Dr. Peter Black (biography and disclosures)
What I did before
Screening for prostate cancer has been conducted by many general practitioners and most urologists for years without level one evidence supporting its use. Most of the data on which we base our screening practices is indirect and not definitively causally linked to the decrease in mortality that has been observed in prostate cancer in the last 15 years. Critics pointed to the anxiety associated with an elevated PSA, the potential complications of prostate biopsy and the risks of over detection and over treatment of prostate cancer.
What changed my practice
It was hoped that some of the controversy around PSA screening would be put to rest with the completion of two large prospective randomized trials. Interim analyses were published from both trials in 2009. The Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial randomized 76,693 men in 10 U.S. centres to PSA screening versus “usual practice”. The analysis after a median of 7 years revealed no difference in rates of survival from prostate cancer.1
The European Randomized Study of Screening for Prostate Cancer (ERSPC) randomized 182,000 men in 7 countries to screening versus no screening. This trial revealed a 20% decrease in mortality from prostate cancer after a median of 9 years in the screening arm.2
The PLCO study is criticized for the high contamination in the “usual practice” group – 52% of patients in this arm received PSA screening during the study. Also, the follow-up was relatively short. The European study is criticized because screened patients were more likely to have their prostate cancer treated at a tertiary care centre, although the authors have shown that cancers were treated similarly when adjustments are made to control for the stage distribution. The biggest point of contention in this study, however, is that 1410 patients needed to be screened and 48 needed to be treated to save one death from prostate cancer. These numbers are comparable with the numbers needed to screen for other cancers (for example: 800-1700 for mammography and 1200 for fecal occult blood to prevent one death from breast and colorectal cancer, respectively). The number needed to treat, however, is very high, and compares unfavourably with breast cancer, for example, which is generally estimated between 10 and 15.
What I do now
The controversy around PSA screening persists, as the studies are interpreted by different parties as either supporting or detracting from the argument for prostate cancer screening. The mandate remains in large part the same – we must provide our patients with the necessary facts for them to make an informed decision whether they would like to be screened or not – but we now have much higher quality information to offer our patients in this decision process.
From the urologist’s perspective, it would appear that two key factors on the horizon are going to swing the pendulum strongly in favour of PSA screening: 1.) As the screening studies mature, the numbers needed to screen and to treat are going to come down markedly, as is evident in a recent publication from Sweden3, so that the cost, both in financial terms and with regard to potential patient morbidity from screening, will be drastically reduced; and 2.) We must learn to disconnect the diagnosis of prostate cancer from its automatic treatment. Many patients that we have treated with surgery or radiation therapy in the past are suitable for active surveillance. If we are able to limit treatment to only those cancers that need treatment in order to enhance the quality and longevity of the individual patient’s life, PSA screening will become a more valuable tool.
References: (Note: Article requests require a login ID with the BC College of Physicians website or with UBC)
- Andriole GL, Bostwick DG, Brawley OW, et al: Effect of dutasteride on the risk of prostate cancer. N Engl J Med 362:1192-202, 2010 (View Article with CPSBC or with UBC )
- Schroder FH, Hugosson J, Roobol MJ, et al: Screening and prostate-cancer mortality in a randomized European study. N Engl J Med 360:1320-8, 2009 (View Article with CPSBC or with UBC)
- Hugosson J, Carlsson S, Aus G, et al: Mortality results from the Goteborg randomised population-based prostate-cancer screening trial. Lancet Oncol, 2010 (View Article with CPSBC or with UBC)
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This is a great program for CME!
agree that we must disconnect diagnosis with automatic treatment
when I do psa screening I usually do what the above suggests although if the psa has doubled I will refer the patient to an urologist
Thanks for reviewing these studies. Interestingly, the European study was reported differently in the paper. The Sun reported that they did not find any difference with screening.
excellent program with regards to screening as well as definitive treatment for prostate pathology
This is a reasonable addition to an already very confusing subject. Whether it supports or clarifies the need for prostate cancer screening is debatable. However it certainly supports the need much increased research on the subject as well as quite obviously improvement in the PSA test.
Interesting review but I would like Dr. Black to spell out a bit more what he does in regard to this screening practice. Do you recommend universal screening or not, and to which patients and age groups?. Do you always advise DRE and PSA testing when screening?
Thanks.
I must confess that after reading this article I remain as confused as ever. Ther is no doubt that prostate cancer kills some men but screening for these aggressive tumours appears problematic. The confounding thing is that most men after a certain age histologically have prostate cancer if they are biopsied but the vast majority do not die of prostate cancer. The “treatment” of prostate cancer has a very high morbidity and I am still concerned that even after diagnosing cancer that we aren’t able to treat very effectively the aggressive cancers….
Interesting article. I will definitely give more thought to my use of PDA as a screening test
DRE and PSA screening are part of my routine on all men after the age of 50. At least we will have a base line to follow. I remember when screening mammography and pap smears were considered unnecessary and the government questioned their coverage. Who would challenge that now?
WE should always consider the ultimate outcome expectation of the individual patient before ordering any tests or treatment that carries any “side-effects” or collateral morbidity. What is the point of doing the screening test, finding it positive, and subjecting the patient to invasive treaments when he/she is over 85 and fully enjoying his/her life. A very large population of elderly man harbours a prostate cancer without much symptom or suffering and may die of something else.
I agree with Ron, this article left me wanting more information on who and how often/when to screen.
