Featured Research

from universities, journals, and other organizations

Some Men With Low PSAs Still Have Prostate Cancer

Date:
May 27, 2004
Source:
NIH/National Cancer Institute
Summary:
Men with low PSA (prostate specific antigen) levels on screening tests can still have prostate cancer, according to a study released today by scientists from the National Cancer Institute (NCI), part of the National Institutes of Health, and the Southwest Oncology Group, an NCI-funded network of researchers.

Men with low PSA (prostate specific antigen) levels on screening tests can still have prostate cancer, according to a study* released today by scientists from the National Cancer Institute (NCI), part of the National Institutes of Health, and the Southwest Oncology Group, an NCI-funded network of researchers. In this study, prostate cancers were detected by biopsy in men with normal PSA levels.

"The good news is that the vast majority of these cancers were low and intermediate grade, which often are not clinically significant," said Leslie Ford, M.D., associate director for clinical research in NCI's Division of Cancer Prevention, who participated in the research.

"This was the first systematic study of men with PSA levels from 0 to 4 nanograms per milliliter (ng/ml). It shows that cancer of the prostate can be present in men with 'normal' PSAs," said Ian Thompson, M.D., University of Texas Health Science Center at San Antonio, who led the study. Doctors often use the value of 4.0 ng/ml or greater as the trigger for further investigation, such as a prostate biopsy. A PSA level below 4.0 is generally considered normal.

Prostate cancer clinicians often say that men are much more likely to die with prostate cancer than from it. According to recent autopsy studies, many men over age 50 have early, undiagnosed prostate cancer. Clinicians concur that most early cancers remain harmless, though some may progress to clinically significant disease.

The 2,950 men in this study were from the "control arm" of the Prostate Cancer Prevention Trial (PCPT), an NCI-funded study that found in 2003 that the drug finasteride reduced by 25 percent a man's chances of getting prostate cancer.

Men in the control arm were given a placebo, or sugar pill, instead of finasteride and, like the men on the finasteride arm, received annual prostate screening for seven years with a PSA test and a digital rectal exam (DRE). All men in PCPT entered the trial at age 55 or above, had an initial PSA level of 3 ng/ml or less, and a normal DRE. All were asked to undergo an end-of-study prostate biopsy. The report released today focused on men at low risk of having prostate cancer––the 2,950 men on the placebo arm who had normal DREs and PSAs less than or equal to 4 ng/ml for the seven-year study duration.

Since the late 1980s, PSA tests have been widely used in the United States in an attempt to detect prostate cancer at an early stage. However, PSA testing has never been proven to reduce the risk of dying from prostate cancer. Not all prostate cancer detected by PSA screening is clinically relevant and, therefore, screening carries a risk of "over-diagnosing" the disease, which could lead to unnecessary surgery or radiation therapy. Thus, PSA testing is not a universally recommended screening procedure. An ongoing NCI study is addressing the issue of whether PSA screening reduces the risk of death from prostate cancer.

"The main study finding was that 15 percent of the men in the PCPT control arm had a positive end-of study biopsy despite having PSA levels below 4 ng/ml and normal DREs throughout the study," said Thompson.

Importantly, the study also found that only 2.3 percent of men in the PCPT control arm with PSA levels of 4 ng/ml or less had high-grade cancers. For men with a PSA of 2 or lower, the chance of having a high-grade cancer was even lower––1.4 percent. Grade was measured by Gleason score, a system that ranks tumors from 2 to 10 based on their appearance under the microscope. High-grade tumors––Gleason scores of 7 to 10––often grow more quickly and may be more likely to spread than lower-grade tumors.

Gleason scores of the highest grades––8 or 9––were found in only seven participants, or 0.2 percent of men in the PCPT control arm. Most of the men with prostate cancer, 349 of them (78 percent), had Gleason scores of 5 or 6.

"Most of these men would not have been diagnosed if they had not taken part in this study, since biopsies are not routinely performed in men with such low PSA levels," said Ford.

"We need better methods to distinguish the harmless, slow-growing cancers from the more aggressive ones," continued Ford. "If more biopsies are performed at lower PSA levels, more cancers will be found and treated. But some men would undergo treatment, and the risks associated with it, for tumors that would never have been clinically significant."

Treatment for prostate cancer can sometimes lead to impotence, urinary incontinence, and other problems, causing a substantial health burden for men.

"Lowering the PSA threshold for proceeding to prostate biopsy would increase the risks of overdiagnosing and overtreating clinically unimportant disease," said Thompson.

NCI-funded researchers are looking for ways to determine which men harbor aggressive tumors. The NCI Early Detection Research Network (EDRN) has a Prostate Collaborative Group, which is applying a variety of strategies to find ways to detect prostate cancer early. Some scientists are using the new tools of genomics and proteomics to look at how gene expression patterns and proteins in the blood may differ in men with aggressive tumors vs. those with slow-growing ones.

"There is a great need for methods, beyond tumor grade, to better predict which men have prostate cancers requiring treatment," said Thompson.

Prostate cancer is the most common cancer in men, after skin cancer. It estimated that approximately 230,110 men in the United States will be diagnosed with the disease this year, and about 30,000 men will die from it.

# # #

For more information about cancer, visit the NCI Web site at http://www.cancer.gov or call NCI's Cancer Information Service at 1-800-4-CANCER (1-800-422-6237).

###

* Thompson IM, Pauler DK, Goodman PJ, Tangen CM, Lucia MS, Parnes HL, Minasian LM, Ford LG, Lippman SM, Crawford ED, Crowley JJ, Coltman CA. Prevalence of Prostate Cancer among Men with a Prostate-Specific Antigen Level less than or equal to 4.0 ng per Milliliter. New England Journal of Medicine, May 27, 2004; 350(22):2239-2246.


Story Source:

The above story is based on materials provided by NIH/National Cancer Institute. Note: Materials may be edited for content and length.


Cite This Page:

NIH/National Cancer Institute. "Some Men With Low PSAs Still Have Prostate Cancer." ScienceDaily. ScienceDaily, 27 May 2004. <www.sciencedaily.com/releases/2004/05/040527081209.htm>.
NIH/National Cancer Institute. (2004, May 27). Some Men With Low PSAs Still Have Prostate Cancer. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2004/05/040527081209.htm
NIH/National Cancer Institute. "Some Men With Low PSAs Still Have Prostate Cancer." ScienceDaily. www.sciencedaily.com/releases/2004/05/040527081209.htm (accessed July 29, 2014).

Share This




More Health & Medicine News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Ebola Virus Threatens West Africa

Deadly Ebola Virus Threatens West Africa

AP (July 28, 2014) West African nations and international health organizations are working to contain the largest Ebola outbreak in history. It's one of the deadliest diseases known to man, but the CDC says it's unlikely to spread in the U.S. (July 28) Video provided by AP
Powered by NewsLook.com
$15B Deal on Vets' Health Care Reached

$15B Deal on Vets' Health Care Reached

AP (July 28, 2014) A bipartisan deal to improve veterans health care would authorize at least $15 billion in emergency spending to fix a veterans program scandalized by long patient wait times and falsified records. (July 28) Video provided by AP
Powered by NewsLook.com
Two Americans Contract Ebola in Liberia

Two Americans Contract Ebola in Liberia

Reuters - US Online Video (July 28, 2014) Two American aid workers in Liberia test positive for Ebola while working to combat the deadliest outbreak of the virus ever. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins