Should I have that blood test for Prostate Cancer?

PSA screening

• Understand what the PSA test is

• Identify when it should be used

• Describe the pros and cons of PSA testing

Prostate Cancer

• Commonest cause of cancer in men in the UK• 2nd commonest cause of cancer death in men in the

UK• Average age of diagnosis is 70 – 74 yrs of age• Much less common under 50 yrs of age• Average age of mortality is 80 – 84 yrs of age• 1 in 26 men in the UK will die from Prostate

Cancer

Risk Factors for Prostate Cancer

• Age (strongest risk factor)• Family history – especially if relative

diagnosed before age of 55 yrs– Also link to BRCA 1 and 2 so consider FHx

breast cancer relative

• Black men > 3 times more likely than white men (oriental/asian men lowest risk)

• Diet inconclusive

What is the PSA?

A Glyccoprotein which liquefies semen and aids sperm motility

PSA Testing• ANY man aged over 50 who requests a PSA after careful

consideration should be tested

• Expressed in benign and malignant conditions

• Test benefits– Diagnose cancer before symptoms

– Diagnose at a stage where could be cured or life extended

– Serial measurements may help in diagnosis

• Test limitations– PSA not diagnostic or tumour specific

– False reassurance: 15% of men with a normal PSA will have Prostate Cancer and 2-3% will have high grade Prostate Cancer

– Identification of cancers which may not become clinically evident in the patient’s lifetime

Stats• Sensitivity (rules diagnosis in)

– 21 % for all prostate cancers– 51 % for high grade prostate cancers– Using a PSA cut off of 4.0

• Specificity (rules diagnosis out)– 91 % for all prostate cancers– Using a PSA cut off of 4.0

• Positive Predictive Value (proportion of men with an elevated PSA who have Prostate Cancer)– 30 % for a PSA level of > 4.0– Less than 1 in 3 men with a PSA of > 4.0 will have Prostate

Cancer detected on biopsy

Conditions for PSA testing• One should not check the PSA (has a half life of 2.2

days)– During an active UTI– If ejaculated within previous 48 hrs (rise of up to 0.8)– If exercised vigourously within previous 48 hrs– Had a DRE within 1 week (although some studies suggest

minimal rise 0.26 –0.4)– Had a Prostate Biopsy within 1 week (rise of 7.9)– Nb 5 Alpha Reductase inihibitors may reduce PSA by 50%

within 6 months

DRE is useful for men with LUTS but not for asymptommatic men

Referrals

• If PSA raised above age specific limit– Refer Urology 2WW

Questions?