Nearly every state with legalized medical marijuana allows cancer patients to obtain a prescription for the drug. But just how many actually take advantage of it? Well, it might be less than you think.

The Fred Hutchinson Cancer Research Center recently surveyed over 900 patients at the Seattle Cancer Center Alliance and asked them about using marijuana during their treatment. According to their results, 24 percent of patients said they'd used marijuana in the past year, and 21 percent said they'd done so in the past month.

Considering Washington has completely legalized cannabis, you might think these results would be higher since patients wouldn't need to go through the process of obtaining a prescription. And the numbers are low when compared with how many patients are interested in using medical marijuana. According to the same survey, 74 percent of cancer patients said they were interested in more information about marijuana from their doctors.

Studies have shown that marijuana is effective at treating the side effects of chemotherapy, such as nausea, pain and loss of appetite. There are also preliminary studies where THC and other cannabinoids have either slowed the growth or even killed certain types of cancer cells in lab dishes. These studies are still in the early stages, and there isn't a wealth of information about how marijuana can help treat cancer, but they are encouraging signs.

Unfortunately the federal government's classification of marijuana as a Schedule I narcotic prevents much of the research into the possible medicinal effects of the drug. But at some point the research will be so insurmountable that the federal government will have to change their ways.