Prostate Cancer Canada Network

In The News

Well-Done Meat Consumption May Increase Prostate Cancer Risk
Research into the dietary habits of about a thousand men from the Cleveland area has found that a high consumption of meats, especially of red meat prepared by grilling, is positively associated with an increased risk of developing aggressive prostate cancer. This particular study, which was led by Dr. John Witte of the University of California, San Francisco (UCSF), has a number of limitations, but it does add support to other investigations connecting meat consumption with cancer risk.

Toronto researchers speculate regarding a link between prostate cancer and oral contraceptive use
Very preliminary and speculative research, designed to spark further inquires, suggests that there may be a connection between oral contraceptive use and rising rates of prostate cancer. One theory is that the widespread use of birth-control pills in various populations may result in a higher level of estrogen in the environment, which might, in turn, increase prostate cancer risk.

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What is Prostate Cancer

To understand prostate cancer, we need to understand cancer because prostate cancer is cancer that starts in the prostate gland. So what is cancer? Cancer is a disease of our cells. The human body is made up of billions of cells, each one controlled by genetic material (genes) contained within the cells themselves. Over time, we are exposed to many things that damage our genes (our DNA), things such as radiation, chemicals in the environment, or viruses. Our bodies can repair genetic damage, but, sometimes, this damage overwhelms repair mechanisms or slips by them, and cancer is the result. Cancerous cells are cells that are out of control. They have three main characteristics:

A cancerous cell's natural process of growth and death is uncontrolled
A cancerous cell has lost its normal structure and, consequently, its ability to function as it should
A cancerous cell can escape the area in which it first grew and invade other parts of the body

To simplify, cancer is a disease of the genes; it means that our genes are no longer in control of the growth, the structure, or the location of some of our cells. Let's look at these three characteristic of cancer more closely.

Uncontrolled growth

When damage occurs to our DNA, abnormal cells may begin to appear and to reproduce and grow in an uncontrolled way. These abnormal cells can group together to form lumps or tumours.

Having a tumour, however, is not the same thing as having cancer. Tumours can be benign, which means that the cells of the tumour stay in one place in our bodies. Benign tumours are usually not life threatening, but, because they squeeze nearby parts of the body, they can be painful and interfere with the body's normal functioning.

Cancer cells, because they do not die as they should, grow exponentially. In other words, one cell becomes two, two cells become four, four cells become eight, and so forth. Different types of cancer grow at different average speeds, however, and doctors sometimes talk about tumour doubling time or the average time it takes a particular cancer to double in size. Also, even though prostate cancer may have an average tumour doubling time of between two to four years, there is considerable variation. Some prostate cancers grow faster (and have a shorter doubling time) and some grow slower (and have a longer doubling time). See information on the clinical staging and grading of prostate cancer.

Abnormal structure

When normal cells reproduce and grow, they become specialized and able to perform particular functions in the body. Some cells may work together, for example, to form organs such as the prostate or the kidneys. This process of specialization is called differentiation; cells with different jobs look different and develop differently from one another. Differentiation is the reason a kidney cell can't behave like a prostate cell, for example. It follows that new, normal prostate cells will look and function like other prostate cells. Prostate cancer cells, however, especially rapidly growing ones, become progressively less differentiated; they look less and less like a normal cell from the prostate. And the less differentiated the cells are the more they loose their ability to perform any useful job. Sometimes, cancer cells are so abnormal that it is difficult to tell what they were originally supposed to be or do. These cancer cells are called "poorly differentiated," and they are usually fast growing and dangerous.

Invasive
The defining characteristic of a cancer cell is that it can invade other parts of the body. Remember, abnormal cells can form benign tumours that are not cancer. Cancer, by definition, can spread.

Sometimes, prostate cancer spreads by breaking out of the prostate and into nearby areas, such as the seminal vesicle. Alternatively, cancer can travel to other parts of the body through the blood or the lymph.

Most people know something about blood and about the capillaries, vessels, and arteries that make up the human circulatory system, but few know much about lymph and the lymphatic system. Lymph is a nearly clear fluid that contains a high number of lymphocytes or white blood cells. These fight infection and destroy waste from dead cells. The lymphatic system consists mainly of three things:

lymph vessels, which carry the lymph around the body;
lymph nodes, which are basically small swellings of tissue along a lymph vessel and which contain huge numbers of white blood cells; and
other body organs such as the spleen, the thymus, the adenoids, and the tonsils.

One function of the lymph nodes is to swallow up and kill unwanted substances, such as germs. Because of this function and because of the lymphatic system's job of carrying food to cells and helping to eliminate waste from cells, lymph nodes sometimes contain cancerous cells. A lymph node that contains cancerous cells is called "positive," and it is usually bigger than normal. The more it is affected by cancer, the bigger it will be.

Having a basic idea of what cancer is will help you understand how medical professionals describe prostate cancer. Now you will be able to decipher the staging and grading systems that doctors use to analyse each case of prostate cancer and to decide on possible treatments.

For information on how common prostate cancer is, click here.