In the first study, researchers found that most men are getting their prostate removed or undergoing radiation therapy when carefully watching the cancer may be just as effective without the risks and side effects of surgery or radiation.
"The variation of treatment of low-risk prostate cancer by physicians was striking," said lead researcher Dr. Karen Hoffman, an assistant professor at the University of Texas MD Anderson Cancer Center in Houston.
Hoffman added that the doctor who diagnoses the cancer has the biggest influence on what treatment the patient will choose.
"The diagnosing urologist influences a man's treatment fate. The urologist not only influences up-front treatment versus observation, but also the type of treatment," she said.
Hoffman found that doctors who were older were more likely to recommend surgery or radiation rather than observation. Moreover, men were more likely to have surgery or radiation therapy if their urologist did that procedure, she added.
The rate of observation as opposed to other treatments across urologists ranged from almost 5 percent to 64 percent of patients. For men diagnosed by radiation oncologists, the rate of observation also varied from 2 percent to 47 percent, Hoffman said.
There may be a financial incentive at work here, said Dr. Anthony D'Amico, chief of radiation oncology at Brigham and Women's Hospital in Boston. He was not involved in the study.
"You make a diagnosis and there is a financial incentive in keeping the patient," he said. However, the urologist may also believe in treating the patient rather than choosing observation, he said.
D'Amico advises that any man diagnosed with prostate cancer get a second opinion. "With prostate cancer, there are options for treatment and sometimes surveillance is the right thing to do. So, men really need to get a second opinion in conjunction with their primary care physician, who knows their overall health and their wishes," he said.
He noted that side effects of surgery or radiation include impotence, incontinence and rectal bleeding. "So, you should not just go with the first person who diagnoses you," D'Amico said.
For the study, Hoffman's team collected data on a little more than 2,000 men, aged 66 and older, diagnosed with low-risk prostate cancer from 2006 through 2009. The diagnosis was made by urologists, the researchers noted. Among these men, 80 percent received treatment and 20 percent were observed.
In the second report, a team led by Dr. Grace Lu-Yao, a professor of medicine at the Rutgers Cancer Institute of New Jersey and Robert Wood Johnson Medical School in New Brunswick, N.J., found that hormone treatment did not improve survival in men with prostate cancer that had not spread beyond the prostate.
"The data do not support the practice of using hormone therapy as the sole therapy for elderly patients with localized prostate cancer," Lu-Yao said.
Because hormone therapy is associated with side effects such as osteoporosis, diabetes and decreased muscle tone, doctors must carefully consider the reasons for using this treatment as the primary treatment for older men with low-risk localized prostate cancer, she said.
Using federal government data, Lu-Yao's team collected information on almost 67,000 Medicare patients, diagnosed between 1992 and 2009. These men had not had surgery or radiation within 180 days of diagnosis, the researchers said.
During an average of 110 months of follow-up, hormone therapy was not associated with improved survival, the researchers found.
In fact, 15-year survival in men, whether their cancer was fast- or slow-growing, didn't differ if they received hormone therapy or not, the researchers found.
Survival among men with slow-growing cancer was about 90 percent with or without hormone therapy. For men with fast-growing cancer, survival was about 78 percent among both men treated with hormone therapy and men who weren't.
Both studies were published online July 14 in the journal JAMA Internal Medicine.
Visit the American Cancer Society for more on prostate cancer.