New model predicts likelihood of prostate cancer prior to biopsy

August 25, 2003

PORTLAND, Ore. -- A new, simple predictive model could reduce the number of unnecessary prostate biopsies by 24 percent without sacrificing cancer detection, according to a study to be published in the Oct. 1 issue of CANCER and available online beginning Aug. 25 at the Wiley InterScience Web site.

"While current prostate cancer screening practices are good at helping us find patients with cancer, they unfortunately also identify many patients who don't have cancer. Three out of four men who receive a prostate biopsy after an abnormal prostate screening test do not have cancer at all," said Mark Garzotto, M.D., principal investigator, member of the OHSU Cancer Institute and director of urologic oncology at the Portland Veterans Affairs Medical Center. "So the challenge has been to develop a model that both predicts which men will have prostate cancer and spares men without prostate cancer from unnecessary biopsies."

Prostate cancer is the most common cancer in men and the second leading cause of cancer-related death in American men. Overall, roughly one in six men will develop prostate cancer during his lifetime. Prostate biopsy can be a source of patient discomfort, bleeding and infection, and can burden the health care system with extra costs.

This new model -- a nomogram -- predicts the detection of prostate cancer in men with a prostate specific antigen (PSA) level of less than or equal to 10 ng/ml. Prostate cancer screening using a PSA test has been associated with a decline in prostate cancer deaths in the United States.

About 10 percent of men who are tested will have an elevated PSA. However, PSA becomes specific only when it exceeds 10 ng/ml. When the PSA is modestly elevated from 4 to 10 ng/ml, which it is in the majority of cases, it is associated with cancer in about 25 percent of men who are biopsied. Attempts to develop predictive models for PSA values less than 10 have been made, but to date they have been unable to identify low-risk groups that do not need prostate biopsy.

"Our model accurately predicts prostate cancer in men whose PSA level is below 10 ng/ml, a level at which the PSA test can't tell us who doesn't have cancer," Garzotto said.

The nomogram is based on easily accessible laboratory, clinical and transrectal ultrasound (TRUS) data. The nomogram itself is a graphic made up of lines representing individual risk factors marked off to scale and arranged in such a way that a numeric representation of the likelihood of cancer can be easily calculated. For example, a total score of 6.8 corresponds to a 10 percent likelihood of positive prostate biopsy.

In developing the nomogram, study authors identified independent risk factors associated with malignant biopsies. The data revealed four independent predictors of a positive biopsy: elevated PSA density, abnormal digital rectal exam, abnormal/hypoechoic transrectal ultrasound and age greater than or equal to 75. Patients younger than 75 with normal DREs, normal TRUS and normal PSAD of less than 0.09 had a less than 5 percent chance of having malignancy on biopsy and, therefore, were low-risk patients. A patient aged 75 years or older who had an abnormal DRE, abnormal/hypoechoic TRUS and an abnormal PSAD value of 0.30 had a 59 percent chance of having prostate cancer.

"Not only could this model reduce unnecessary biopsies, it could be a useful tool in preparing patients for possible outcomes before the biopsy," said Garzotto, who posted a copy of the nomogram in his clinic next to the ultrasound machine, where he finds it most useful.
Study results are available via Wiley InterScience at beginning Aug. 25. Note to editors:
An electronic Power Point slide of the nomogram is available upon request.

Mark Garzotto, M.D., is an assistant professor of surgery (urology) in the OHSU School of Medicine, director of urologic oncology at the Portland Veterans Affairs Medical Center, and a member of the OHSU Cancer Institute.

To access all OHSU news releases, visit

Oregon Health & Science University

Related Prostate Cancer Articles from Brightsurf:

Low risk of cancer spread on active surveillance for early prostate cancer
Men undergoing active surveillance for prostate cancer have very low rates - one percent or less - of cancer spread (metastases) or death from prostate cancer, according to a recent study published in the Journal of Urology®, an Official Journal of the American Urological Association (AUA).

ESMO 2020: Breast cancer drug set to transform prostate cancer treatment
A drug used to treat breast and ovarian cancer can extend the lives of some men with prostate cancer and should become a new standard treatment for the disease, concludes a major trial which is set to change clinical practice.

Major trial shows breast cancer drug can hit prostate cancer Achilles heel
A drug already licensed for the treatment of breast and ovarian cancers is more effective than targeted hormone therapy at keeping cancer in check in some men with advanced prostate cancer, a major clinical trial reports.

The Lancet: Prostate cancer study finds molecular imaging could transform management of patients with aggressive cancer
Results from a randomised controlled trial involving 300 prostate cancer patients find that a molecular imaging technique is more accurate than conventional medical imaging and recommends the scans be introduced into routine clinical practice.

Common genetic defect in prostate cancer inspires path to new anti-cancer drugs
Researchers found that, in prostate cancer, a mutation leading to the loss of one allele of a tumor suppressor gene known as PPP2R2A is enough to worsen a tumor caused by other mutations.

First prostate cancer therapy to target genes delays cancer progression
For the first time, prostate cancer has been treated based on the genetic makeup of the cancer, resulting in delayed disease progression, delayed time to pain progression, and potentially extending lives in patients with advanced, metastatic prostate cancer, reports a large phase 3 trial.

Men taking medications for enlarged prostate face delays in prostate cancer diagnosis
University of California San Diego School of Medicine researchers report that men treated with medications for benign prostatic hyperplasia (enlarged prostate) experienced a two-year delay in diagnosis of their prostate cancer and were twice as likely to have advanced disease upon diagnosis.

CNIO researchers confirm links between aggressive prostate cancer and hereditary breast cancer
The study has potential implications for families with members suffering from these types of tumours who are at an increased risk of developing cancer.

Distinguishing fatal prostate cancer from 'manageable' cancer now possible
Scientists at the University of York have found a way of distinguishing between fatal prostate cancer and manageable cancer, which could reduce unnecessary surgeries and radiotherapy.

Researchers find prostate cancer drug byproduct can fuel cancer cells
A genetic anomaly in certain men with prostate cancer may impact their response to common drugs used to treat the disease, according to new research at Cleveland Clinic.

Read More: Prostate Cancer News and Prostate Cancer Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to