Cancer in Perspective
Ann entered the consultation room looking rather forlorn. There was some pain, she said, and a little hardening on the right breast. Was it cancer, she asked, a tone of urgency and dread. Her mother had died from some cancer, at sixty, but she could not tell what it was. Not long before, Kenya had lost two prominent figures to cancer. Everyone. Kenyans were demanding that cancer be declared a national emergency, like HIV/AIDS, some years back. The government promised some policy. On the roads in Nairobi, billboards went up announcing cancer insurance. And Ann entered the consultation room, demanding to know everything about cancer.
“Everything?” I asked incredulously.
“Yes, everything.” She said, looking at me sternly, her hand on her right breast.
What is cancer?
Everyone has a right to know everything about cancer. But no one does, and no one can. It helps to begin from what it is not.
Cancer is not a single disease like diabetes or high blood pressure.
Cancer is not a kind of infection and cannot be passed from person to person.
Cancer is not a death sentence; outcomes depend on the type, treatment undertaken and especially the stage at diagnosis
But what is it?
It is a collection of diseases all caused by abnormal growth of body cells. Certain mechanisms keep cell division under control. When these mechanisms do not work, the cells divide continuously, leading to the growth of a tumor, which is essentially a mass of abnormal cells.
Cancer can involve any tissue in the body. Those with the highest rate of cell division have the highest likelihood of developing cancer. This is because the basis of cancer is a breakdown of the orderly process of cell division. The fasters cells divide, the more likely the control mechanisms will break down.
The breakdown in cellular control means that old and damaged cells that should die fail to die. New cells are formed where none should be formed. This implies an accumulation of abnormal cells forms a swelling or growth, which is called a tumor. But in cancers of the blood, no tumor is formed. Instead, the abnormal cells accumulate so much that they overwhelm the circulation and other types of blood cells are either markedly reduced or absent altogether.
Types of cancer
There are very many types of cancers. The classification is largely based on the organs or tissues involved, thus breast cancer, bone cancer, prostate cancer, or lung cancer. However, every organ has many different types of cell groups, and the detailed classification of cancers used by doctors for diagnostic and therapeutic purposes are based on cellular and molecular characteristics. Thus breast cancers are further grouped in more detailed classes that are important for treatment purposes. You can find more details on the specific types of cancers.
How is cancer caused?
Cancer is fundamentally a genetic disease. It is caused by abnormal changes in a person’s genes that affect cell growth and function. The reason why cancers seem to have a familial pattern is that genes are the basis of biological inheritance. A person may inherit genetic changes from their parent that predispose them to cancer. Environmental exposures also contribute to genetic differences. The cumulative effects of exposure to substances in food, smoke, solar radiation cause damage to the DNA leading to the breakdown of cellular growth control mechanisms.
The interplay between inherited and secondary genetic changes means that cancer is highly variable between individuals and even within the same person. As cell division goes out of control, more and more errors accumulate. The mechanisms that cause and drive cancer growth also cause the high variability that makes treatment challenging.
How does cancer spread?
One of the worst things about cancer is that it is not confined to the primary tissue. Cancer cells can spread through blood or lymphatic systems to distant organs and grow within these organs. Thus, breast cancer can spread to the lung and or lung cancer to bones. The lack of control mechanism means that the cancer cells can establish a focus of growth and proliferation in the new site, something normal cells cannot.
The spread of cancer is called metastasis, a term whose original Greek means a rapid transition from one point to another. If breast cancer spreads to the lungs, it is called metastatic breast cancer. It does not become lung cancer but retains the cellular characteristics of the primary breast cancer, thus the description of malignant breast cancer. Metastasis affects cancer staging and treatment options, usually for the worse. Nearly all cancers diagnosed late have spread to other organs, although some spread faster than others.
So is this breast cancer?
No, it isn’t. Not all cellular changes are cancerous. Cells are sensitive to bodily changes such as levels of hormones and may increase when hormone levels rise. This is why some people experience tender breast swelling during the menstrual cycle, which then disappear. Breast lumps with cyclical patterns are unlikely to be malignant. Persistent ones should always be considered suspicious. A mammogram is recommended. Your doctor should guide you on the need for and findings of a mammogram and a periodic examination and check-up.