Nearly 50 years after the United States declared war on cancer, the University of Minnesota is launching research into one of the chief casualties — men who survived their diseases only to encounter a lifetime of side effects from aggressive and even toxic treatments.

Male death rates from prostate and testicular cancers have been halved since 1995 because of advances in radiation, chemo­therapy and drugs that suppress cancer-fueling hormones such as testosterone. But the treatments take a toll, said Dr. Charles Ryan, a U prostate cancer specialist. Reducing testosterone alone can affect men's mood, strength and energy.

"We're doing to men what menopause does to women," said Ryan, who is a leader in the field known as cancer survivorship. "The concept is looking at what happens to the bodies and the brains and the minds and the muscles of these men."

The U has become a national leader in pediatric cancer survivorship by closely tracking the health of men and women who were treated in childhood for leukemia and other cancers. Now, it's expanding its focus to include adult male cancers with the recruitment of Ryan as the U's director of hematology, oncology and transplantation, and the receipt of philanthropic support from a cancer survivor.

Twin Cities businessman Scott Petinga, who suffered prolonged side effects after treatment for testicular cancer, recently announced a $500,000 gift to the U and Ryan to advance the research. Petinga's treatment included hormone deprivation, and he later suffered a variety of problems — from infertility to nerve pain to brittle bones to muscle atrophy. Now he fears the hormone disruption is interfering with his memory.

"You start to forget words," said Petinga, 45, a father of three grade-school-aged daughters. "You forget sometimes where you're going, or how to get home."

The research linking cancer treatment with memory loss or dementia is thin, but Ryan said the U will explore the connection. Petinga's donation will support studies to identify which patients have genetic or neurological traits that put them at greater risk for treatment side effects, and which can beat their cancers with less aggressive therapies.

"If we can identify risk factors, people may be able to benefit from less therapy rather than more," Ryan said.

Petinga said he believes his side effects were caused by overtreatment a decade ago of an early-stage cancer. His doctor recommended aggressive use of hormones and radiation, Petinga said, and was focused on his five-year survival, a common target in cancer medicine.

"No one [cares] what happens after five years and a day," Petinga said. "Everybody washes their hands because they did what they were supposed to do."

Improved cancer survival rates are a success story in American medicine. Relative five-year survival is now 98 percent for men with prostate cancer and 95 percent for testicular cancer, according to a 2019 American Cancer Society report. The rate of prostate cancer deaths has dropped to a level not seen since the 1930s, and well below the rate in 1971 when President Richard Nixon signed research legislation that was deemed to be a war on cancer.

The challenge for doctors now is to tailor care to prevent overtreatment, and to better prepare patients for life after cancer, without sacrificing the survival rate, Ryan said.

The American College of Surgeons at the start of 2019 required cancer centers to offer survivorship planning to at least half of eligible patients as a condition of accreditation.

When Dr. Anne Blaes arrived at the U in 2009, she started an adult cancer survivorship program to complement existing supports for pediatric cases.

Patients now receive post-treatment care plans that warn them about long-term side effects and connect them with community programs such as Livestrong's partnership with the YMCA to help cancer survivors stay fit.

Some strategies for survivors are already known. Hormone suppression can increase the risk of diabetes, for example, so patients need to eat well and exercise after cancer care.

Blaes said insurers could help by covering cancer rehabilitation in the same way that they cover post-treatment therapy for cardiac patients.

Still, she said, scientists need to know more about how cancer treatments, especially new immunologic therapies, affect the body over time.

"There's a lot that we don't know about the genetics of why one person can go through this treatment and run a marathon and another person can't."

The aftereffects of hormone deprivation can vary based on how and when it is used. Doctors might order hormone therapies right away in combination with radiation, or wait to try to prevent tumors from re-emerging. Some patients continue taking drugs to suppress hormones after cancer remission. Others stop taking the drugs, but their hormone levels don't return naturally, Ryan said.

Petinga has taken his post-cancer treatment in a direction that some doctors discouraged. Instead of suppressing hormones to prevent cancer from returning, Petinga said he receives hormone implants every eight to 10 weeks to restore his energy and mood. While recognizing the cancer risk, Petinga said there is evidence that their absence contributes to cognitive problems.

Financial resources have helped him make his own medical choices. The entrepreneur founded a big data marketing firm and later launched a variety of specialty retailers. He also created the nonprofit group Cacti to inform men about options for treating testicular cancer, and Think Different to support creative solutions to shortages of low-income housing and health care.

The Minnetonka man said he is fearful of losing his cognition and not being able to participate in his daughters' future as they reach life milestones.

"I want to be able to remember it and partake in it," he said.

In addition to the U donation, Petinga recently gave $600,000 to the University of Southern California to study the most effective methods for treating early-stage testicular cancer while preventing side effects over time.

With the population of American cancer survivors expected to grow in the next five years, from 15 million to more than 18 million, survivorship research will be more and more urgent, Ryan said.

"That's an incredible number of people who are alive today."