Avodart (dutasteride) used to treat benign prostatic hyperplasia (BPH) may slow the growth of early-stage prostate cancer

A recent study presented on Feb. 17-19th  at the 2011 Genitourinary Cancers Symposium in Orlando, FL by researchers from the University Health Network in Toronto, Canada concluded that for men who are undergoing “watchful-waiting” for prostate cancer, Avodart could help control the disease and prevent the need for more aggressive treatments. “Watchful waiting,” or active-surveillance refers to the practice of foregoing immediate treatment after a prostate cancer diagnosis in favor of regularly-scheduled testing and clinical exams to closely monitor the disease.

Avodart (dutasteride) is already approved by the Food and Drug Administration (FDA) for the treatment of an enlarged prostate gland, or benign prostatic hyperplasia (BPH). The drug inhibits an enzyme called 5-alpha reductase, which converts testosterone into its more potent form, dihydrotestosterone. In addition to BPH, 5-alpha reductase drugs are also used to treat prostate cancer and baldness. Further details from the study can be found in the Feb. 22, 2011 issue of the National Cancer Institute (NCI) Cancer Bulletin. ”In the dutasteride group, 38 percent of the 302 men enrolled in the study experienced some progression of their cancer, compared with 49 percent of the men in the placebo (control) group. This difference translated into a reduction of relative risk for cancer progression of 38.9 percent in the dutasteride group. In addition, taking dutasteride increased the chances that no cancer would be found during a participant’s final biopsy. Thirty-six percent of the men in the dutasteride group and 23 percent of the men in the placebo group had no cancer detected in their final biopsy specimens.” The researchers suggested that it could be “very reasonable” to give a 5-alpha reductase inhibitor such as dutasteride to patients with “ultra low-risk” prostate cancer who elect for “watchful waiting”. It was also noted that the FDA’s Oncologic Drugs Advisory Committee had previously rejected GlaxoSmithKline’s application for dutasteride for use in preventing prostate cancer.

A word of caution regarding the Avodart study described above was recently published on March 9th in the Johns Hopkins Health Alerts: Prostate Disorders. The Hopkins physicians stated that it was unclear whether Avodart actually prevents prostate tumors or simply reduces the chance of a diagnosis. They noted that in the above study, “more people in the placebo group than in the Avodart group received a diagnosis of prostate cancer during the four-year study: 25% versus 20%.  While these findings may sound like good news, it’s possible that Avodart simply suppressed PSA levels, rather than preventing the development of new cancers. Another concern: More men in the Avodart group than in the placebo group were diagnosed with a tumor with a high Gleason score — the tumors most likely to be lethal. ” The Johns Hopkins physicians advised that “if you take Avodart for any reason, be sure that the doctor who performs your PSA screening test is aware of this information. Because Avodart may simply be suppressing your PSA level, he or she will need to perform a mathematical calculation to determine your “true” level. “