Cells gone Bad

Issue 77 February 2011

As part of World Cancer Day in February, Dr. Noreen A. Kassem investigates the word that has infected millions of lives across the globe.

Cancer is a word that has become an increasingly frequent and frightening fixture in our vocabulary. The increased rates of cancer are thought to occur because of changes in lifestyle, eating and exercise habits, environmental causes as well as increased life spans.

 However, though cancer has become a very common word, what it is and how it occurs remains little understood. Cancer is an umbrella term for a wide number of diseases that vary in occurrence, cause, progress, symptoms and treatment. In these diseases, abnormal cells divide and grow without natural order and control, leading to cancerous cells invading healthy ones and infecting tissues of the body. The cancer first affects the local area and can then spread throughout the body through the blood and lymph systems. 

 All cancers begin in the smallest unit of the body - the cells - causing them to grow at unnatural rates and even change the type of cells they are. When the orderly and organised process of cell growth and division is altered, the mutated cells can cause growths or tissue masses called a tumour.

 Not all tumors that develop in the body  are cancerous; benign tumours can be removed without reoccurring and do not spread to other parts of the body. Malignant tumors are cancerous and can invade nearby tissues and break away to spread cancer to other parts of the body in a disease process called metastasis. Additionally, not all cancers form tumours. Cancers such as leukemia cause abnormal cells that hinder the normal, healthy function of the body.
The risk for developing cancer for an individual can be dependent on various factors including genetic inheritance, lifestyle behaviours such as smoking as well as diet.

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Where Cancer Originates From

There are over 100 types of cancer. Most are defined by the organ or type of cell from which they originate. The main categories of cancer include:

Carcinoma

• These cancers begin in the skin and tissues that line and cover internal organs. For example, basal cell carcinoma occurs in the basal cells of the skin. 


Central Nervous System Cancers

• These are cancers that begin in the brain and spinal cord cells and tissues. 


Leukemia

• These types of cancer begin in the blood-forming tissues such as the bone marrow and result in a large number of abnormal cells, such as white blood cells to be released into the bloodstream.



Lymphoma and Myeloma


• These types of cancer begin in the cells of the immune system.


Sarcoma

• These diseases begin in the connective and supportive tissues such as the bone, cartilage, muscle, fat and blood vessels.

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Common Types of Cancer

Cancer Research UK lists cancer of the lungs, bowel, breast and prostate as causing approximately 47 percent of all cancer deaths in the UK. In total, cancer is responsible for approximately 30 percent of deaths in males and 25 percent in females.

Lung Cancer
Lung cancer is the most common type of cancer in both men and women. It now causes more cancer deaths in women than any other type of cancer, including breast cancer. This may be due to increased rates of smoking and exposure to second-hand smoke in women. Lung cancer accounts for more than one in five of all cancer deaths, with up to 90 percent of incidences linked to cigarette smoking as well as sheesha smoking.
There are two main types of primary lung cancer which begin in the lungs– small cell lung cancer and non-small cell lung cancer. Approximately one in five are small cell, while the rest are non-small. Both types differ in progress and treatment, with chemotherapy and radiotherapy usually used to treat small cell lung cancer, whilst surgery is also an option for non-small cell alongside the traditional treatment methods.

Bowel Cancer
Colorectal cancers or cancer of the bowel or intestines have increased in incidence in the UK. Bowel cancer includes cancers that begin in the large bowel, including the colon and rectum in the large intestine. Almost two-thirds of bowel cancers occur in the colon. Bowel cancers can also begin in the small intestine but this is quite rare. Bowel cancer is the most common in women after breast and lung cancers. It is also the most common in men after lung cancer and prostate cancer. Almost 80 percent of bowel cancers occur in people over the age of 60. Factors that increase the risk of bowel cancers include diet, healthy weight, exercise and genetics.

Breast Cancer
Incidences of breast cancer have increased and it remains the most common cause of death due to cancer in women aged 35-54.
Non-invasive breast cancer is found in the ducts of the breast and does not spread to areas outside of the breast. This type of breast cancer does not cause a lump and is usually only detected on a mammogram and with a biopsy. Invasive breast cancer has the ability to spread outside the breast and develops in the cells that line the breast ducts. This type accounts for almost 80 percent of all breast cancer cases.
25% of all breast cancer cases can be prevented by changing dietary habits. Research has shown that low fat diets have an association with lower risk of breast cancer, compared to high fat diets.
 
Prostate Cancer
Prostate cancer is one of the most common cancers, affecting 34,000 men across the UK. The early stage of prostate cancer only affects the prostate gland and has not spread to other parts of the body. Cancer that has spread to tissues around the prostate gland can be considered as locally advanced. When the cancer reaches the metastatic stage, it has already spread throughout the whole body and is thought of as being advanced stage. Prostate cancer commonly spreads to the spine, ribs, pelvis and thigh bone.

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