The incidence of cancer is rising. More people are being diagnosed with cancer and the age at which cancer is diagnosed is decreasing. A diagnosis of cancer, or even the possibility of one, can be overwhelming. Understanding the fundamental nature of the disease is the first step toward empowerment. This guide explains the basics of cancer in simple terms.
Our Body’s Cells: A Community at Work
Cancer is caused by defective cells. Cells are the building blocks of our body. The human body can be thought of as a vast and organised community made up of trillions of individual cells. Each cell has a specific job to do. Working together the cells keep the body functioning normally.
Every community has rules. The rules are important for the survival and normal function of the community. The body also has rules. Among the most critical rules are rules that govern the cell numbers. Normal body cells follow a very orderly process: they grow, divide to create new cells when the body needs them, and eventually die when they become old or damaged. This cycle of growth, division, and death is tightly controlled by instructions within each cell, ensuring a perfect balance.
When Control is Lost
Cancer begins when this orderly process breaks down. It is believed that cancers originate from a single abnormal cell. This cell refuses to follow the rules of growth and division. It grows uncontrollably giving rise to more cells that inherit its delinquent nature. Unlike normal cells, these abnormal cells do not die when they should. Instead, they continue to divide, creating more and more abnormal cells that share the same defects.
What are Tumours?
As these out-of-control cells accumulate, they form a mass or lump of tissue known as a tumour. All tumours are not cancerous. Tumours can be malignant or benign. Cancers are malignant tumours. Benign tumours grow uncontrollably, usually the growth is slow, they don’t invade the normal organs in the vicinity and do not spread to other parts of the body. Removing the benign tumour surgically cures the person of the disease. Malignant tumours grow fast invade adjacent organs and spread to other parts. Over the years malignant tumours have become more and more curable. The therapy is complex and may be prolonged. The success depends on the stage at which the cancer is diagnosed and the type of the tumour.
Cancer is Not Just One Disease
The term “cancer” does not refer to a single illness. It is a broad term for a group of more than 100, or by some counts over 200, distinct diseases. Each type of cancer is unique, with its own set of characteristics, growth patterns, and response to treatment. Cancers are typically named after the organ or type of cell in which they first originate. For example, a cancer that begins in the breast is called breast cancer. If this cancer spreads to the lungs, it is still classified and treated as breast cancer, not lung cancer; it is referred to as metastatic breast cancer.
Key Characteristics of Cancer Cells
Cancer cells behave very differently from their normal counterparts. Understanding these differences helps explain how cancer affects the body. In simple terms, cancer cells:
- Grow without permission: They can multiply without receiving the normal “go” signals that healthy cells require to divide.
- Ignore “stop” signals: They disregard the signals that tell healthy cells to stop dividing. Normal cells stop growing when they come into contact with other cells, but cancer cells escape this control.
- Evade self-destruction: Cells that have sustained irreparable damage die by a process called apoptosis. This is a defence against propagating defective cells. Cancer cells are able to bypass this crucial safety mechanism and propagate despite of being defective.
- Invade and spread: Unlike normal cells that stay in their designated area, cancer cells can invade nearby tissues and organs. They can also break away and travel to distant parts of the body to form new tumours.
- Tricking the body: Cancer cells can trick the body into helping them survive by providing them with nutrients. They can stimulate the growth of new blood vessels to supply them with oxygen and nutrients. They can hide from or manipulate the body’s immune system to avoid being destroyed.