Introduction: Cancer—A Part of Life
Cancer is not a modern disease. The attempts to understand and treat it did not burst onto the scene just recently. Cancer has been observed and described for millennia. Evidence of it has been found in human remains that go back many thousands of years. The famous anthropolo- gist Louis Leakey found the oldest possible tumor in a fossil jawbone in Kenya that dates back 6,000 years. Chinese folklore makes reference to esophageal and throat cancer. Ayurvedic medical books describe tumors and how to treat them. Hippocrates, the Greek physician, de- scribed cancer as a condition of excess black bile, which was one of the four humors. At that time, illnesses were categorized in terms of excesses of various bodily fluids—blood, phlegm, yellow bile, and the most malevolent of all, black bile.
It was not until the Renaissance in the 15th century that more was known about the anatomy and physiology of the human body. This knowledge, often gained from autopsies, eventually brought an end to the ‘excess of black bile’ theory of cancer. By the 1700s and 1800s the foundations were being laid for the use of surgery to remove cancerous tissues. Greater under- standing of cellular pathology followed this. In the mid-1900s, the structure of DNA was discov- ered, which has moved science and medicine to its present understanding of cancer. Yet, as advanced as genetic and epigenetic knowledge has become, it is certain that there will be more chapters to the story of cancer.
Cancer in Modern Times
Cancer in modern times can be distinguished from the past by the dramatic rate at which the disease has increased. Since the end of WWII in 1945, there have been exponential rises in the incidence of some cancers, particularly in the developed world. Lung cancer is a prime ex- ample. Breast cancer is another; according to King et al., a woman’s risk of getting breast can- cer in the 1940s was 1 in 22, whereas in 1970 it was 1 in 10 according to SEER (Surveillance, Epidemiology, and End Results) statistics, and today’s risk is 1 in 8.
Part of the increase can be explained by a greater life expectancy. In 1900, the average life expectancy in the U.S. was 47. Today, in most of the developed world, life expectancies ranges between the mid-70s to the early 80s. As cancer is predominately a disease of the aging, the longer people live, the higher the cancer rates will be.
Aging does not account for all of the increase. Some of the rise can also be attributed to fac- tors such as obesity, which is now the second leading cause of cancer behind smoking, as well as exposure to toxic substances and radioactive sources. Exposure to hormone disrupting chem- icals, and bacterial, viral and parasitical infections also account for significant number of can- cer occurrences.
In 1971 there were three million cancer survivors in the United States. The American Cancer Society estimates that in 2012 there were nearly 14 million Americans with a history of cancer, and by 2022 that number is expected to be 18 million. Each year since 1993, survival rates have improved. In 1975, the 5-year survival rate for Americans was 50%. In 2001 it was 65%. According to the most recent figures, that number is up to 68%. This trend is similar for most de- veloped nations.
Despite the improvement in mortality levels, the rate of cancer incidence remains sobering. At some point in their lives, usually later in life, a staggering number of people will be diag- nosed with cancer. In the United States, more than a third of women and nearly half of men are affected. One in three Australian women and one in two men will develop cancer by the age of 85. And in the UK, more than one in three will be di- agnosed at some point in their lives. These num- bers will only rise as the baby boomer generation ages. As the population grows older through the early 21st century, the number of people with cancer will also increase.
In 1970, 15% of American adults were obese. By 2010 more than 35% were obese. Even more concerning, 4% of children aged 6 to 11 were obese in 1970; 20% of that group were obese in 2010. While overall there is presently a decline in cancer mortality, the obesity epidemic may be responsible for pushing it back up.
Many thought that cancer would be solved by
now. That was the goal in 1971 when Richard
Nixon, then president of the United States, signed
the National Cancer Act, which became known as the War on Cancer. This euphemism is a re- flection on how modern-day thinking has militarized the relationship with cancer. However, the process of figuring out cancer is not a war; it cannot be eradicated with spectacular bombing raids or the use of a sledgehammer.