Problem is this is not age stratified and prostate cancer in a younger man- who may benefit from modest rises in PSA is pitted against elderly men who may have a more benign form of cancer.
Having seen a very good friend with an elevated PSA get screened and evaluated and then sent to surgery- in the nick of time- mind you- no spread outside the capsule- He remains in good health! If not PSA screen he would- likely be facing mets and death. Given he and his wife are my son’s godparents- not an outcome desired.
There is a VERY real personal stake in all these studies. For the slight statistical trender- it can be a life saver.
for family practice docs very bonded to our pts-eh- I ask:
So you tell your patient that evidence is ‘iffy’ about sending for PSA testing. And two years later that pt has advanced prostate cancer. That is what we have to del with. Real life sits- not stats over a
large population that may not reflect ours.
agree entirely with Lora Aller. This is especially true in a small town where we see our patients on the street and at every event we attend. There is nothing which quite matches the small gnawing feeling one gets every time we meet a patient, or a relative, whose cancer we missed – for whatever reason.
I always ask the pt if he wants a DRE and PSA. I usually look at the trend over time, unless the first PSA is already elevated. Then I refer to urologist.
Tough decisions. Kind of a catch 22.
Also not all patiemts understand the proper meaning of a screening test.
I do use DRE and PSA in every man above 50 and below 75yoa.
BPH, porstatitis and other confusing diagnosis make the scenario even more troublesome.
I do always send to an urologist who has longer experience in practice and that weigh all the evidence.
Let me take this opportunity to respond to some of the comments.
One participant suggests referring patients for urologic evaluation when the PSA has doubled – this is an arbitrary cut-off that will miss many cancers and is not backed by data. If a change over time is going to be used, and increase of 0.35 in one year if the PSA is less than 4 or 0.75 if the PSA is greater than 4 has some validity.
Dr Zapf-Gilje points out the disparity between what I have suggested in the original contribution and what was reported in the media with regards to the large screening studies. This was indeed noted by many urologists and is not easy to explain. The American study was negative, and this seems to have been the focus of the headlines. They also chose to interview some prominent critics of PSA screening but no proponents. In my opinion the media reports were not balanced.
Dr Potter-Cogan asks for more concrete recommendations for screening. The core recommendation is to screen every man over the age of 50 with more than 10 years life expectancy. In my own practice I recommend an initial PSA at 40 or soon thereafter. If it is less than the age-appropriate median 0f 0.7, I check again in 5 years. If greater, I check annually. This goes along with the NCCN guidelines and is based on the fact that the risk for subsequent diagnosis of prostate cancer is greatly increased in men with a PSA greater than the age-appropriate median. In addition, men with a family history (father/brother/paternal uncle) and black men are offered screening starting at age 40. One aspect that is likely to change in the future is the frequency of screening – annual screening is likely overkill and every 2nd or 3rd year is probably adequate. In the European study, screening was every 4th year. Currently, however, the recommendation is for annual screening. I always do a DRE at the same time. There are clearly cancers that are palpable despite a normal PSA. The DRE is also easy to do and free – although uncomfortable for patients.
A couple of participants comment on the continued confusion in this field. We do not have all the answers – and there are prominent voices that still go against screening. The take home message should be that there is evidence that supports screening and its ability to save lives – and the emerging evidence with longer follow-up is that this can be done with acceptable “collateral damage” (measured as the number needed to screen and the number needed to treat to save one life). What remains is further fine-tuning of what we do. The 85 year old patient should not be part of the discussion – he does not need screening. The 75 year old is much more difficult. Furthermore, whether screening is of any benefit for the most aggressive cancers remains to be shown – likely most benefit is with the intermediate risk patients. There is a long list of treatments for aggressive prostate cancer that prolongs survival and two recent publications highlight the remarkably good survival in men with high risk non-metastatic disease – but the question remains whether detecting them earlier makes a difference. The true problem is with the low risk patients, who do not need treatment of any kind. One of the most important unresolved questions in prostate cancer research is which patients are suitable for active surveillance.
I would say that we all are very bonded to our patients – not just GPs and not just in small towns. Every screening test, every biopsy and every treatment must be weighed very carefully. “Missing” a prostate cancer due to lack of screening is troublesome – yet there has been no evidence until recently that detecting that cancer any sooner with screening would have made a difference. This is incomprehensible to patients ultimately diagnosed with prostate cancer, who tend to be the biggest proponents of the test, yet most of the non-urologic medical community questions its value. We have to be careful with emotional arguments regarding individuals. What if the family friend or the patient we pass in the street had a small volume Gleason 6 prostate cancer and is now incontinent and impotent after radical prostatectomy? He still believes PSA saved his life, but we know better.
The age issue touched upon by Dr Aller is not straightforward. The risk of having cancer and the risk of having a more aggressive cancer increase with age – this is part of the reason why it is difficult to determine an age above which screening should be discontinued. This is also why age-dependent PSA cut-offs are mostly not used, since they will lead to more missed cancers in the older men. The one thing that clearly changes with age is the likelihood of dying from something other than prostate cancer, and this plays heavily into treatment decisions (especially regarding active surveillance). Unfortunately it is difficult to predict this risk in an individual patient.
The new US Preventive Services Task Force (USPSTF) recommendation against screening for prostate cancer only muddies the waters further. I still believe in the utility of the PSA test, but only if discussed with a nuanced intention with patients that respects their individual situations.
Response more informative and useful than article!