Two decades ago, targeting tumors with highly potent doses of radiation involved a technique reserved for the brain, where doctors could use a halo to stabilize the organ and ensure accuracy. But starting in the late 1990s, slow-rolling progress brought that therapy to the body, where radiation had traditionally been delivered with lower potency and over a longer period of time. A Dallas physician has played a key role in facilitating the evolution.
Dr. Robert Timmerman, a professor of radiation oncology and neurological surgery with UT Southwestern Medical Center, was one of the first researchers in the world to bring the specialized treatment techniques, previously only used on the brain, to tumors located within the body. Today, use of stereotactic ablative radiotherapy, or SABR, is on the rise thanks both to its convenience factor and to research that has shown its effectiveness.
With SABR, advanced imaging technology and sophisticated planning software allow extremely potent doses of radiation to be delivered from multiple angles. Whereas standard radiation would be delivered five days a week over the course about two months, SABR treatment takes place over one to five treatments.
Timmerman has served as the lead investigator in several national trials designed to evaluate SABR’s efficacy and safety. In one highly cited study of treatment for inoperable lung cancer published in 2010 by the Journal of the American Medical Association, Timmerman’s team found that SABR offered a 3-year tumor control rate of 97.6 percent, versus the typical control rates of 30 to 40 percent for patients receiving standard radiation treatments.
Timmerman has had a hand in trials that have applied SABR to treat cancer in the liver, spine, and prostate. Although prostate cancer patients who find the disease early are relatively low-risk, Timmerman says SABR can offer a more convenient treatment option. It could also prove to be a better treatment for high-risk patients, he says.
It’s the results of a comparison trial, however, that Timmerman says holds the most promise in boosting physician belief and bringing SABR to a wider base of patients. For the trial, early-stage lung cancer patients are randomly assigned either SABR or surgery to remove the tumor. Timmerman said he expects they’ll get the 270 patients they need within the next couple of years; 82 have enrolled so far.
“Even if the treatment doesn’t win the comparison, it looks like it will compete well with it—and the bottom line for patients is that they’ll have the luxury of more options,” Timmerman says.