A diagnosis of prostate cancer ups the risk of fatal heart attack or suicide

Prostate cancerReceiving a diagnosis of prostate cancer is a very stressful and upsetting event, so much so that some men go on to have a fatal heart attack or kill themselves.

Two pieces of research by the same study group, one conducted in 340,000 men in the US and the other in 170,000 men from Sweden, have found that the risk of dying from a heart attack is raised by 2 to 11 times in men with a diagnosis of prostate cancer.

In addition, the risk of suicide in the first year after diagnosis in American men with prostate cancer was 40% higher than the national average and the risk in the first three months 90% higher. Astoundingly, Swedish guys were twice as likely to kill themselves in the first three months after diagnosis than men who were cancer free.

Interestingly, the US study found that the risk of suicide was only raised between 1979 and 1992, before the widespread use of screening to detect prostate cancer early.  There was no link between prostate cancer and suicide once screening, known as prostate-specific antigen (PSA) testing, was being used across the board.

So does this mean that screening for prostate cancer reduces the risk of suicide after a diagnosis? The authors think so, suggesting that early screening detects less aggressive tumors that are still treatable, thus less stress inducing.

On the other hand, the use of PSA testing has long been controversial. Many men will have small prostate tumours that never do them any harm and the test itself isn’t very reliable, so screening is associated with overdiagnosis and overtreatment.

By extension, some studies reckon that routine testing for prostate cancer causes undue stress and anxiety among patients who do not understand the implications of an abnormal result.  In fact, the Swedish study did not find any difference in suicide risk between the pre-screening era and after screening had been introduced.

This post was chosen as an Editor's Selection for ResearchBlogging.org

The authors aren’t sure about this difference between their two studies, admitting “The reason for this discrepancy is unclear.” However, it could potentially be caused by the large number of nonaggressive prostate cancers diagnosed during the later years in the US study or improved access to emotional support after diagnosis come the late 80s, which might have lessened despair among patients and reduced their suicide risk.

“These results add to the complex debate of pros and cons of extensive prostate-specific antigen testing and the many nonlethal prostate cancers thus detected,” say the authors.

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Fall K et al. (2009) Immediate Risk for Cardiovascular Events and Suicide Following a Prostate Cancer Diagnosis: Prospective Cohort Study PLoS Medicine 6 (12). DOI: 10.1371/journal.pmed.1000197

Fang F et al. (2010). Immediate Risk of Suicide and Cardiovascular Death After a Prostate Cancer Diagnosis: Cohort Study in the United States JNCI Journal of the National Cancer Institute DOI: 10.1093/jnci/djp537

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When NOT to screen for cancer

Cancer screeningAnnual screening for prostate cancer may not be required in many elderly men, whereas routine screening for breast cancer should probably never have been implemented, say two separate studies published this week. These studies raise questions as to whether regular screening for common cancers is really necessary and, if so, in which groups.

In the first study, due for publication in the Journal of Urology, the authors assessed 849 men aged from 40 to 92 who had been followed up for 10 years as part of the Baltimore Longitudinal Study on Aging.

During this time period, the men had undergone an average of four tests to measure prostate specific antigen (PSA) levels. PSA level in the blood is used to screen for prostate cancer: if a man has a blood PSA level of of 4.0 ng/ml or higher, it is likely that he has prostate cancer.

The authors found that in a subgroup of men aged 75 years or older who had a PSA level of below 3.o ng/ml – well within the normal range – none died of cancer and only one developed high-risk prostate cancer.

In the US and the UK, men over the age of 50 are advised to undergo annual prostate cancer screening. The findings of this study imply that routine screening may not be needed those who are over 75 and have a normal PSA level, as such individuals are unlikely to die of or experience aggressive prostate cancer during their remaining life. Even if PSA levels indicate that a man over 75 DOES have prostate cancer, it’s likely that he’ll die of something else rather than the malignancy.  In such cases men could forgo risky therapy and avoid the nasty side effects that can seriously affect quality of life.

Speaking to Reuters, Dr H Ballentine Carter of Johns Hopkins University in Baltimore, one of the researchers contributing to the study said, “For the overwhelming majority of men over age 75, discontinuing PSA screening is probably a very safe thing to do”.

As for women, an analysis in the BMJ has highlighted the risks associated with mammography – including a high rate of false positives – and suggests that in many cases the risks inherent in routine screening for breast cancer outweigh the benefits.

The authors of this study argue that the NHS Cancer Screening Programmes leaflet about mammography, Breast screening: the facts, is unbalanced in its portrayal of the positives and negatives of screening and constitutes “one sided propaganda about breast screening”.

They suggest that the leaflet overplays the benefits of breast cancer screening, such as the possibility that screening leads to fewer mastectomies.  Various studies indicate that the number of mastectomies actually increases when screening is introduced, they point out. The authors even dispute the statement that screening saves lives, highlighting trials showing that screening does not decrease total cancer mortality.

The authors also opine that the leaflet downplays the risks of breast cancer screening, like the possibility of being overdiagnosed, which with mammography is ten times more likely than being accurately diagnosed.  “No mention is made of the major harm of screening – that is, unnecessary treatment of harmless lesions that would not have been identified without screening,” they write.

The analysis concludes that breast cancer screening is associated with less benefit and substantially more harm than previously thought and that mammography screening programmes would probably not have been initiated if the individuals who wrote the policies 20 years ago had had the evidence available today.

So should prostate cancer and breast cancer screening programmes be cut back? Doing so would avoid the consequences of false positives and would save health care providers millions of pounds in diagnostic costs.

What do you think? Would you stick to your yearly screening appointments regardless of the risk of being misdiagnosed and subjected to unneccessary treatment, just in case one day screening does catch a malignant but treatable lesion that would have otherwise been missed? Or would you rather steer clear of the hassle of screening and the stress of a false alarm?

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