Over 200 years ago, a surgeon in New York City, named Dr. William Coley, discovered that he could fight the tumors of cancer patients by injecting them with live Streptococcus bacteria. After some trial and error, he switched to using dead bacteria, and ultimately treated over 1000 patients with what were eventually dubbed “Coley toxins.” The advent of current cancer treatments such as radiation, chemotherapy and surgery pushed Coley’s methods into the background. Interestingly, though, it was discovered in 1999 that his success rates were similar to those for modern cancer therapies.
For over a decade, Bert Vogelstein, a cancer geneticist at Johns Hopkins University in Baltimore, Maryland, has been using the soil-dweller bacterium, Clostridium novyi. This bacterium thrives in areas of low oxygen, which is typical of tumors. While initial results were promising in rats, the researchers then extended the study to 16 pet dogs, and found that the tumors shrank or disappeared in six of the dogs, and stopped growing in another five dogs. Several of the dogs needed surgery to clear the wounds when the tumors disintegrated. Following the canine study, a safety trial was performed on one person. More details on the study can be found here.
In addition to destroying tumor cells, the bacteria also spur immune cells in the body to attack the cancer. The biggest concern associated with this method is that the bacteria only kill the original tumor, but do not address metastases, which are what ultimately kill most cancer patients. In order to be truly effective, the treatment must combat metastatic disease.