GPs over-screening for prostate cancer

Many general practitioners are carrying out unnecessary and potentially harmful screening for prostate cancer, two studies have found.

Prostate cancer, the third most common cause of cancer deaths in New Zealand men after lung and bowel cancers, accounted for 3.85 per cent of all male deaths in 1999, or 552 deaths.

One study was carried out on a range of GPs, and the other was a telephone survey of the experiences of Auckland men with prostate cancer.

The results, published in this month's Medical Journal, found that most GPs were screening for prostate cancer in patients where there was no evidence to suggest the screening would reduce the number of deaths from the disease.

A 55-year-old man having an annual checkup, or requesting advice about screening, would be given a prostate specific antigen (PSA) test by 74 per cent of GPs.

If the man had a family history of prostate or breast cancer, 93 per cent of doctors would give the PSA test.

A form of screening was performed by 97.5 per cent of GPs, and 50 per cent of GPs supported a national screening programme that had "no proven benefit and the potential to cause considerable harm", the report said.

Two-thirds of doctors (62.9 per cent) incorrectly indicated smoking as a risk factor, and 63.6 per cent incorrectly indicated benign growths in the prostate as a factor.

GPs were increasing their screening of men, despite a report written in 1996 by a National Health Committee (NHC) working party that stated there were "significant potential risks associated with confirmatory tests and treatment and the risks outweighed the as-yet unproven benefits of earlier intervention".

The report said many GPs felt pressured to supply the tests by outside groups such as the Prostate Awareness Society, the media, and urologists who encouraged men to seek screening.

Report authors Bruce Arroll, Salil Pandit and Stephen Buetow, said invasive treatments such as surgery could be very harmful.

One study found that 8.4 per cent of men experienced incontinence and 41.9 per cent had erectile dysfunction after radical surgery for clinically localised prostate cancer.

No published trials had found a mortality benefit from screening. The Cancer Society recommended not screening.

- NZPA