The effectiveness of PSA (prostate-specific antigen) screening on reducing prostate cancer mortality has been given a boost with new data from the ERSPC (European Randomised Study of Screening for Prostate Cancer). This shows the true impact to be far higher than previously reported – up to 31%.
Preliminary European Randomised Study of Screening for Prostate Cancer (ERSPC) findings* showed that screening reduced prostate cancer deaths by 20%. This latest ERSPC analysis** corrects for non-attendance and contamination to assess the effectiveness of PSA testing in those men actually screened.
From 1992, the ERSPC study randomized 162,000 men, aged 55 to 69, in seven European countries to either a screening arm or a control group.
Those screened were given a blood test to detect PSA levels: if it was 3.0ng/ml or more, they were offered a biopsy. Screening took place on average every four years. Mean follow-up was nine years.
In any randomised trial, some in the screening arm do not attend and some in the control group inadvertently receive a PSA test (contamination). Contamination makes it difficult to detect differences. This is believed to be one reason why the Prostate Lung, Colon and Ovarian (PLCO) study failed to detect any significant reduction in mortality.
PSA cut off level of 3ng/ml is safer threshold for reducing biopsies
Using retrospective data from the Dutch arm, the ERSPC has shown that using a screening algorithm – an individual risk assessment – alongside PSA testing can reduce the number of unnecessary biopsies. PSA testing is sensitive but not specific, so elevated levels do not necessarily imply cancer. Approximately 30% of detected cancers are non-aggressive – ‘indolent’ or slow growing.
Their findings, published in January 2010’s European Urology suggest that a PSA cut off level of 3ng/ml combined with an individual risk assessment would reduce biopsies by 33%. The majority of cancers potentially missed would be indolent, so there would be no benefit from active treatment. Increasing the PSA cut-off level from 3 to 4 ng/ml may save a similar number of biopsies, but will miss more clinically significant cancers.