Cancer

I just finished reading The Emperor of All Maladies: A biography of cancer, by Siddhartha Mukherjee. I have a quibble with the title -- it should be history, not biography. By personifying cancer, he plays into just the mythologizing he is trying to dispel. But that aside, I found the book very informative. 

I knew the general outline of the story, but not a lot of the details. What I want to comment on here, which I believe is the key takeaway, is that medical practice is subject to ideological capture, even in the modern era of "scientific" medicine. In the center of the book is the horror story of radical mastectomy. Before the true nature of cancer was understood, surgeons responded to breast cancer by what I can only describe as savage  butchery. They not only removed the breasts and surrounding lymph nodes, but underlying muscle and bone, creating ghastly disfigurement and disability. Leading surgeons competed with each other to commit the most ghastly assaults on their patients, boasted loudly of the extremism of the damage they inflicted, and reacted to criticism with sneering disdain. 

All this was based on the assumption, entirely false as it turns out, that cancer spreads concentrically. In other words, they removed all of these body parts because they presumed that metastasis was confined within a radius of the original tumor and they were removing all of the places it could lurk. They were wrong.

Cancer cells can break off an travel through the blood stream to anywhere in the body. Either the cancer was still confined within the original lesion, in which case just removing the tumor would be completely curative; or it was too late to cure it by surgery. Not until the 1980s did physicians understand the nature of cancer, that it consists of cells whose genomes have mutated so they replicate uncontrollably. They also learned that there are innumerable different cancer producing mutations and types of cancer cells. 

Originally, chemotherapy consisted of chemicals which indiscriminately prevent cell division, or kill dividing cells. This did suppress cancer, but of course normal cells also need to divide, particularly the stem cells in the bone marrow that differentiate into the various types of blood cells. This means there is a limit to the amount of chemotherapy you can inflict on a person without killing them. So the next big fad in cancer treatment was called autologous bone marrow transplant. This meant extracting marrow from the patient, giving doses of chemotherapy so high it completely wiped out the bone marrow, which ordinarily would have killed the woman; and then reimplanting the reserved marrow so that it could regrow. Although women usually survived the treatment, it caused appalling suffering and long term damage.

People were so convinced this was effective that there was a passionate political movement to make it available without rigorous clinical trials. Countless women went through the hell of bone marrow transplant chemotherapy. But it turns out the only evidence of its effectiveness was a fraud perpetrated by a South African physician. 

Radical mastectomy and bone marrow transplant for this purpose are no longer performed. (There are other reasons for bone marrow transplants, to be clear.) Now that cancer is better understood, there are so-called targeted therapies that can treat cancer with specific characteristics, which have much less severe side effects than indiscriminate chemotherapy; and surgery for breast cancer is far less drastic. But could medical practice be going down some wrong roads today? Certainly. We need to be far more diligent about basing medical intervention on good evidence. That's why the so-called "right to treat" movement is so misguided. Giving people unproven treatments is not doing them any favors.