2. What is Cancer

In part 1 of we discussed that cancer describes the various types of conditions that relate to uncontrolled cell division. And so all cancers have this in common and they all begin in cells. When the natural process is disturbed the surplus of cells collect and form tumours, except for blood cancers.

It is the genes that control how cells behave. Damaged genes mean that cells may become cancerous. Each cell of your body contains DNA. In that long strand of DNA is an instruction telling cells how many times to divide. A cell will divide into two identical copies of itself and those new cells will in turn divide again. A cell continues to divide for around fifty times and then it dies and is washed out of the body through the lymphatic system, the blood, excrement or urine. Therefore cells are constantly being renewed in the body.

It is this instruction in the DNA, to stop dividing after a certain amount of divisions that when it becomes damaged is the cause of what we call a cancer. Without the instruction for a cell to stop dividing it would keep doing so indefinitely and overwhelm the body. So when there is a problem, think where all these additional cells will accumulate if none are dying and being washed out.

The type of cancer depends on which cells of the body are damaged. If smoking has damaged the DNA in your lungs then it is lung cancer. The mass of new cells multiplying in your body will move around looking for somewhere to settle. With Lymphomas, cells flow through the lymphatic system and collect in lymphnodes under the armpits, in the neck and groin areas, as well as the diaphragm. Blood cancers try to form but are flushed away.

Cells are so tiny that we can’t see them with the eye. The biggest cell in the world is the Ostrich egg which can be seen with the naked eye. Most DNA sits in the centre of the cell and contain genes and can’t be seen normally. Genes make proteins and in turn proteins make cells, such is the biological cycle of life.

In normal circumstances the lymphatic system’s lymphnodes are empty and when you are sick and white blood cells defend you, the dead cells end up in the lymphnodes. With children in particular you can feel the little lumps in their neck when they get sick. They are flushed away in in due course. When there is continuous cell division, dead cells look for space and overwhelm the lymphnodes.

A biopsy is often the first treatment to diagnose the type of cancer. A biopsy of a lymphnode tumour can reveal the presence of the Epstein-Barr virus and a consequent diagnosis of Hodgkin’s Lymphoma. So early diagnosis and treatment is always the priority when lumps present themselves.

Tumors are made of tissue from cells. In leukaemia cancer doesn’t form into tumours because it travels in the blood stream and prohibits the normal blood function by abnormal cell division amassing in the blood.

What are the cancer types

Cancers are divided into five groups according to the type of cell they start from. These are:

  • Carcinomas – cancer that begin in the skin or tissues that cover internal organs.
  • Lymphomas – cancer that begins in the cells of the immune system
  • Leukaemias – cancer that begins in blood forming tissue such as the bone marrow
  • Brain tumours – cancer that begins in the central nervous system
  • Sarcomas – cancer that begins in bone, cartilage, fat, muscle, or blood vessels

What causes cancer

Genetic changes may be:

  • Inherited from parents
  • Acquired during lifetime

Smoking
Tobacco is a carcinogen, i.e. capable of causing cancer, and 80 to 90 percent of lung cancer cases are caused by smoking. Even passive smoking greatly increases the chance of getting lung cancer.

Alcohol
Drinking increases the risk of getting alcohol assisted cancer, which most commonly appears in the head or neck, esophagus, liver, and breasts.

Obesity
Obesity is the second biggest cause of cancer in the UK.

Sun exposure
All forms of radiation can be very harmful and lead to skin cancer. You should not spend more than 20 minutes in the sun.

Unprotected sex
The HPV virus is the cause of virtually all of the 3,100 cervical cancer cases diagnosed in the UK every year. HPV can also cause other cancers; throat, mouth, genital areas. HIV among other sexually transmitted virus can increase the risk of cancer because HIV attacks the immune system making it easier for other viruses such as HPV.

In summary

Cancer harms the body when the part of a gene that controls the number of times a cell divides before dying is damaged. This causes cells to continue dividing and they form in areas where they accumulate into tumours. A tumour is simply a lot of cells bunched together.

Tumors can grow and interfere with the digestive, nervous, and circulatory systems, and they can release hormones that alter body function. Tumours are either benign or malignant.

A benign tumour does not spread to other tissues and cannot grow back after being removed. A malignant tumour is cancerous and can spread to other parts, and can grow back when removed. 

Malignant tumors form when one or both of the following things occur:

1) A cancerous cell moves around the body in the blood stream or the lymphatic system, and destroys healthy tissue in a process called invasion, which in general means it is feeding itself in order to continue dividing, a process called angio genesis that makes new blood vessels to feed itself.

2) A tumour spreads from its place of origin to other parts of the body and grows in a process known as metastasis. Unlike localised cancer, when a tumour metastasises, in particular to an organ such as the liver, it becomes a more serious condition and usually very difficult to treat.

For example, in the example mentioned above for lymphatic cancer, in particular Hodgkins Lymphoma, if the cancer remains localised to the lymphatic system then it will be diagnosed as anywhere up to stage 3b but if metastasised to the bone marrow then the diagnosis will be at stage 4. The treatment for both stages will be different and the latter a more aggressive one.