ELI5: Why is cancer called "Cancer?"

The earliest known descriptions of cancer appear in seven papyri, discovered and deciphered late in the 19th century. They provided the first direct knowledge of Egyptian medical practice. Two of them, known as the "Edwin Smith" and "George Ebers" papyri, contain descriptions of cancer written around 1600 B.C., and are believed to date from sources as early as 2500 B.C.

Hippocrates (ca. 460 BC – ca. 370 BC) described several kinds of cancer, referring to them with the Greek word carcinos (crab or crayfish), among others.[1] This name comes from the appearance of the cut surface of a solid malignant tumour, with "the veins stretched on all sides as the animal the crab has its feet, whence it derives its name".[2] Since it was against Greek tradition to open the body, Hippocrates only described and made drawings of outwardly visible tumors on the skin, nose, and breasts. Treatment was based on the humor theory of four bodily fluids (black and yellow bile, blood, and phlegm). According to the patient's humor, treatment consisted of diet, blood-letting, and/or laxatives. Through the centuries it was discovered that cancer could occur anywhere in the body, but humor-theory based treatment remained popular until the 19th century with the discovery of cells.

Celsus (ca. 25 BC - 50 AD) translated carcinos into the Latin cancer, also meaning crab. Galen (2nd century AD) called benign tumours oncos, Greek for swelling, reserving Hippocrates' carcinos for malignant tumours. He later added the suffix -oma, Greek for swelling, giving the name carcinoma.

The oldest known description and surgical treatment of cancer was discovered in Egypt and dates back to approximately 1600 BC. The Papyrus describes 8 cases of ulcers of the breast that were treated by cauterization, with a tool called "the fire drill." The writing says about the disease, "There is no treatment."[3]

http://en.wikipedia.org/wiki/History_of_cancer#Early_diagnoses

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