In February 2005, a follow-up analysis of data from PCPT, published online in the journal Cancer, showed that if finasteride were prescribed as a preventive therapy to older men, an estimated 316,760 years of life would be saved over 10 years through the prevention of prostate cancer.

The Original PCPT Study

The PCPT began enrolling men in the study on October 13, 1993. The study ended on May 16, 1997 after 18,882 had been randomized to the study. The men were randomly assigned to take either 5 milligrams of finasteride or a placebo on a daily basis for seven years. The researchers contacted the men two to four times per year for an update on their general health. The men were asked to have a digital rectal exam (DRE) and prostate-specific antigen (PSA) blood test annually. At the end of seven years, men who were medically able and willing were asked to have a needle biopsy of the prostate performed to check for prostate cancer. These end-of-study prostate biopsies began in October 2000.

The analysis of PCPT study data revealed that men in the finasteride group who were evaluated were 24.8% less likely to develop prostate cancer when compared to the men evaluated who were in the placebo group (18.4% of men on finasteride versus 24.4% of men on placebo developed prostate cancer).

The study data also suggest a note of caution. Although the men taking finasteride had fewer prostate cancers, they had an increased number of high-grade prostate cancers (Gleason 7-10) which can spread quickly even if the tumor is small. In the entire group of men assigned to finasteride who were evaluated, 6.4% had high-grade cancers while 5.1% of men evaluated in the placebo group had high-grade cancers. Almost all of the prostate cancers diagnosed during the study were found in an early stage, when they are very treatable. One of the objectives of the PCPT Long Term Follow-up study, discussed above, is to better determine whether finasteride causes more aggressive tumors to develop or whether finasteride affects the appearance of prostate cancers under the microscope leading to a faulty estimate of tumor grade.

Letters announcing study closure and initial findings were mailed out to the men who participated in this study. If you were a participant in the study and you did not receive a study closure notification letter, please contact the clinic or hospital where you participated in the PCPT, or you may contact 1-800-4CANCER (1-800-422-6237) for more information.

PCPT Science Continues: Program Project Grant

Five Southwest Oncology Group Prostate Cancer Prevention Trial ancillary studies were funded in spring 2005 through a program project (P01) grant. The project involves investigators throughout North America.

The overall goal of the program is to understand the biologic mechanisms underlying the results of the PCPT. These ancillary studies will analyze the prostate tissue, blood and white cell samples collected during PCPT. The unifying theme is the genetic, metabolic and environmental factors associated with the risks of prostate cancer and high-grade prostate cancer, as well as the effects of these factors on how effective finasteride is in preventing prostate cancer.