make sense.

 

[rbbert]

Also speaking as a physician, I have always thought the PSA was a poor screening test to use for prostate CA. Put simply, both positive and negative predicitve values are too low. Overlooked in the emphasis on uneeded or even harmful treatments is the fact that unless the cut-off value is set unrealistically low, the PSA also misses a substantial number of aggressive prostate cancers. Were it not for the cancer phobia and the bias toward treatment jazzdoc mentioned, the PSA test would never have gained widespread acceptance as a screening test, and I think the US is the only country where it is used as such (although I'm not completely sure about that).

 

[Phelonious Ponk]

The idea of not treating an indolent cancer is anathema to the populace and physicians alike.

An excellent anathema to share.

Given the resource constraints, we are going to need to start making decisions about which screening tests (and other medical care) make sense.

Theoretically impossible to argue with, but I believe the constraints are greatly overstated and the decisions under consideration often the wrong decisions. We need to understand the efficacy of tests like PSA screening and how to act most effectively on the results more than we need private rooms, 5-star materinity wards, brand-name drugs being dispensed in hospitals, 4 MRI machines at 4 different institutions within a 15 mile drive of my 95-year-old dad's home, the uninsured getting the flu treated at ER, etc. etc. There are lot of cost/benefit and treatment/benefit questions in the system and I'd bet PSA screening is nowhere near the top of the list.

Tim

 

[rbbert]

An excellent anathema to share....

Tim

I'd be interested to hear the reasoning leading to this opinion. For me, ignoring something which is asymptomatic and will be an incidental finding at autopsy makes much more sense than poisoning me (for all cancer treatments other than surgery are poisons) or cutting me up.

 

[Steve Williams]

Also speaking as a physician, I have always thought the PSA was a poor screening test to use for prostate CA. Put simply, both positive and negative predicitve values are too low. Overlooked in the emphasis on uneeded or even harmful treatments is the fact that unless the cut-off value is set unrealistically low, the PSA also misses a substantial number of aggressive prostate cancers. Were it not for the cancer phobia and the bias toward treatment jazzdoc mentioned, the PSA test would never have gained widespread acceptance as a screening test, and I think the US is the only country where it is used as such (although I'm not completely sure about that).

rbbert

Have you seen prostate carcinoma in the presence of a negative (less than 4) PSA

 

[Steve Williams]

I'd be interested to hear the reasoning leading to this opinion. For me, ignoring something which is asymptomatic and will be an incidental finding at autopsy makes much more sense than poisoning me (for all cancer treatments other than surgery are poisons) or cutting me up.

and so with those indolent carcinomas comes more than regular screening to make certain metastases have not occurred. IOW this involves the need for regular screening to make certain that something in situ does not become metastatic

 

[cjfrbw]

I had a friend who died a little over two years ago. Maybe seven years prior, he was diagnosed with PC, and "watchful waiting" was one of the recommenndations.

The problem with the psychology of cancer, is that people fail to regard it a part of the body's ecology, balance and resistance. They think that cancer is either "all there" or "all gone", which never is exactly the case. Issues of dormancy, indolence and even the body contracting and possibly curing itself of various cancers doesn't seem to enter into thought. The body's ecology may entertain all kinds of variations of potentially cancerous cells at any given point in time, which fail to advance or are simply contained. Symptomatic cancers exist when the containment fails. Once prostate cancer metastasizes, you are a goner. The issue seems to be one of containment and monitoring rather than always immediate radical treatment.

My friend chose to have it removed to "get it all out of there", with subsequent extreme pain and various morbiditie, then died of several other things about the age of 76. He probably would never have suffered a pang from the prostate cancer had he just let it be.

 

[mep]

I’m just fed up with all of the medical advice that changes from one day to the next. One day something saves your life, the next day it kills you. I’m sick of watching the nightly news and getting maybe two minutes of news and at least 5 minutes of medical commercials for products whose possible side effects all include the word “death.”

I have a female doctor who gives me a physical every year and I’m not sure she would know a prostrate from a hemorrhoid. We go through the charade every year where she acts like she knows what she is doing and I pretend she does too. I guess it beats the old days at the shipyard where we had mandatory yearly physicals and if you were unlucky enough to have old Doc Crandle get of a hold of you with his fingers that were the size of Louisville Slugger baseball bats and you were always looking around to make sure he didn’t have both hands on your shoulders.

In summary, I’m just sick of getting never-ending conflicting medical advice and I’m tired of the drug companies and insurance companies calling all the shots.

 

[jazdoc]

I’m just fed up with all of the medical advice that changes from one day to the next. One day something saves your life, the next day it kills you. I’m sick of watching the nightly news and getting maybe two minutes of news and at least 5 minutes of medical commercials for products whose possible side effects all include the word “death.”

I have a female doctor who gives me a physical every year and I’m not sure she would know a prostrate from a hemorrhoid. We go through the charade every year where she acts like she knows what she is doing and I pretend she does too. I guess it beats the old days at the shipyard where we had mandatory yearly physicals and if you were unlucky enough to have old Doc Crandle get of a hold of you with his fingers that were the size of Louisville Slugger baseball bats and you were always looking around to make sure he didn’t have both hands on your shoulders.

In summary, I’m just sick of getting never-ending conflicting medical advice and I’m tired of the drug companies and insurance companies calling all the shots.

Hey Mark

I empathize with your frustrations regarding how the media covers medicine. The nature of science is constant change and continued challenge to even our most closely held understandings. Deeper understanding is usually not a revolutionary bolt out of the blue, but rather incremental and with one step back for every two forward. I'm old enough to remember when the treatment of choice for peptic disease was awful; bland diets, commando surgeries, etc. When someone proposed that the cause was inflammation from an infection, he was laughed at...until he was proven correct and revolutionized treatment with better (and less costly) outcomes.

A lot of the news media reporting is driven by other factors. I remember attending an oncology conference and one of the speakers noted that breast cancer received way more coverage than lung cancer in women. In fact women were 10x more fearful of dying from breast cancer compared to lung cancer; even though the death rate from lung cancer was 10x breast cancer! It's not very sensational to be a health reporter and talk about keeping your weight down, eating a balanced diet, not smoking, regular exercise, driving the speed limit using seat-belts....sigh.

 

[rbbert]

rbbert

Have you seen prostate carcinoma in the presence of a negative (less than 4) PSA

Personally, no, but in patients with prostate cancer about 10% or more (depending on patient age) will have a PSA <4, and 5% <2. In fact for patients between 50 and 59, I think the 5th percentile value for those with prostate CA is about 1.5.

 

[rbbert]

... I'm old enough to remember when the treatment of choice for peptic disease was awful; bland diets, commando surgeries, etc. When someone proposed that the cause was inflammation from an infection, he was laughed at...until he was proven correct and revolutionized treatment with better (and less costly) outcomes.
....sigh.

Vagotomy & pyloroplasty! Or the (in)famous "Blue Plate Special" V&P, cholecystectomy and Nissen fundiplication...; compared to 2 wks of antibiotics and PPI's. Sometimes there are true advances in medicine

 

[Steve Williams]

Well I too am old enough ( sigh) to remember all of those things as well but we are talking cancer now not an H. pylori infection.