Low and high PSA levels treated similarly: study

Men who are diagnosed with low-grade prostate cancer often receive aggressive treatment, says a new U.S report.

The study says that more than 70 per cent of men with low prostate-specific antigen levels (20 nanograms per millilitre or lower) — which often indicate the disease is low-grade — had their prostates removed via radical prostatectomy or received radiation therapy.

"Radical prostatectomy was performed on 44 per cent of men with PSA values of 4.0 nanograms per millilitre or lower, 38 per cent of men with PSA values between 4.1 and 10.0 nanograms per millilitre and 24 per cent of men with PSA values between 10.1 and 20 nanograms per millilitre," according to the authors.

In terms of radiation therapy, the results were comparable. Thirty-three per cent of men with PSA values of 4.0 nanograms per millilitre or lower received radiation, versus 40 per cent of men with PSA values between 4.1 and 10.0 nanograms per millilitre and 41.3 per cent of men with PSA values between 10.1 and 20 nanograms per millilitre.

Prostate surgery can damage the nerves that control a man's ability to have or keep an erection, leading to impotence, and can also result in incontinence, according to the Canadian Cancer Society. Radiation can lead to changes in bowel function and urination.

Yet, if a cancer is diagnosed when it is at a low-grade state and localized, the five-year survival rate is almost 100 per cent, according to the study.

The authors believe that a man's PSA level, the current biomarker, should not be viewed in isolation in determining a treatment program. And they feel that lowering the four nanogram per millilitre threshold for biopsy — proposed by some researchers — would lead to overdiagnosis and overtreatment of the disease.

The study, conducted by scientists at the Cancer Institute of New Jersey, located in New Brunswick, N.J., studied 123,934 men using data from the Surveillance, Epidemiology and End Results System, from between 2004 and 2006. It is published in Monday's issue of the Archives of Internal Medicine.