Prostate Drug Finasteride Can Safely Lower Cancer Risk, Study Says

In continuation of my update on Finasteride

Finasteride, best known as the enlarged-prostate medicine Proscar, is a safe, effective way to reduce the risk of prostate cancer, according to long-term findings from the Prostate Cancer Prevention Trial (PCPT).

The trial was funded by the U.S. National Cancer Institute and enrolled nearly 19,000 men between 1993 and 1997.

Initially it found that finasteride -- a hormone-blocking drug -- cut the risk of prostate cancer by 25 percent. Those results were published in 2003.

The newly released long-term data show that the reduction of prostate cancer risk has continued and that fewer than 100 men in the trial died from prostate cancer in more than two decades of follow-up, according to a research team led by Dr. Ian Thompson.

The updated results also showed no statistically significant increased risk of death from prostate cancer among men taking finasteride. This removes concerns over early findings of a possible risk of more aggressive cancers among patients who take the drug.

"Finasteride is safe, inexpensive and effective as a preventive strategy for prostate cancer," said Thompson, who is principal investigator of the PCPT for the SWOG Cancer Research Network.

The SWOG Cancer Research Network is an international cancer clinical trials group.

"Doctors should share these results with men who get regular prostate-specific antigen [PSA] tests that screen for the presence of prostate cancer," Thompson said in a SWOG news release. "The drug will have its greatest effect in this group of men."

Thompson is also emeritus professor at the University of Texas Health Science Center. He and his team published their findings Jan. 23 in the New England Journal of Medicine.

A cheap, reliable prostate cancer prevention drug will have a big impact on public health, Thompson and his colleagues said.

They noted that prostate cancer rates are on the rise and that nearly 165,000 American men were diagnosed with the cancer in 2018, according to the American Cancer Society.

Many cases of prostate cancer are slow-growing and not life-threatening, but are still often treated with surgery and radiation, sometimes resulting in complications such as impotence and incontinence.

"There are significant negative consequences to patients' health and quality of life that can result from prostate cancer treatment, as well as to their finances and their peace of mind," Thompson said.

"If we can save people from surgeries and scores of examinations and tests, and spare them from living for years with fear, we should. The best-case scenario for patients is prevention, and this trial has found an inexpensive medication that gets us there," he concluded.

One prostate specialist unconnected to the research said the new findings come after "many years of debate" on finasteride's role in cancer prevention.

Based on early findings from the PCPT, the U.S. Food and Drug Administration "issued a warning that chronic use of the medication may increase the risk of high-grade or aggressive prostate cancer in a small percentage of men," said Dr. Manish Vira. He helps direct urologic research at Northwell Health's Arthur Smith Institute for Urology in Lake Success, N.Y.

Unfortunately, that warning "effectively nullified the benefits of the medication in the eyes of many patients and their physicians," Vira said.

These later, fuller results should turn that around, he noted.

"Physicians and patients need to be aware of these results, and at least consider again using these medications in the prevention of prostate cancer," Vira said."This may be especially true among men at high risk, such as African-American men and men with a strong family history of prostate cancer," he said.

https://en.wikipedia.org/wiki/Finasteride

https://www.webmd.com/drugs/2/drug-1548-167/finasteride-oral/finasteride-oral/details

Prostate Drug Finasteride Can Safely Lower Cancer Risk, Study Says 

Finasteride does not increase risk of prostate cancer death

Twenty five years after it opened for enrollment, the landmark Prostate Cancer Prevention Trial has delivered a final verdict. Finasteride, a common hormone-blocking drug, reduces mens' risk of getting prostate cancer without increasing their risk of dying from the disease. Initial study findings suggested there may be a link between use of the drug and a more lethal form of prostate cancer, but long-term follow-up shows that is not true.

Dr. Ian Thompson, Jr., principal investigator of SWOG's Prostate Cancer Prevention Trial, or PCPT, will deliver the findings May 19 at the Journal of Urology Lecture at the 2018 Annual American Urological Association Meeting in San Francisco. The meeting is the largest gathering of urologists in the world.

"What we can now say is that finasteride not only significantly reduces a man's risk of prostate cancer, it is safe to use based on very long-term follow-up in our study," said Thompson. "In PCPT, we found no increased risk of prostate cancer death in men who took finasteride compared with men who did not. These results are transformational. Prostate cancer is the most common cancer diagnosed in American men, and we have found an inexpensive, effective drug that can prevent it. I'm pleased to report that we've answered the questions and closed the book."

Thompson is chair of SWOG's genitourinary cancer committee, overseeing development of all urologic cancer studies for the federally-funded cancer clinical trials group, and serves as president of CHRISTUS Santa Rosa Hospital—Medical Center in San Antonio, Texas and as emeritus professor at the University of Texas Health Science Center. Thompson led SWOG's landmark PCPT. He and his team set out to determine whether finasteride, a drug used to treat symptoms of prostate enlargement as well as male pattern baldness, would prevent prostate cancer in men over the age of 55. At the time, scientists and doctors knew that prostate cancers were hormonally sensitive, and finasteride, the first 5-alpha-reductase inhibitor, which targets and blocks the action of androgens like testosterone, became available to test.

The PCPT randomized 18,882 men from 1993 to 1997 to finasteride or a placebo—making it one of the largest cancer prevention trials ever mounted. The trial intervention was stopped in 2003 when investigators found a significant, positive result: finasteride reduced prostate cancer risk by 25 percent. But the study also showed that finasteride produced a small increase in the number of high-grade prostate cancers—a negative finding that resulted in a "black box" warning posted by the U.S. Food and Drug Administration on prescription drug labels to flag potentially disabling or life-threatening side effects.

Subsequent SWOG analyses of PCPT data revealed unexpected benefits of finasteride. It improved detection of prostate cancer in screening tests and biopsies, and also improved detection of high-grade cancers. Additional analysis also revealed that men enrolled in the study lived about the same amount of time—regardless of whether they took finasteride or the placebo. Still, despite evidence of the benefits of finasteride, the label warning had an impact. Few men today take the generic drug to lower their cancer risk.

As most deaths from prostate cancer are caused by high-grade cancers, years of PCPT findings still left a critical question unanswered: Would the increased number of high-grade cancers detected in the PCPT years ago result in more prostate cancer deaths over time?

Thompson and his team went back to the study and matched participants to the National Death Index, a centralized database of death record information managed by the U.S. Centers for Disease Control and Prevention. This analysis allowed researchers to determine if a trial participant had died and to determine the cause of death. With almost 300,000 person-years of follow-up and a median follow-up of 18.4 years, they found 42 deaths due to prostate cancer on the finasteride arm and 56 on placebo. Thus, there was no statistically significant increased risk of prostate cancer death with finasteride.

"This discovery could benefit tens of thousands of men each year in the United States by identifying a drug that can safely and effectively prevent prostate cancer," Thompson said. "Treatment for the disease is costly and can have serious side effects, such as impotence and urinary incontinence. My hope is that the visionary decision of our National Cancer Institute colleagues to conduct this study, and the scientific evidence it produced these last 25 years, will provide a lasting benefit for patients."