Medicare claims show long-term prostate cancer prevention benefits of finasteride

March 20, 2018, SWOG

Men who take the medication finasteride get a prostate cancer prevention benefit that can last 16 years - twice as long as previously recorded, according to SWOG clinical trial analysis published in the Journal of the National Cancer Institute.

This finding was made possible by a new research strategy - linking Medicare claims data to , in this case from a landmark study run by SWOG, the federally funded cancer clinical trial network. The SWOG study, known as the Prostate Cancer Prevention Trial, or PCPT, set out to see whether finasteride, a drug used to treat symptoms of enlargement as well as male pattern baldness, would prevent in men over the age of 55. The study enrolled 18,882 men from 1993-1997. It was stopped in 2003 when investigators learned that finasteride reduced by 25 percent when compared with a placebo. SWOG leader Ian Thompson, Jr., MD, of CHRISTUS Santa Rosa Hospital Health System, was the study chair of PCPT.

Joseph Unger, PhD, a SWOG biostatistician and health services researcher from Fred Hutchinson Cancer Research Center, has a track record of using new research methods to answer bigger, bolder questions about cancer prevention and treatment. Along with SWOG colleague Dr. Dawn Hershman, Unger has pioneered for a decade the use of secondary sources of data, such as Medicare claims, U.S. Census Bureau data, and public health statistics from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program, to examine new hypotheses.

For this study, Unger wanted to know if the protective effects of finasteride lasted longer than seven years - the amount of follow-up evaluated in the PCPT. Answering this question would typically require reopening the old study, reconnecting with patients, and conducting extensive follow-up - an expensive and time-consuming proposition. But Unger took another tack, requesting and obtaining a data use agreement from the federal Centers for Medicare & Medicaid Services to access to records from Medicare, the health insurance program for people over 65.

Using patient information from the PCPT, Unger linked patients enrolled in the PCPT to their Medicare claims from 1999 through 2011. The team was surprised to find they were able to successfully link 75 percent of PCPT trial participants. Unger and colleagues at Fred Hutch created an algorithm to flag a prostate cancer diagnosis in the Medicare data, and examined the diagnoses over time. The team identified 3,244 PCPT participants who were later diagnosed with prostate cancer over a median follow-up of 16 years, and found that participants on the PCPT that took finasteride had a 21 percent decreased risk of getting prostate cancer, compared to those who took a placebo drug, over the course of those 16 years.

"These findings raise the intriguing possibility that seven years of can reduce prostate cancer diagnoses over a much longer period than was previously shown," Unger said. "It's a low-cost generic drug, with minimal side effects, that can have a benefit that lasts long after men stop taking it."

At the same time, Unger said, the SWOG study shows the value of using Medicare claims to extend follow-up for trial participants and answer new questions about cancer care and prevention. "These secondary data sources are emerging as a new paradigm for long-term follow up for clinical ," he said. "It's an exciting new avenue of research."

Explore further: Risk factors for prostate cancer aren't what we think, study shows

More information: The National Cancer Institute and the National Institutes of Health funded the study through grants UG1CA189974, UM1CA182883, and U10CA37429.

Related Stories

Risk factors for prostate cancer aren't what we think, study shows

October 31, 2016
When it comes to prostate cancer biopsies, risk and reality don't always match up, according to research published online today in the Journal of Clinical Oncology.

Finasteride saves men from prostate cancer, doesn't increase risk of death

August 14, 2013
A long-term follow-up to a groundbreaking study led by the director of the Cancer Therapy & Research Center confirms that a drug shown to reduce risk of prostate cancer by more than a third has no impact on lifespan but further ...

Effect of treatment trials on survival of patients with cancer in US population

June 6, 2017
Joseph M. Unger, Ph.D., M.S., of the SWOG Statistical Center and the Fred Hutchinson Cancer Research Center, Seattle, Wash., and coauthors examined how the National Cancer Institute-sponsored network of cooperative cancer ...

Negative cancer trials: Short-term whimper, long-term bang

March 10, 2016
Cancer clinical trials with negative results don't make an immediate splash in the scientific literature, but they do have a long-term impact on cancer research, according to a new study by SWOG, the federally funded international ...

Recommended for you

Dying cancer cells make remaining glioblastoma cells more aggressive and therapy-resistant

June 21, 2018
A surprising form of cell-to-cell communication in glioblastoma promotes global changes in recipient cells, including aggressiveness, motility, and resistance to radiation or chemotherapy.

Existing treatment could be used for common 'untreatable' form of lung cancer

June 21, 2018
A cancer treatment already approved for use in certain types of cancer has been found to block cell growth in a common form of lung cancer for which there is currently no specific treatment available.

Novel therapy makes oxidative stress deadly to cancer

June 21, 2018
Oxidative stress can help tumors thrive, but one way novel cancer treatments work is by pushing levels to the point where it instead helps them die, scientists report.

Researchers uncover new target to stop cancer growth

June 21, 2018
Researchers at the University of Wisconsin-Madison have discovered that a protein called Munc13-4 helps cancer cells secrete large numbers of exosomes—tiny, membrane-bound packages containing proteins and RNAs that stimulate ...

Higher body fat linked to lower breast cancer risk in younger women

June 21, 2018
While obesity has been shown to increase breast cancer risk in postmenopausal women, a large-scale study co-led by a University of North Carolina Lineberger Comprehensive Cancer Center researcher found the opposite is true ...

New treatment helps avoid deafness in child chemotherapy patients

June 21, 2018
An international trial has found that a medicine commonly used to treat poisoning is effective in reducing deafness in children receiving chemotherapy for cancer.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.