Cancer (Overview)
Overview
The word "cancer" refers to abnormal cells that
grow uncontrollably. Cancer is not a single disease.
It can involve any type of cell, anywhere in your
body. And it starts with a problem in the cell's
genes.
Damaged Cells
All cells contain genes that control how they grow,
divide and eventually die. But these genetic
instructions can become damaged. For example,
too much sunlight damages genes in skin cells.
Cigarette smoke damages genes in lung cells. In
most other cases, the exact cause of the damage is
not known.
Uncontrolled Growth
When its genes are damaged, a cell may grow
uncontrollably. The abnormal cell may live beyond
its normal lifespan, dividing again and again. And
the new cells it produces inherit the damaged
genes. When these cells grow into a mass without
invading healthy tissues, this is called a "benign"
growth. Benign cells are not cancer. But when
abnormal cells grow uncontrollably and also invade
healthy tissues, they are called "malignant," and
"cancerous." This is cancer.
How Cancer Spreads
Cancer cells can form lumps of abnormal cells
called "tumors." Cancer cells can also spread to
other parts of the body, commonly through the
bloodstream or the lymphatic system. For example,
cancer cells that form in the colon may spread to
the liver or the lungs. When cancer cells spread
from one part of the body to another, the cancer is
said to have "metastasized."
Treatment
Different types of cancer can behave very
differently. There isn't just one way to treat cancer.
Your doctor can explain the pros and cons of
treatment options such as surgery, chemotherapy
and radiation therapy. Your healthcare team will
work with you to develop a care plan that is right for
your needs.