WHAT IS CANCER
Cancer causes cells to divide uncontrollably. This can result in tumors, damage to the immune system, and other impairment that can be fatal.
In the United States, an estimated 15.5 million people with a history of cancer were living as of January 1, 2016, according to a 2018 report from the American Cancer Society.
In this article, we examine types of cancer, how the disease develops, and the many treatments that help improve the quality of life and survival rates.
Some types of cancer cause rapid cell growth, while others cause cells to grow and divide at a slower rate.
Certain forms of cancer result in visible growths called tumors, while others, such as leukemia, do not.
Most of the body’s cells have specific functions and fixed lifespans. While it may sound like a bad thing, cell death is part of a natural and beneficial phenomenon called apoptosis.
A cell receives instructions to die so that the body can replace it with a newer cell that functions better. Cancerous cells lack the components that instruct them to stop dividing and to die.
As a result, they build up in the body, using oxygen and nutrients that would usually nourish other cells. Cancerous cells can form tumors, impair the immune system and cause other changes that prevent the body from functioning regularly.
Cancerous cells may appear in one area, then spread via the lymph nodes. These are clusters of immune cells located throughout the body.
Causes
For example, over 480,000 people die in the U.S. each year from smoking cigarettes, according to data reported in 2014.
In addition to smoking, risk factors for cancer include:
- heavy alcohol consumption
- excess body weight
- physical inactivity
- poor nutrition
Other causes of cancer are not preventable. Currently, the most significant unpreventable risk factor is age. According to the American Cancer Society, doctors in the U.S. diagnose 87 percent of cancer cases in people ages 50 years or older.
Is cancer genetic?
Genetic factors can contribute to the development of cancer.
A person’s genetic code tells their cells when to divide and expire. Changes in the genes can lead to faulty instructions, and cancer can result.
Genes also influence the cells’ production of proteins, and proteins carry many of the instructions for cellular growth and division.
Some genes change proteins that would usually repair damaged cells. This can lead to cancer. If a parent has these genes, they may pass on the altered instructions to their offspring.
Some genetic changes occur after birth, and factors such as smoking and sun exposure can increase the risk.
Other changes that can result in cancer take place in the chemical signals that determine how the body deploys, or “expresses” specific genes.
Finally, a person can inherit a predisposition for a type of cancer. A doctor may refer to this as having a hereditary cancer syndrome. Inherited genetic mutations significantly contribute to the development of 5–10 percent of cancer cases.
Treatments
Innovative research has fueled the development of new medications and treatment technologies.
Doctors usually prescribe treatments based on the type of cancer, its stage at diagnosis, and the person’s overall health.
