Only a few decades ago, many hesitated to say the word cancer aloud, as if merely mentioning it might invite the disease into one’s body. But in fact, the "C-word" has long been known—and feared.

Sometime around 400 B.C., Hippocrates (460-370, B.C.), is said to have named the disease karkinos [from the Greek, for crab]. Historians have offered many explanations for his odd choice, all of them equally intriguing and difficult to prove. According to one account, when Hippocrates examined patients with malignant cancer, he found large masses, or tumors, that protruded through the skin. These tumors were rock hard, exquisitely painful, and often topped with ulcerating, bleeding, or oozing sores that refused to heal. The hardness of these tumors, much like the protective shell of a crab, is said to have inspired his name choice. Others have argued it was because the pain of a malignant tumor is much like the sharp pinching of a crab’s claw. An alternative version suggests the tenacity with which a crab bites and refuses to let go resembled how stubbornly a malignant tumor adhered to the body, no matter how it was manipulated.

Hippocrates hypothesized that an excess of black bile caused these tumors; it was a concept that remained medical doctrine for over two millennia. He also observed that while some masses were benign and not terribly life-threatening, others, such as breast, uterine, mouth, skin, stomach and rectal cancers—all very common in the Ancient World—tended to spread quickly through the body, resulting in death.

In approximately 47 A.D., the Greco-Roman philosopher Aulus Cornelius Celsus (25 B.C.-50 A.D.) authored a definitive encyclopedia on medicine called De Medicina. In deference to Hippocrates, he called the disease cancer [the Latin equivalent of crab]. And so it remains to this very day.

During the second century A.D., the eminent physician and anatomist Galen of Pergamon (131-201, A.D.) extended Hippocrates' metaphor even further. While dissecting and describing breast cancer tumors, he famously declared that their swollen veins and tributaries looked "just like a crab’s legs extended outward from every part of its body."

Although there are numerous references to cancer in medical texts published during Antiquity, the Middle Ages, the Renaissance and the Enlightenment eras, physicians debated for centuries about its precise cause. They also often confused malignant tumors with what came to be called cankers, ulcerating sores caused by a variety of infectious and inflammatory conditions, as well as gangrene and other maladies.

Indeed, it was not until the mid-nineteenth century that scientists began to appreciate the cellular mechanisms of cancer, by looking at malignant tumor cells though the microscope. Pathologists discovered that unlike healthy cells, cancer cells proliferated uncontrollably, destroyed the adjacent, healthy tissue, and often spread via lymphatic and blood vessels to other parts of the body.

In the century and half that followed, scientific inquiry created a whole new field of medicine called oncology [from the Hippocratic term, onkos, or masses]. As a result, today’s doctors are much better able to diagnose, distinguish, and successfully treat the many different types of cancer that afflict humankind.

Of course, this long and arduous quest is far from over and there remains much more work to be done before cancer is relegated to the history books. But that is another story of science and healing that deserves its own conversation. Suffice it to say, as we gain ever more success in fighting an age-old foe, we have become far more willing to utter this crabbiest of words in public.

In this segment, we'll talk about the origins of the word 'cancer' and the history of its meaning.