Calypso Study Shows Pinpoint Radiation for Prostate Cancer Curbs Side Effects
Calypso Medical Technologies was founded a decade ago on the belief that it could reduce side effects for cancer patients getting radiation treatment. Now the Seattle-based company has the first batch of clinical trial data to prove it.
A study of 64 patients who used the Calypso system to track their prostate tumors in real-time during radiation sessions had fewer bowel-related side effects like diarrhea, as well as less urinary irritation and erectile dysfunction, researchers said this week in the journal Urology. The findings were stacked up against those from a study published two years ago in the New England Journal of Medicine that enrolled 153 similar patients who got standard radiation, without the real-time, prostate tracking feature offered by Calypso.
The Calypso system works by implanting tiny transponders in the cancerous prostate gland, which sends a signal to a base station which tracks the precise 3-D location of the prostate in real-time. By offering more precise, real-time tracking, doctors can keep the beams of radiation aimed exclusively at the cancerous target, without harming healthy bladder and rectal tissue nearby. If a patient burps or twitches on the treatment table, technicians can see immediately if the beams are off track. The more precise targeting enables doctors to use high-intensity, more narrowly focused radiation beams that could ultimately save the patient from being impotent or having to wear adult diapers the rest of their lives.
Calypso’s system was first cleared for sale in the U.S. in July 2006, based on some simple studies that showed it was safe, and roughly comparable in terms of accuracy to predecessor X-ray systems. But that didn’t really offer proof that it helps patients lead healthier lives. That’s a key question Medicare wants to see answered, as the Calypso system can cost $400,000 to $500,000 for the machine, plus $1,200 per patient for implantable transponders. Essentially, the new clinical trial data is important because it’s the first evidence that says Calypso’s technology can do what it’s supposed to do for patients.
“Radiation therapy has been getting better and better throughout my career, but this really represents an additional improvement in quality of life for patients getting radiation therapy today, even when compared to just a couple years ago,” says Howard Sandler, the chair of radiation oncology at Cedars-Sinai Medical Center in Los Angeles, and the lead author of the study published in Urology.
The results were based on questionnaires the patients filled out about their quality of life two months after they completed a typical eight-week course of radiation. On a scale of 0 to 100, patients said their bowel function was rated at about 90.3 when they started the radiation treatment with the Calypso system, and 88.8 after they completed therapy—which basically means patients weren’t harmed, Sandler says. By contrast, the patients in the comparison study, who got standard radiation, saw their quality of life scores on bowel function drop by 16 points on the 100-point scale. That’s a big enough difference that Sandler says he would now advise patients not to worry about their bowel control as much if they use the Calypso system.
Of course, the study doesn’t answer every important question … Next Page »