I’ve noticed that when I’m giving a talk to an audience of cancer patients, advocates, or family, some of the most common questions I am asked are often about “the basics.” That is, the simplest background questions about the “how” and “why” of cancer. I speculate that some times we are so focused on the management of the patient’s cancer, we don’t spend as much time answering the basic questions.
I thought I’d share my version of a cancer “lecture series,” attempting to answer these questions. I’ll focus on the simplest explanations I can manage. As cancer is such a complex and varied disorder, I will definitely oversimplify from a scientific standpoint; however, I think it makes it easier to understand.
So the most common questions I hear:
- What is cancer?
- What do I have?
- Why do I have it?
- What is my stage (where is it)?
- How advanced is it?
- How aggressive is it?
- What is the treatment?
- What are my chances?
When people ask my advice about what to ask an oncologist when they find out they have a cancer diagnosis, I usually tell them that this set of questions is a pretty good starting point- I tell people to write down the list and take it with you!
So, to start: What is cancer?
Cancer is a disease where cells derived from normal tissues lose their normal regulation, function, and behavior, and have the ability to reproduce, grow and spread
- i.e. the control mechanism for the tissues that cancers come from is “broken”!
Our bodies are made of of cells- lots of them. The best estimate I’ve read is 37 trillion (yes, with a T) cells. These cells form the building blocks of all our organs and tissues.
Most cells in the human body follow a set “program.” Our cells are generally good citizens, performing the basic functions of the human body in an organized and coordinated fashion. They work together, as a team, to allow our bodies to work in a healthy fashion.
Each cell in our body knows exactly when to divide (i.e. to grow and reproduce), where to live, what to do, and when to die. So your heart muscle cells know that they belong in the heart, that they are specialized to contract (i.e. help pump blood). Your colon gland cells know that they live in the colon, that their job is to produce mucous and absorb fluid, know to replace themselves when needed, and know when they have worn out and need to die off. You won’t find a colon gland cell in the heart, and you won’t find a heart cell in the colon.
Cancers don’t follow these rules. They are the juvenile delinquents of the cell world. Instead of growing only when told, they grow uncontrollably. Instead of dying off when they have outgrown their function, they become “immortal.” Instead of performing their planned function, they don’t contribute anything helpful or do their job. And most importantly, they invade. They don’t stay put where they are supposed to. They grow through tissues and spread to other parts of the body. Many would say that it is this behavior of invasion that makes a cancer a cancer.
That is what makes the difference between a benign and malignant (or cancerous) tumor. The word "tumor" itself just means “a growth.” So a mole or freckle could technically be called a tumor, as could any number of benign growths that many humans have. It’s the invasion that makes it cancer.
Most cancers do not just pop up overnight- they develop over time, probably years and years. What we think happens is the following:
Come back next week for the next post:
What causes this to happen?