Wednesday, July 6, 2016

Cancer History

By Dr Ananya Mandal, MD

The study of cancer is termed oncology. Cancers have been known to mankind since ancient times. Cancer begins when cells in a part of the body start to grow out of control. Several different parts of the body may be affected by cancer.

Earliest References to Cancer
Some of the earliest evidence of cancer is found among fossilized bone tumors in human mummies in ancient Egypt, and references to the same has been found in ancient manuscripts. Bony skull destruction as seen in cancer of the head and neck has been found, too.

Although the word cancer was not used, the oldest description of the disease is from Egypt and dates back to about 3000 BC. It is called the Edwin Smith Papyrus and is a copy of part of an ancient Egyptian textbook on trauma surgery. It describes 8 cases of tumors or ulcers of the breast that were treated by cauterization with a tool called the fire drill. The description adds that there is not treatment for the condition.

Origin of the Word Cancer
The disease was first called cancer by Greek physician Hippocrates (460-370 BC). He is considered the “Father of Medicine.” Hippocrates used the terms carcinos and carcinoma to describe non-ulcer forming and ulcer-forming tumors. In Greek this means a crab. The description was names after the crab because the finger-like spreading projections from a cancer called to mind the shape of a crab.

Later Roman physician, Celsus (28-50 BC) translated the Greek term into cancer, the Latin word for crab. It was Galen (130-200 AD), another Roman physician, who used the term oncos (Greek for swelling) to describe tumors. Oncos is the root word for oncology or study of cancers.

Between 15th and 18th Centuries
During the beginning of the 15th Century scientists developed greater understanding of the workings of human body and its disease processes.

Autopsies, done by Harvey (1628), led to an understanding of the circulation of blood through the heart and body.

Giovanni Morgagni of Padua in 1761 regularized autopsies to find the cause of diseases. This laid the foundation for the study of cancer as well.

It was Scottish surgeon John Hunter (1728−1793) who suggested that some cancers might be cured by surgery. It was nearly a century later that development of anesthesia prompted regular surgery for “movable” cancers that had not spread to other organs.

The 19th Century
Rudolf Virchow, often called the founder of cellular pathology, founded the basis for pathologic study of cancers under the microscope. Virchow correlated microscopic pathology to illness.

He also developed study of tissues that were taken out after surgery. The pathologist could also tell the surgeon whether the operation had completely removed the cancer.

History of the Causes of Cancer
There have been numerous theories of causes of cancer throughout ages. For example, the ancient Egyptians blamed Gods for cancers.

Hippocrates believed that the body had 4 humors (body fluids): blood, phlegm, yellow bile, and black bile. He suggested that an imbalance of these humors with an excess of black bile in various body sites could cause cancer. This was the humoral theory.

After the humoral theory came the lymph theory. Stahl and Hoffman theorized that cancer was composed of fermenting and degenerating lymph, varying in density, acidity, and alkalinity. John Hunter, the Scottish surgeon from the 1700s, agreed that tumors grow from lymph constantly released from blood.

Zacutus Lusitani (1575−1642) and Nicholas Tulp (1593−1674), doctors in Holland, concluded that cancer was contagious. Throughout the 17th and 18th centuries, some believed that cancer was contagious.

It was in 1838 that German pathologist Johannes Muller showed that cancer is made up of cells rather than lymph. Muller proposed that cancer cells developed from budding elements (blastema) between normal tissues.

Rudolph Virchow (1821−1902), suggested that all cells, including cancer cells, are derived from other cells. He proposed the chronic irritation theory. He believed that cancer spread like a liquid. In the 1860s, German surgeon, Karl Thiersch, showed that cancers metastasize through the spread of malignant cells and not through a liquid.

Screening for cancer helps in early detection. The first screening test to be widely used for cancer was the Pap test. It was developed by George Papanicolaou as a research method in understanding the menstrual cycle. He then noted that the test could help in finding cervical cancer early and presented his findings in 1923.

It was then that the American Cancer Society (ACS) promoted the test during the early 1960’s and it became widely used as a screening tool.

Modern mammography methods were developed late in the 1960’s and first officially recommended for breast cancer screening by the ACS in 1976.

Development of Cancer Surgery
It was quite early in the history of knowledge of cancers that surgery was considered a modality of treatment of cancers. Roman physician Celsus had noted that despite surgery the cancer seems to come back. Galen wrote about techniques of surgery for cancers. Surgery then was very primitive with many complications, including blood loss. Surgery for cancers flourished in the 19th and early 20th centuries after advancement of anesthesia.

Bilroth in Germany, Handley in London, and Halsted in Baltimore are the pioneers of cancer surgery. William Stewart Halsted, professor of surgery at Johns Hopkins University, developed the radical mastectomy during the last decade of the 19th century for breast cancers. His work was based on W. Sampson Handley.

Stephen Paget, an English surgeon during this time found that cancers did spread via blood circulation. This understanding of metastasis became a key element in recognizing patients who might and might not benefit from cancer surgery.

Development of Radiation Therapy
In 1896 a German physics professor, Wilhelm Conrad Roentgen, discovered and presented the properties of X rays. It was within the next few months that X rays were used for diagnosis and in the next 3 years it was used in treatment of cancers. Radiation therapy began with radium and with relatively low-voltage diagnostic machines.

Development of Chemotherapy
It was seen that during the World War II, soldiers exposed to mustard gas during military action developed toxic bone marrow suppression. Soon a similar chemical nitrogen mustard was found to work against a cancer of the lymph nodes called lymphoma. This laid foundation for several new drugs that could be used against cancers.

Development of Hormone Therapy
In the 19th Century, Thomas Beatson discovered that the breasts of rabbits stopped producing milk after he removed the ovaries. He tried removal of the ovaries (called oophorectomy) in advanced breast cancer. This was discovered before the hormone itself was discovered. His work provided a foundation for the modern use of hormone therapy, such as tamoxifen and the aromatase inhibitors, to treat or prevent breast cancer.

Development of Immunotherapy
With the understanding of the biology of cancer cells, several biological agents have been developed in treatment of cancers. These are called biological response modifier (BRM) therapy. Notable among these are the monoclonal antibodies.

The first therapeutic monoclonal antibodies, rituximab (Rituxan) and trastuzumab (Herceptin) were approved during the late 1990’s to treat lymphoma and breast cancer, respectively. Scientists are also studying vaccines that boost the body’s immune response to cancer cells.

The later part of the 20th century also saw the development of targeted therapies like growth factor inhibitors like trastuzumab (Herceptin), gefitinib (Iressa), imatinib (Gleevec), and cetuximab (Erbitux). Another targeted approach is anti- ngiogenesis or anti-blood vessel formation drugs like bevacizumab (Avastin).

From: news-medical.net


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