Moffitt Cancer Center Researcher Helps Develop Prostate Cancer Testing, Treatment Guidelines
They also looked at studies on positive cores from biopsies and the extent to which core results could be used to develop criteria for treatment. Reports have shown the predictive value of positive biopsy cores, but the frequency for performing prostate biopsies remains controversial for outcomes of active surveillance patients, Pow-Sang said.
“Biopsies are not without consequences,” he said. “Rectal bleeding and serious infectious complications from frequent biopsies need to be considered.”
Additionally, no standard protocol exists, and controversy remains, for the frequency of PSA testing and the digital rectal exam for patients who are under active surveillance.
“PSA screening is the only test we have,” said Dr. William Catalona, a professor of urology at Northwestern University. “The great majority of doctors who deal with prostate cancer patients believe that the task force underestimated the benefits and overestimated the harms. Perhaps it is because none of the Task Force members were urologists.”
“There is no mention of the dramatic decline in the number of men with advanced prostate cancer,” said Dr. Patrick Walsh, professor of urology at Johns Hopkins University. “In 1990, 21 percent of men at diagnosis had metastatic prostate cancer to bone. Today it is 4 percent. This is clearly a dramatic effect of PSA testing.
“[The new recommendations] fail to recognize that in the absence of PSA testing, a man will not know that he has the disease until he has symptoms, at which time the cancer is too far advanced to cure,” Walsh said.
And Dr. Gerald Andriole, chief of urology at Washington University School of Medicine, called the task force’s recommendations “too draconian on categorically dismissing PSA.”
“In some respects we have not been using PSA as well as we could,” Andriole said. “However, to post a headline that says ‘No More PSA Testing’ is throwing the baby out with the bathwater.”
“Current guidelines vary,” Pow-Sang said. “There are recommendations that the PSA and digital rectal exam should be performed every three to six months, or the PSA every three months and the digital rectal exam every six months. The frequency of biopsies is also variable, from once a year to up to every three years.”
New potential tools
Pow-Sang and Buethe also report that a new tool, the PCA3 urinary marker, may be useful. PCA3 is a urine test used to quantify copies of the known prostate cancer gene 3. A PCA3 score of 35 or greater is considered possibly malignant. The test is prostate cancer specific and unaffected by prostatitis or benign prostatic hyperplasia, both of which have confounded the results of PSA testing.
The future of active surveillance
“Most studies report that 30 percent of active surveillance-classified men will be reclassified in the short term to clinically significant cancer that may require treatment,” noted Pow-Sang. “Once more, PSA velocity (how quickly the PSA score rises) or PSA doubling time (how often the score doubles) has no clear role in active surveillance.”
When counseling men with early prostate cancer, all treatment options, risks and complications should be discussed, Pow-Sang confirmed.
PSA Testing Boosts Survival
Still, the PSA test is likely not solely responsible for these improvements. More detailed imaging and better treatments also likely play a role in these survival gains. “While not all of these welcome improvements can be attributed strictly to PSA testing, without a doubt it has played a role in extending many lives,” Thompson says in a news release.
PSA testing is controversial. A government task force recently recommended against such screening, but other groups take a softer stance. The American Cancer Society and others state that men should not get a PSA test until they discuss their personal risks and benefits with their doctor.
Otis Brawley, MD, chief science officer at the American Cancer Society, says the survival benefit seen in the new study is likely due to factors other than routine PSA screening.
Changes in imaging technology that better categorize prostate cancers and improved use of drugs also affect survival, he says. As to whether men should or shouldn’t get PSA testing, there is no clear-cut answer. “Men need to be informed of the risks and benefits and make a decision.”
“Active surveillance is a reasonable management strategy for low-risk and very low risk prostate cancer, but allows for continual reassessment and identification of progressive tumors.”
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H. Lee Moffitt Cancer Center & Research Institute