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Too many men get aggressive treatment for prostate cancer - study

Most men who had a low prostate specific antigen or PSA level and low risk prostate cancer received aggressive treatment, according to a new study published in the July 26, 2010 issue of Archives of Internal Medicine.

PSA per se is not a reliable indicator for diagnosis of prostate cancer as a perfectly normal man can produce high levels of PSA while another man who has a low level of PSA can have prostate cancer.  And the PSA test and biopsies indicated for diagnosis of prostate cancer could not tell whether a prostate cancer is benign or aggressive.

Because of this, some doctors believe it is necessary to use biopsy to diagnose the male reproductive disease once a PSA value gets higher than 2.5 nanograms per mL as recommended by major medical organizations like American Cancer Society.

The current study led by Yu-Hsuan Shao, Ph.D., of the Cancer Institute of New Jersey, New Brunswick involved 1123,934 men with newly diagnosed prostate cancer between 2004 and 2006 showed that men with PSA levels below 4 received treatment comparable to that given men with PSA values between 4.0 and 20.0 ng/mL.

The study further found that more than 70 percent of men with PSA values lower than 20 ng/mL had their prostates removed via radical prostatectomy or underwent radiation therapy. And 44 percent of men with PSA values of 4.0 ng/mL or lower received radical prostatectomy.

The authors estimated that if a PSA value between 2.5 and 4.0 ng/mL is considered abnormal, then the number of men with abnormal PSA levels would be about 6 million and 32 percent would be diagnosed with prostate cancer through their needle biopsy.

Among the 1.9 million men with diagnosed prostate cancer, 82.5 percent would receive treatment indicated to cure the disease while only 2.4 percent of these men would have high-grade cancer.

Prostate cancer in most cases is not aggressive and because of this, men aged 70 or older don't have to participate in screening for prostate cancer because they are more likely to die from another health condition than prostate cancer.  Diagnosis and treatment for men in such an age group can do more harm than good, early studies suggest.

Some doctors aruged that early biopsy when PSA reaches the level of 2.5 ng/mL can lead to early diagnosis and early treatment, which reduces the rate of aggressive tumor. The authors write in the report that there is no evidence that delaying biopsy until PSA reaches the level of 4.0 ng/mL would result in an excessive number of non-curable or high grade prostate cancer.

"These results underscore the fact that PSA level, the current biomarker, is not a sufficient basis for treatment decisions," the authors concluded. "Without the ability to distinguish indolent from aggressive cancers, lowering the biopsy threshold might increase the risk of overdiagnosis and over-treatment."

Michael Müntenera and colleagues from University Hospital Zurich reported in the Archives of Internal Medicine in 2010 that biopsy delayed until after PSA reached 4.0 ng/mL only increased one case of high grade prostate cancer out of 100 prostate cancer cases while early biopsy at 2.5 ng PSA /mL would subject 73 percent more men to the invasive diagnosis,leading to over-diagnosis and excessively aggressive treatment for insignificant cancers.

The authors' organizations lowered the threshold of PSA for prostate biopsy from 4 to 2.5 ng per mL in 1998. The authors wanted to know how the early diagnosis would affect the profile of tumor characteristics and the detection rate for two PSA thresholds.

In the study, 8-core prostate biopsy was performed in 214 men aged 62.0 on average whose PSA was between 2.5 and 4 ng per mL and 292 men aged 63.2 years whose PSA was between 4 and 10 ng/mL.  Overall, 120 cancers were detected in 506 patients (23.7 percent).

The researchers concluded that "Lowering the PSA threshold for prostate biopsy from 4 to 2.5 ng/ml results in a substantial increase in the number of men who undergo biopsy and may result in an increased detection of potentially insignificant cancers. If total PSA alone is used to determine the need for prostate biopsy, the disadvantages of this lower threshold probably outweigh its potential benefits."