Today, 4 February 2014, is World Cancer Day. To mark this occasion, here is a brief article that looks at the ‘history’ of cancer:
Cancer is one of the leading causes of death throughout the world. In developed nations, an estimated 1 in 3 people will be diagnosed with cancer. Today, as the disease becomes an increasing threat throughout the world, a focus is placed on research for treatment and cures. A look back at the history of cancer sheds light on how societies before ours dealt with this formidable malady.
The first cancers
The oldest descriptions of cancer can be found in ancient manuscripts. Fossilized bone tumors and the records of Egyptian mummies provide material evidence of ancient cancers. The oldest known account of cancer was discovered in Egypt and dates from approximately 1600 B.C.E. The papyrus in which this account is found described eight cases of tumors or ulcers of the breast that ancient physicians treated by cauterizing with a tool called the “fire drill.” The papyrus continues the narrative by stating, “There is no [effective] treatment.”
Not until about twelve centuries afterward did such tumors gain their modern name—cancer. The word “cancer” is credited to the Greek physician Hippocrates (460-370 B.C.E.). Considered the “Father of Medicine,” Hippocrates employed the words carcinosand carcinoma in his descriptions of non-ulcer forming and ulcer forming tumors. Hippocrates also believed that cancer resulted when the four “humors” (or bodily fluids—blood, phlegm, yellow bile, and black bile) fell out of balance with one another allowing black bile to collect in excess in whichever part of the body the cancer affected.
In Greek, carcinos refers to the familiar zodiac sign Cancer, the Crab. The Greeks applied the term “crab” to the disease because of the tendril-like projections, which resemble the ten-legged sea creature. In modern medicine, a carcinoma (arising from epithelial cells) is the most common type of cancer, the other types being sarcoma (from connective tissue), lymphoma (from blood cells), germ cell tumors (from totipotent, or reproductive, cells), and blastic tumors (from immature tissue).
The next great wave in cancer scholarship and understanding came with the Renaissance when scholars began to refine their understanding of the human body. Following the development of the modern scientific method in the Renaissance, scientists began to apply it to the study of disease. The English physician and scientist William Harvey (1578-1657) used autopsies to identify and understand the circulatory system that had previously been a mystery. Later, Italian anatomist Giovanni Morgagni (1682-1771) laid the foundations for scientific oncology (the study of cancer) by performing autopsies and relating the patient’s illness to the pathology found after death.
Scottish surgeon John Hunter (1728-1793) suggested that some cancer could be cured with surgery and described how the surgeon should decide upon which cancers to operate. If the tumor had not invaded nearby tissue and was pliable, he said, “There is no impropriety in removing it.” The invention of anesthesia in the nineteenth century allowed the practice of oncological surgery to flourish and physicians developed what became standard cancer operations, such as the radical mastectomy.
The invention of the modern optical microscope in the nineteenth century was another boon to scientific oncology. The German physician Rudolf Virchow (1821-1902) combined Morgagni’s pathology techniques with the microscope to correlate the microscopic pathologic evidence of a patient’s illness. The microscope facilitated the rise of precise cancer diagnoses in medicine.
After body tissues were removed, either from living patients via biopsy or deceased patients during an autopsy, the cells found could be examined under a microscope and differentiated—a technique that still forms the basis of cancer diagnosis today. This differentiation allowed doctors to better understand how cancers functioned within the human body. Because of these developments, much more accurate theories began to evolve during the late nineteenth century and early twentieth century as to the origins and pathways of cancer.
The theories of the origin of cancer were as varied as they were wrong throughout history. Egyptians blamed cancer on the intervention of the gods. Greek physicians relied on Hippocrates’ theory of cancer arising from an imbalance between the four humors of the body. Roman medicine continued this humoral theory of cancer. The prominent Roman physician Galen particularly embraced this teaching and it continued unchallenged for over thirteen centuries throughout the Middle Ages because restrictive social mores prohibited examination of the human body, especially through autopsies.
The Lymph Theory
Further theories preceding the invention of the modern microscope include the “lymph theory” of cancer. This theory was one of the first theories to replace Hippocrates’ humoral theory. The lymph theory purported in the early eighteenth century that cancer formed because of fermenting and degenerating lymphatic fluid. John Hunter, the Scottish surgeon who anticipated the advent of oncological surgery, supported the lymph theory.
The Parasite Theory
Another theory in the seventeenth and eighteenth centuries was the “parasite theory.” This theory alleged that cancer was an infectious disease that relied upon the transmission of an invisible contagion. The parasite theory persisted off and on until the twentieth century. In 1926 an oncological scientist named Johannes Fibiger earned a Nobel Prize for research erroneously finding that certain worms caused stomach cancer. Later, other scientists disproved this theory.
More modern, scientifically sound theories replaced these previous theories. One such theory was the “blastema theory.” The German pathologist Johannes Müller (1801-1858), who mentored Rudolph Virchow, developed the blastema theory in 1838. The blastema theory postulated that cancer was made up of cells and not lymphatic fluid and that cancer cells arose from budding elements (called blastema) between normal tissues. Virchow then theorized that cancer spread like liquid through chronic irritation of tissues. German surgeon Karl Thiersch (1822-1895) proved that cancers metastasize through the spread of malignant cells, not liquid.
Developed in the end of the nineteenth century and lasting through the 1920s, a further theory developed that hypothesized that cancer was caused by trauma or injury. Scientists finally disproved this theory by failing to induce cancer on laboratory animals through injury. All of these theories eventually faltered, but they paved the way for scientific advances to come.
The greatest leaps in scientific knowledge of the biology, treatment, and prevention of cancer came during the latter half of the twentieth century. By about 1950, scientists possessed the instruments necessary to begin solving the chemical and biological complexities of cancer. In 1953, James Watson (b. 1928) and Francis Crick (1916-2004) made the key discovery of the chemical structure of deoxyribonucleic acid (DNA).
DNA is the basis of the genetic code that directs cell activity. Decoding DNA allowed scientists to understand how genes work and how mutations can damage them. DNA showed that damage done to it by chemicals, radiation, viruses, and inherited disease sometimes cause cancer. In other words, carcinogens can cause genetic damage in the form of mutation. Mutations can lead to abnormal groups of cells, which evolve into more malignant cells over time. Cancer progresses as the genetic mutation reproduces. This discovery answered many questions that had troubled scientists for generations.
During the 1990s, medical scientists began to unlock the knowledge of which genes, if damaged by carcinogens or inherited mutations, could lead to cancer. A notable example of this genetic identification was the case of the BRCA1 and BRCA2 genes in the early 1990s. These genes, short for “BReast CAncer” types 1 and 2, indicate a considerably higher risk of developing breast cancer. The discoveries of these two genes give hope that inherited and genetic susceptibility to cancer can be discovered early so that medicine can intervene.
Other genes discovered, so far, can be associated with many cancers that run in families such as cancers of the kidney, ovary, colon, rectum, esophagus, lymph nodes, pancreas, and skin. While inherited cancers are not as common as spontaneous cancers, accounting for less than fifteen percent of all cancers, it is important to understand these cancers because continued genetic research may enable scientists to identify all persons at high risk, which in turn promotes prevention and early intervention.
The War on Cancer
Modern medicine’s war on cancer over the past 60 years has obscured the long history of cancer diagnosis, treatment, and prevention. Written records trace the history of cancer over 3,600 years and archaeological evidence of cancers extends even farther into the past. The devastating effects of cancer and scientists’ attempts to combat them over thousands of years put into perspective just what a potent enemy cancer is and has been throughout history.
Sarah Jane Bodell