Sunday, July 31, 2016

Coley's Toxins

From an interesting Times article on new therapies that prime the body's immune system to fight cancer, I extract this on an unwitting pioneer of these treatments:
Dr. William B. Coley, an American surgeon born in 1862, is widely considered the father of cancer immunotherapy. But he practiced a crude form of it, without understanding how it worked.

Distressed by the painful death of a young woman he had treated for a sarcoma, a bone cancer, in 1891, Dr. Coley began to study the records of other sarcoma patients in New York, according to Dr. David. B. Levine, a medical historian and orthopedic surgeon.

One case leapt out at him: a patient who had several unsuccessful operations to remove a huge sarcoma from his face, and wound up with a severe infection, then called erysipelas, caused by Streptococcal bacteria. The patient was not expected to survive, but he did — and the cancer disappeared.

Dr. Coley found other cases in which cancer went away after erysipelas. Not much was known about the immune system, and he suspected, mistakenly, that the bacteria were somehow destroying the tumors. Researchers today think the infection set off an intense immune response that killed both the germs and the cancer.

Dr. Coley was not alone in believing that bacteria could fight cancer. In a letter to a colleague in 1890, the Russian physician and playwright Anton Chekhov wrote of erysipelas: “It has long been noted that the growth of malignant tumors halts for a time when this disease is present.”

Dr. Coley began to inject terminally ill cancer patients with Streptococcal bacteria in the 1890s. His first patient, a drug addict with an advanced sarcoma, was expected to die within weeks, but the disease went into remission and he lived eight years.

Dr. Coley treated other patients, with mixed results. Some tumors regressed, but sometimes the bacteria caused infections that went out of control. Dr. Coley developed an extract of heat-killed bacteria that came to be called Coley’s mixed toxins, and he treated hundreds of patients over several decades. Many became quite ill, with shaking chills and raging fevers. But some were cured.

Parke-Davis and Company began producing Coley’s toxins in 1899, and continued for 30 years. Various hospitals in Europe and the United States, including the Mayo Clinic, used the toxins, but the results were not consistent.
I wonder what other promising medical treatments lie buried in the records of 19th-century medicine, shunted aside when exciting new technologies like radiation became available.

Incidentally I am a long-term optimist about cancer. Unlike bacteria, cancers can't adapt to our treatments, so once we find a cure for a particular type it ought to work for a long, long time. Cancer treatments can be honed to strike cells with particular mutations, so unlike treatment for, say, heart disease, or depression, we can fix problems in one area without causing just as many somewhere else. Our knowledge about genes, proteins, and cells continues to grow exponentially. I consider the exciting therapies described in the Times to be the primitive precursors of vastly better techniques to come. I don't see why we can't nearly eliminate cancer deaths within a century.

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