What is Cancer?
Cells are the basic building blocks of life. All living tissues are made of cells and there are hundreds of different types of cells in the body. Each type has a specific function. Blood cells carry oxygen, nerve cells carry instructions, skin cells protect our bodies, and so on.
Each cell is very small. Packed together, six million blood cells (or cancer cells) are no larger than a strawberry seed. All cells contain DNA, a special kind of molecule that contains our genetic code. DNA controls all of a cell’s functions, including reproduction. If the DNA is damaged in a certain way, the cell may reproduce uncontrollably and such uncontrolled growth is the beginning step in cancer development.
Substances that cause cancer-producing DNA damage are called carcinogens. These include a few specific viruses, some natural substances (tobacco, asbestos, etc), chemicals, and some types of radiation. The interval between exposure to a carcinogen and the development of cancer is usually years to decades. There are many carcinogens that affect humans. However, for most human cancers we cannot look back in time and identify the carcinogen or clear cause for the cancer. Indeed, most cancers in humans have no single dominant cause. Most cancers arise because of many factors, only one of which may be exposure to an identifiable carcinogen. Other factors include things like age, diet, lifestyle choices, and unique aspects of a person’s genetic code that make him or her more vulnerable to developing cancer.
Cancer is defined by uncontrolled cell growth along with the ability to spread and grow in other parts of the body. This uncontrolled growth is very slow at first. Many cancers spend years or decades before spreading. Over time, however, growing cancer cells can change and become able to spread (metastasize) to other parts of the body. It is this ability to spread that makes it a potentially life-threatening disease.
A good example of a cancer that grows slowly and almost never spreads is the common skin cancer basal cell carcinoma, which is almost 100% curable. Some cancers, however, have frequently spread before they are detected; this is often the case for cancers of the lung and pancreas.
Cancers of the same type may look and behave similarly. For example, breast cancers in two different women may look very similar under the microscope and may be vulnerable to the same anti-cancer drugs (chemotherapy). These common features allow doctors to predict—within reason—how a given type of cancer will behave and how it may respond to treatment. This knowledge guides doctors in making treatment recommendations. Despite these common features, every cancer is unique, and the outcome of one person with breast cancer cannot predict the outcome of another person with breast cancer.
Popular theories suggest that cancer is caused by pollution and is a ‘curse’ on modern society. This is incorrect. Some cancers are from human-made carcinogens, but most carcinogens are naturally occurring. Examples include tobacco, asbestos, and the cancer-causing viruses. Humans can make the unwise decisions to smoke tobacco and line buildings with asbestos, but these substances themselves are not new. Cancer is as old as life itself and has been found in dinosaur fossils and in the mummified bodies of ancient humans.
Cancers threaten a patient’s life by spreading to and damaging other organs in the body. Cancer that spreads to the lung can cause shortness of breath and pneumonia. Cancer that spreads to the brain can cause symptoms similar to a stroke. Cancer has other effects that may not relate to spreading to and damaging a particular organ. Many cancer cells secrete chemicals or hormones that cause weight loss, weak bones, fevers, fatigue, a vulnerability to infections, and chemical imbalances in the blood.
The type and location of a cancer is important in determining treatment. Many breast cancers are small and curable when detected. Very early cancers of the voice box (larynx) are 99% curable. Some cancers are ‘silent’ until they are advanced and are more difficult to cure. The outcome of one patient with breast or prostate cancer, etc does not predict the outcome of another person with that same cancer. While general statements in books or on websites can be helpful, they are no substitute for a face-to-face consultation with a specialist.
Article courtesy of Arizona Breast Cancer Specialists.