Tracy has agricultural roots and affordable homes, but a new study reveals a less obvious distinction for this Central Valley city: Doctors use internal radiation to treat men for prostate cancer at the highest rate in California, more than four times the state average.
By comparison, men living just 60 miles away near Stanford University are much less likely to undergo the procedure known as brachytherapy, or radiation seeds -- only about half as often as the state average.
Geographic differences also exist in treatments for early-stage breast cancer, the study found. Livermore women are 92 percent more likely than the state average to have a lumpectomy without radiation. But across the bay in San Mateo, women are much more likely to have a lumpectomy with radiation.
These and other sharp variations in treatments, based on where patients live, are detailed in a study released Tuesday by the California HealthCare Foundation.
The huge differences indicate that doctors often determine which treatments will be used -- more than patients or even medical science, researchers say.
In a small community such as Tracy, one doctor or medical group that promotes brachytherapy can have a big impact on the care residents receive, said Maribeth Shannon, director of the market and policy monitor program for the foundation, a nonprofit group in Oakland that seeks to improve health care for the state's residents.
"You've got to wonder if all the (Tracy) men realize what their options are," she said.
If patients played a bigger role in the decision-making, there would be less difference from one community to the next, Shannon said.
"Physicians, for whatever reason, get comfortable with a particular treatment," she said. "There's not as much true shared decision-making as there should be."
Earlier studies have used Medicare records and found similar variations in treatment based on where people live. This latest study also included data from commercial plans, Medi-Cal and the uninsured from 2005 to 2010.
An interactive map with statistics on a host of different conditions can be viewed at www.chcf.org/variations.
The researchers hope doctors and community members will use the information to re-examine how they do things if they are far from the norm, Shannon said.
Medical experts disagree about how often men should undergo PSA screening tests for prostate cancer and how they should be treated if cancer is diagnosed. Some believe that if the cancer is small and slow-growing, patients should simply be closely monitored. Others favor more aggressive treatments.
"There's no strong evidence to suggest one (treatment) is better than the other," said Dr. Benjamin Chung, an assistant professor of urology at Stanford University.
Oncologists at Stanford tend to use external beam radiation more than brachytherapy to kill cancer cells, Chung said. This often involves the use of expensive equipment to target the tumor while attempting to minimize damage to surrounding tissues.
Men need to be well-informed about their options and the possible side-effects, and doctors need more research on the outcomes of various treatments, said Dr. Matthew Cooperberg, an assistant professor in the departments of urology and epidemiology and biostatistics at UC San Francisco.
"There are very different financial incentives for one treatment over another," noted Cooperberg, who served on the advisory committee for the study.
George Swartz, who heads USTOO, a support group for men who have prostate cancer that meets in San Ramon, said he opted for brachytherapy when he was diagnosed 13 years ago after his physician explained the options. But he added that too often, doctors simply recommend a treatment without finding out what the patient desires.
"Physicians behave in a way that's very paternalistic," Swartz said.
Even though she does not have breast cancer, actress Angelina Jolie drew attention to breast cancer options last week when she opted for a double mastectomy after learning she has a genetic mutation that increases her risk.
The study found varying rates of mastectomies for early-stage breast cancer from one community to the next. Women in the Vacaville area were more likely to have a single mastectomy than the average California woman, while women in San Ramon were more likely to have a double mastectomy than the average.
Shannon noted that doctors may recommend treatments based on what was popular at the time they received their medical training. She suggested that physicians provide patients with decision-making tools to help them weigh the medical evidence and the trade-offs involved in each choice.
Patients then need to do their part. "Engage -- tell the doctor what you think," she said.
Sandy Kleffman covers health. Contact her at 510-293-2478. Follow her at Twitter.com/skleffman. ___