Of all the diseases that afflict humanity, cancers are some of the deadliest and most ancient.
According to the World Health Organization (WHO), almost 9 million people died of cancers in 2015, making them the second-most common cause of death. Lung cancer alone was responsible for almost 1.7 million fatalities.
The earliest writings on the subject are from over 3,500 years ago. Two ancient Egyptian documents —the Ebers and Edwin Smith papyri, both from around 1600 bc — describe a condition we now recognize as breast cancer. The Ebers Papyrus even describes surgery to cut away the tumour and cauterization to seal the wound. Other ancient writings also speak of such conditions, including passages from the Code of Hammurabi, the Rites of the Zhou Dynasty and even the Ramayana. And the disease itself is far older than even that — the earliest evidence includes bone tumours found in fossilized hominid remains from four million years ago.
The name itself comes from the Greek word for ‘crab’ — karkinos (or carcinos) — from the writings of Hippocrates, also known as the Father of Medicine. The Hippocratic Oath for doctors, including the principle of ‘either help or do no harm’, also came from his writings. Why Hippocrates chose to call this disease ‘crab’ is a matter for speculation, but it likely had to do with what cancer looks like — a raised tumour with veins radiating outward like a crab’s feet — and also for its dogged tenacity in resisting treatment.
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At one level, this is a morbidly fascinating disease, since it is intimately related to the same processes that create and sustain life — cell growth and division. The same mechanisms that result in the formation of skin, blood, bone and organs in a foetus, or on a more everyday level, are responsible for cuts and bruises healing on their own, are at the heart of many kinds of cancers.
In a nutshell, cell growth and replication, which take place literally all the time in healthy bodies, occur under tightly regulated biochemical conditions. For instance, the constant ‘replication’ of new cells is balanced by the constant ‘recycling’ of old ones, which takes place by a process called apoptosis. Processes like these ‘start’ and ‘stop’ in response to specific biochemical ‘signalling systems’. For instance, when you cut your finger, a biochemical signal tells skin cells in the area to begin dividing and growing faster than normal.
When the cut has healed — when there is no ‘gap’ left for new cells to fill — another signal ends that process, bringing the growth rate of new cells back into balance with apoptosis. When these signalling systems fail — which, as it turns out, can happen for a variety of reasons, some understood and many yet to be fully comprehended — it leads to unrestrained cell growth and replication. Cells pile upon cells, at first a small clump and then a larger growth, a relentless and unbridled process that produces a ‘tumour’. When these tumours appear in the organs such as the stomach, lungs or anywhere else, they interfere with normal bodily functions, often leading to death.
That being said, abnormal cell growth is only one part of cancer. Another attribute of cancerous cells is that they invade other tissues and organs, not just in their immediate proximity. By entering blood vessels and lymphatic systems (the highways of the human body), cancerous cells can appear at sites far away from where they first formed. For instance, they can begin in the lungs and spread to the stomach and intestines. In modern medicine, these two characteristics — abnormal cell growth and the spreading of such abnormal cells to other parts of the body — are a big part of what qualifies a condition as a cancer.
Extracted with permission from Life after Cancer: An Essential Guide for Patients and Caregivers by Dr Mrinal Kaushik and Aditya Wig, published by Bloomsbury India.