Tuesday, April 23, 2024

A History of Cancer

 A History of Cancer Treatment


Ancient physicians were aware that cancer often came back after it was surgically removed. The thinking for centuries was that a patient was incurable after a diagnosis of cancer had been made.


Cancer treatment developed slowly over the ages. Ancient physicians realized there was no way to treat cancer once it spread, and they felt that intervention might be more harmful than no treatment at all. Major advances in cancer surgery were not made until the 19th and early 20th centuries.


Because of the slowness with which an understanding of cancer improved, fear of the disease became commonplace. Even today with much improved treatments and cure rates many people still consider cancer incurable and put off treatment until it is too late.


There were talented surgeons before the discovery of anesthesia who were known for their swift and precise surgery. Anesthesia became available in 1846. After that, surgical skills advanced so quickly that the next hundred years became known as the “century of the surgeon.”


Towards the end of the 20th century surgeons became extremely proficient in minimizing the amounts of normal tissue removed during cancer operations. In addition, up until that time period, diagnosing cancer usually required exploratory surgery to take tissue samples to be tested for cancer. In the 1970’s, progress in ultrasound technology, as well as CT scans, MRI and PET scans greatly reduced the number of exploratory surgeries.


Treatment of cancer with radiation therapy and chemotherapy have a storied history as well. 


The X-ray was discovered in 1896. It was called X-ray because x is the algebraic symbol for an unknown quantity.  Systems were quickly devised to use x-rays for diagnosis, and within three years radiation was used to treat cancer. However, early in the 20th century it was discovered that radiation could cause cancer as well as cure it. Early radiologists used the skin of their arms to test the strength of radiation to arrive at an estimate of a safe daily dose of radiation. Predictably many of them developed leukemia from regular exposure to radiation.


The last twenty five years of the 20th century saw advances in radiation physics and computer technology combine to make it possible to aim radiation more precisely and to more accurately control the intensity. This combined control of aim and intensity made it possible to decrease the radiation reaching normal tissue while delivering a high dose to the cancer. 


As advances continue to develop, radiation therapy has been adapted to use proton beams instead of x-rays; proton beams do even less damage but are very effective at killing cells. Radiologists can now deliver large, precise radiation to small tumors, and also deliver radiation at the time of surgery. They also have chemical modifiers or radiosensitizers available to them that make cancer cells more sensitive to radiation.


The use of chemotherapy to treat cancer has its roots in World War II. Naval personnel who were exposed to mustard gas were found to experience toxic changes in bone marrow cells. A compound called nitrogen mustard was found to work against cancer of the lymph nodes. This was the beginning of a long series of more effective agents that could be used to kill rapidly growing cancer cells.


Sidney Farber of Boston demonstrated that the use of aminopterin (related to the vitamin folic acid) resulted in remission in children with acute leukemia. That led to a drug called methotrexate, a cancer treatment drug that is widely used today. Metastatic cancer was first cured in 1956, and methotrexate was the miracle drug.


Chemotherapy began to show dramatic results in the 1960’s. Long-term remissions and cures of patients with Hodgkin disease and childhood acute lymphoblastic leukemia were achieved in that decade. Cures of testicular cancer occurred in the 70’s. 


In a relatively short time, cancer treatment evolved from surgery only, to include radiation therapy and, finally, chemotherapy. Early in the 20th century cancers were considered curable only if they were localized enough to be removed surgically. Eventually radiation was used to control small tumor growths after surgery. Then chemotherapy was added to destroy small tumor growths. Eventually the power of chemo was amplified by using multiple chemotherapy drugs together. Some fast growing leukemia, and lymphoma responded very well to combination chemo.


The history of cancer treatment is not exactly a glamorous topic, but it does highlight the amazing advances that the medical community can initiate. Rapidly evolving and increasingly ingenious approaches that improve quality of life and even save lives.


Cancer treatment may not be glamorous, but it is pretty close to a miracle.