March 9, 2001
Volume XXXIV, No. 10



Of Note


UTHSC researchers announce 5-year study of prostate cancer biomarkers

Sidebar: Scientists search for clues in prostate cancer ethnic puzzle

Facts about prostate cancer

Dr. Ian Thompson Dr. Ian Thompson

An ambitious five-year, 10,000-patient effort to improve the screening and detection of prostate cancer was launched March 9 at the Health Science Center.

Dr. Ian Thompson, professor of surgery and chief of the division of urology, is principal investigator of the San Antonio Center of Biomarkers of Risk for Prostate Cancer. The project is known as SABOR.

Males 50 or older are invited to participate. African Americans and other males with a family history of prostate cancer may join the study if they are at least 40. Men who have had prostate cancer are not eligible.

Screenings will be held throughout the city at clinics of the University Health System, the South Texas Veterans Health Care System, Wilford Hall Medical Center, Brooke Army Medical Center, the Cancer Therapy and Research Center, the University Physicians Group, the Barrio Comprehensive Family Health Center and the Ella Austin Health Center.

Prostate Cancer bookcover Dr. Ian Thompson is one of the authors of Prostate Cancer, a book oriented for the layperson.

Interested individuals are invited to call ext. 7-0214 to set up an appointment at the clinic nearest them. Participants will receive annual screenings with prostate-specific antigen (PSA) testing and digital rectal exams. The men will complete dietary surveys at enrollment and give blood samples during the five annual visits.

The National Cancer Institute is funding the study as part of its Early Detection Research Network. Johns Hopkins Hospital in Baltimore is the only other research site for the prostate cancer project. This program will recruit from all ethnic groups with a focus on over-sampling of underserved and minority populations.

"Our ultimate goal is twofold," Dr. Thompson said. "We want to identify men who are at risk of prostate cancer as well as those who have a very low risk - men who might never have to be screened. Second, for men who are at risk of developing prostate cancer, we want to find new methods to prevent the disease. Ultimately, we'd like to put ourselves out of business by preventing the disease entirely."

The SABOR study will evaluate the relationships between diet and prostate cancer. Researchers also seek to show a connection between prostate cancer biomarkers, such as insulin-like growth factor-1, and development of the disease in the research population. Dr. Thompson's team also hopes to discover novel biomarkers.

Cells have unique molecular "signatures" that vary depending upon gene activity and production of proteins and other cellular products. Scientists are interested in the changes of the signature when a normal cell becomes a cancer cell. "We are focusing on these signatures and on ways to apply them to the earlier detection of prostate cancer," Dr. Thompson said.


Scientists search for clues in prostate cancer ethnic puzzle

African-American men develop prostate cancer earlier in their lives and are more likely to die from it than white, non-Hispanic men. Dr. Ian Thompson's research group is seeking answers to this conundrum.

The group's report, "Association of African-American Ethnic Background with Survival in Men with Metastatic Prostate Cancer," was published in the Feb. 7 issue of the Journal of the National Cancer Institute. Dr. Thompson's team applied statistical regression analysis to data from 288 African-American and 975 white men, all with metastatic prostate cancer. The poorer survival of African-American men with this cancer could not be explained by prognostic variables such as higher prostate-specific antigen levels (PSAs) or younger age at study entry.

"We asked very pointed questions to determine why the survival of African-American men with metastatic prostate cancer was so much worse in a study in which the treatment of all men was identical," Dr. Thompson said. "After we corrected for all measurable and known reasons why cancer survival is different, African-American men still had shorter survival than other men in the study. This difference emphasizes the importance of further studies investigating these differences with a goal of causing a fall in number of deaths from the disease."


Facts about prostate cancer

• Prostate cancer is the most common cancer in U.S. men. An estimated 198,100 cases will be diagnosed in 2001.

• It will account for nearly one-third of new cancer cases in men this year.

• An estimated 31,500 U.S. deaths will be attributed to prostate cancer in 2001. Early detection has resulted in a decrease in prostate cancer deaths in recent years.

• Prostate cancer is the second leading cause of cancer death among men (11 percent of deaths) behind lung cancer (31 percent).

• Prostate cancer mortality and incidence rates are higher in African-American men compared to non-Hispanic whites.

• A few reports suggest Asian and Hispanic men have lower incidence and mortality rates, as well.

• Little is known about risk factors and prostate cancer outcomes in Hispanics, who are a major focus of this study. The San Antonio Center of Biomarkers of Risk for Prostate Cancer (SABOR) will generate almost the first data on prostate cancer in Hispanic men.

• The impact of early detection of prostate cancer on mortality rates is not fully understood. Observations in the United States and Canada have noted a fall in prostate cancer mortality beginning about seven years after the widespread dissemination of prostate-specific antigen (PSA) testing.

Sources: SABOR, American Cancer Society