When John Ray was diagnosed with lung cancer last year, he faced a difficult decision.
He had to choose between a standard chemotherapy drug or enroll in a clinical trial testing two other promising treatments.
"The standard treatment has had good success, and I just didn't want to risk not being able to have that," Ray said.
His situation is emblematic of a major issue in cancer treatment.
There are more than 400 cancer drugs now in clinical trials, many of which are experimental medicines with the potential to treat some of the most lethal and common forms of cancer.
The only problem is that researchers are running out of cancer patients to test all these new drugs on.
"Only about 3 percent of cancer patients participate in cancer clinical trials," said Dr. Robert Comis, a clinical trial expert and board president of the Coalition of Cancer Cooperative Groups.
Three percent is not nearly enough to test the expanding number of cancer drugs now in development, Comis said.
"There's no question that with the low level of participation, clinical trials take longer and the newer, more effective treatments take longer to become available to the overall public at large," he said.
For the cancer patient, waiting for that new drug may come too late.
"It may be the difference between surviving and not surviving," said Dr. Robert Pluenneke at the Kansas City Cancer Center.
So why aren't more patients enrolling in clinical trials?
"For some people, it's a matter of risk. Other people, it's a matter of convenience. Some trials require the person to return for additional testing," said Dr. Gary Hudes of the Fox Chase Cancer Center.
Surprisingly, the most common reason patients don't enroll is that they don't know they can.
The Coalition of Cancer Cooperative Groups did a recent survey and found that only 10 percent of cancer survivors knew of any clinical trial for their specific cancer.
So, increasingly, researchers are encouraging patients to do their homework on new drugs.
The National Cancer Institute's Web site, for example, has extensive lists of clinical trials sorted by the type of cancer and even the ZIP codes of the nearest trials.
"If there is a new treatment that works and if you don't take your chances, you can't win. But again, it still represents some element of risk," Hudes said.
Usually a small element, researchers said.
Studies show that cancer patients in clinical trials generally do as well or better than patients who do not enroll.