A recent article in the British Medical Journal raised doubts about the value and cost-effectiveness of breast cancer screening (McPherson K BMJ 2010, 341:223-4). This was reported widely in the media, with predictable spin-off articles by some commentators similarly condemning the PSA test for prostate cancer.
It’s true that a single PSA test can provide only limited information about what is going on in the prostate. There are too many false-positive and false-negative results for us to be able to rely on it; and without doubt there are too many men who undergo biopsy unnecessarily.
But we don’t rely on a single test: other factors such as rectal examination, family history, prostate size etc help us complete the picture when deciding whether or not a biopsy is advisable. And regular PSA testing provides a background against which a sudden rise can be judged. A decision can then be made as to whether a biopsy is indicated.
A recent large European prostate cancer screening trial (ERSPC) did confirm that PSA screening resulted in over 20% reduction in mortality – although it also highlighted the risk of over-treatment of small, less aggressive cancers (N Engl J Med 2009; 360:1320-8).
If a low-risk, small volume cancer is detected on biopsy, then it doesn’t necessarily mean you have to have immediate treatment: you can enter into a progreamme of active surveillance so that treatment can be started if and when the cancer grows. For higher-risk cancers, treatment with surgery has been shown in a study from Sweden to reduce the risk of spread of cancer to the skeleton and improve survival.
Nearly 10,000 men die of prostate cancer annually in the UK. Many of them could have been saved, if only earlier earlier diagnosis and effective treatment had been made available to them.