In the late 1800s, a patient suffering from a tumor growing on his cheek had a miraculous recovery after becoming infected by streptococcus pyogenes bacteria. It seemed as though the fever had burned away the tumor.
Afterward, Dr. Coley, a bone surgeon and cancer researcher at New York Cancer Hospital, observed that several other cancer patients who had recently undergone tumor-removal surgery were more likely to recover from their cancer if they developed a post-surgical infection.
Dr. Coley, in an attempt to figure out why, began injecting inoperable cancer patients with streptoccal bacteria. These became known as “Coley toxins.” In one case, Coley treated a 21-year-old man with a mix of bacteria and bacterial lysates. This patient then had a complete remission.
Dr. Coley injected over 1,000 patients with his toxins, unfortunately he never properly documented all his cases or followed up with enough patients.
After his death in 1936, the medical community dismissed his methods in favor of radiation and chemotherapy. Only recently have cancer researchers started to revisit his work, and now refer to Dr. Coley as the “father of immunotherapy.”
In 2014, the FDA approved an immunotherapy drug for melanoma. Anti-PD1 soon became the standard care for melanoma. It is so effective that it can be used alone without the help of chemotherapy or radiation.
Immunotherapies work by hacking the immune system and essentially teaching it how to attack cancer cells. Immunotherapy has a long-term impact on cancer unlike chemotherapy and radiation.
Larger clinical trials on humans are in the works. Unfortunately, it is difficult to predict how well treatments that have been successful in animals trials will translate to people.
The largest obstacle to overcome is the differing tissue colonization in humans and in mice and rats. However, if this obstacle is overcome, bacteria can become a useful vehicle of tumor destruction.