Simonton, who founded a cancer-care clinic in Pacific Palisades in the early 1980s, choked to death June 18 during a meal at his Agoura Hills home, said his wife, Karen.
Early in his medical career, Simonton noticed that patients given the same dose of radiation for similar cancers had different outcomes. When he looked into why, he concluded that people who had a more positive attitude generally lived longer and had fewer side effects.
Talking openly about cancer was groundbreaking in the 1970s, as were such Simonton techniques as meditation and mental imagery, said Julia Rowland, director of the National Cancer Institute's Office of Cancer Survivorship.
"For an oncologist to pioneer a mind-body approach was very provocative at the time, and yet very humane," Rowland said. "It gave people more of a sense of control over their illness and allowed patients to think differently about their role in the healing process."
After implementing an early psychosocial oncology program while chief of radiation therapy at Travis Air Force Base in Fairfield, Calif., in the early 1970s, Simonton founded a cancer counseling and research center in Fort Worth that included emotional support as a key component.
His own research indicated that when lifestyle counseling was added to medical treatment for patients with advanced cancer, their survival time doubled and their quality of life improved.
A study by Stanford University and UC Berkeley researchers in 1989 concluded that women with advanced breast cancer who received emotional counseling lived about twice as long as those who did not.
The study was independent evidence that Simonton's "whole-body" approach to battling the illness made a difference, Dr. David Siegel, a psychiatrist and Stanford professor who wrote the study, wrote in an e-mail to The Times.
Simonton outlined his "will-to-live" philosophy of cancer care in "Getting Well Again," a 1978 book written with his second wife, a psychotherapist then known as Stephanie Matthews-Simonton, and others. It drew on firsthand experience with patients at his Fort Worth cancer-care center.
The book was "highly praised" by officials at the National Institutes of Health and doctors who specialized in cancer and heart problems, The Times reported in a 1981 article with the headline, "Medicine's 'Other Side' -- the Mind."
Thousands of counselors have been trained in the Simonton Method, which includes teaching patients to visualize their bodies fighting cancer cells -- and winning the war.
According to the American Cancer Society, "available scientific evidence does not support claims that imagery can influence the development or progress of cancer" but it can help reduce stress, depression, manage pain and ease side effects, in addition to creating "feelings of being in control."
The use of guided imagery is much more accepted and widely used today, especially to manage side effects, a development that can be traced to Simonton's research, said Rowland of the National Cancer Institute.
Differences over theory caused his divorce from Matthews-Simonton, who went on to establish a more psychologically oriented clinic in Arkansas. Simonton's first marriage also ended in divorce.
In 1984, he was seeking a professional climate that would be friendlier to his controversial work when he founded the Simonton Cancer Counseling Center in Pacific Palisades. The center will continue operating.
He insisted that feelings of hopelessness contribute to a hastier death.
"Most of us kill ourselves with unconscious emotional pain," he said in a 1995 interview and warned to beware of those who say there is no hope.
"Label those people as ill- informed and hazardous to your health," he said.
Oscar Carl Simonton was born at home in West Los Angeles on June 29, 1942.
He was the youngest of four children of a Baptist minister and his wife.
After undergraduate work at an Arizona college, Simonton earned his medical degree at the University of Oregon.
In his late 30s, Simonton was described as having "a penchant for four-letter expletives and a willingness to appear on a platform in his jogging shorts" to give a speech.
Laughing, his wife Karen said that remained an apt description of her husband, who loved to crack jokes and thought nothing of accidentally wearing tennis attire to a formal dinner.
In addition to his wife of 27 years, Simonton is survived by their children, Chase and Elizabeth; two daughters from his first marriage, Sheryl Herrera and Shannon Balster; and three sisters, Patricia Norman, Anne Glenny and Jean Bradley.
A memorial is being planned.
Instead of flowers, the family suggests donations to the Simonton Cancer Center Scholarship Fund, used for patients with financial need, P.O. Box 6607, Malibu, CA 90264.