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PSA screening leads to overdiagnosis, often aggressive follow-up

Prostate cancer is a form of cancer that develops in the prostate, a gland in the male reproductive system. According to the American Cancer Society, more than 192,000 new cases of prostate cancer were diagnosed in 2009.

Majority of men diagnosed with low-risk prostate cancer resort to aggressive treatment plans like radiation or radical surgery, increasing their risk of serious side effects, findings of a new study show.

Men with PSA (prostate-specific antigen) levels lower than 4 nanograms per millilitre are less likely to develop high-risk tumors, have their cancers spread outside prostate or have tumors larger than 0.5 cubic centimetres. As a result, they are less likely to benefit from any intervention, researchers aver.

Yet, more than 75 percent of men diagnosed with low-grade prostate cancer undergo aggressive treatment, statistics reveal.

'If we knew for sure everyone with a PSA under 4 would not die of prostate cancer, case closed," Mark N. Stein, medical oncologist at The Cancer Institute of New Jersey and assistant professor of medicine at the UMDNJ-Robert Wood Johnson Medical School, New Brunswick said.

Prostate cancer treatment pattern
To determine the trend of prostate cancer treatment, researchers looked into medical records of nearly 124,000 men, all part of the Surveillance, Epidemiology, and End Results (SEER) database.

The SEER database is picked up from 16 tumor registries and represents about 26 percent of the U.S. population.

Prostate cancer really is "no longer a fatal disease." Even without treatment only a small minority of men diagnosed with early-stage prostate cancer die from the disease.

Among 124,000 men, all of whom were diagnosed with prostate cancer between 2004 and 2006, 14 percent had PSA levels lower than 4 nanograms per millilitre, 73.5 percent had levels between 4.1 and 20 nanograms per millilitre, and 12.5 percent had levels above 20 nanograms per millilitre.

The PSA test picks up the scores of prostate-specific antigen, a protein produced by the prostate. Usually, the higher the PSA value, the higher is the risk of prostate cancer.

On average, most healthy men without prostate cancer record a PSA score of less than 4 nanograms per millilitre.

More aggressive treatments followed
Although 54 percent men with PSA levels below 4 nanograms per millilitre had low-risk cancers, 75 percent had resorted to aggressive treatment plans-- either radical prostatectomy, complete removal of the gland, or radiation therapy, Stein found.

While 44 percent men had a radical prostatectomy, 33 percent underwent radiation therapy.

Treatment based on PSA scores can be perilous
Basing a treatment entirely on PSA scores can be quite a disaster, researchers warn.

As PSA screening picks up all tumors, even benign, it leads to overdiagnosis and additional, but often unnecessary, testing and treatment, researchers say.

It also paves way for painful biopsies, leading to side effects like excessive bleeding and infection.

According to a Swedish research, prostate cancer really is "no longer a fatal disease." Even without treatment only a small minority of men diagnosed with early-stage prostate cancer die from the disease” researchers concluded.

Stein and colleagues suggest ‘active surveillance’ for men with low-risk disease. It involves PSA testing and digital rectal exam every three to six months and biopsy every one to two years.

Collectively, a PSA level of 10 ng/mL or lower, a Gleason score of six or lower, and clinical disease stage T1c or T2a are categorized as low-risk cancers.