What is Cancer?

Cancer Occurrence

Cancer is diagnosed in more than 1 million people every year in the U.S. alone. Doctors currently estimate that 30-40% of us will get some form of cancer at some point in our lives, and this number will increase to about 50% in the next decade.

There are about 200 different types of cancer affecting the different body tissues, but there is no single cause for cancer. What affects one body tissue may not affect another. For example, tobacco smoke may cause lung cancer and over exposure to the sun could cause melanoma on your skin. But the sun won’t give you lung cancer and smoking won’t give you melanoma.

A ‘carcinogen’ is something that can help to cause cancer. For example, Tobacco smoke is a powerful carcinogen – but not everyone who smokes gets lung cancer. So there other factors are also involved. Some of the factors involved in getting cancer include:

  • Your age
  • Your genetics
  • Your immune system
  • Your diet
  • Your environment
  • Viruses
  • Cancer Cells

We all have billions of microscopic cells that are grouped together to make up the tissues and organs of our bodies. These ‘Normal’ cells grow in a controlled way and stop growing when they have matured. However, the DNA in some cells may become damaged, and when these ‘Cancer’ cells mature they continue to grow. By the time a cancer is big enough to detected as a lump or on a scan, there are billions of cells which continue to grow and may even begin to spread around the body (metastasize). Since there are many different types of cells in the body, and any of these can become cancerous. there are also many different types of cancer.


Tumors (lumps) can either be benign (not a cancer) or malignant (cancer):

Benign Tumors usually have a covering of normal cells, grow slowly, and do not spread to other parts of the body. They are made up of cells that are quite similar to normal cells, and will only cause a problem if they grow very large, become uncomfortable or unsightly, press on other body organs, take up space inside the skull, or release hormones that affect how the body functions.

Malignant Tumors are made up of cancer cells, usually grow quickly, destroying surrounding tissues, and may spread to other parts of the body.

Cancer Growth And Spread

For a cancer to grow it must have a good blood supply – just like any other growing body tissue. As a tumor grows in size, it damages the surrounding tissues, and it can also’Spread’ beyond its current location into other areas of the body.

Cancer cells use the blood stream and the circulation of tissue fluid (in the lymphatic system) to spread around the body. Doctors use a system called ‘Staging’ to describe the size of a tumor and whether it has spread. Many people will have their cancer diagnosed and successfully treated before it has spread. Some cancers are more likely to spread than others. And certain cancers are more likely to spread to particular parts of the body.

Primary And Secondary Cancers

The place where a cancer begins is called the ‘Primary Cancer’, but the cancer cells can be carried in the blood or lymphatic system to other parts of the body (metastasis), where they can start to grow new tumors. Cancers can also spread to nearby body tissues. For example, lung cancer can spread to the lining of the chest (the pleura), and ovarian cancer can spread to the lining of the abdomen (the peritoneum). Tumors from cancers that have spread are called ‘Secondary Cancers’. Doctors sometimes call these metastases and say a cancer that has spread or has ‘metastasized’.

Cancer Treatments

If you, or a friend or relative has recently been diagnosed with cancer, you will probably want to know more about the different cancer treatment options available:

  • Surgical cancer treatments directly remove the cancer
  • Radiation cancer treatments (Radiotherapy) use radiation to kill the cancer cells
  • Chemotherapy cancer treatments use drugs to kill the cancer cells

The right treatment for any individual depends on the type of cancer and the stage (size and spread), as well as their general state of health and any personal preferences that they may have.

Bone Marrow Transplants and Stem Cell Transplants now represent another option for some cancer patients. Originally used to treat leukaemias and lymphomas, bone marrow transplant or stem cell transplant can now be used to treat a variety of cancers. Treatments that can be given alone or in combination include:

  • Bone marrow or stem cell rescue
    High dose chemotherapy with bone marrow or stem cell rescue.