Understanding Cancer

The physiological cause of cancer is excessive cell growth and nutrient use due to damage to the cells DNA.  The symptoms of cancer are numerous and can include; a change in bowel or bladder habits, a lump or thickening in any body tissue and /or any changes in neurological function.

What is cancer?

Cancer is a class of diseases or disorders characterized by the uncontrolled division of cells and the ability of these cells to spread, either by direct growth into adjacent tissue through invasion, or by implantation into distant sites by metastasis (where cancer cells are transported through the bloodstream or lymphatic system). Cancer may affect people at all ages, but its risk tends to increase with age. It is one of the principal causes of death in developed countries.

Types of cancer

There are more than 100 types of cancer. Cancers can be grouped into three main categories:

• Carcinomas - which occur in the lining of the body's external and internal surfaces, e.g. the skin, mouth and rectum
• Sarcomas - which form in connective tissues, e.g. muscles and bones
• Leukaemias and lymphomas - these are cancers of the bone marrow and lymph glands. These types of cancers don’t necessarily cause tumours

The severity of symptoms depends on the site and character of the cancer and whether there is metastasis. Most cancers can be treated and some cured, depending on the specific type, location, and stage.

Once diagnosed, cancer is usually treated with a combination of surgery, chemotherapy and radiotherapy. If untreated, cancers may eventually cause illness and death, though this is not always the case.  Even if the cancer cannot be cured, people often live for some time after treatment.

Many mutation events may be required to transform a normal cell into a malignant cell. These mutations can be caused by radiation, chemicals, free radicals or physical agents that cause cancer, which are called carcinogens, or by certain viruses that can insert their DNA into the human genome. Mutations occur spontaneously, and may be passed down from one cell generation to the next as a result of mutations within germ lines (germ lines are cells that carry genetic information that can be passed from cell to cell and from generation to generation - father to son.)

Free radicals are cells that have lost an electron, thus are unstable cells. These free radicals basically steal electrons from other cells in an effort to heal (balance) themselves, ultimately creating new free radicals in the process. By stealing electrons, free radicals can cause damage to our DNA, leading to the possible development of cancer. The free radical cells are caused by carcinogens such as sun exposure and smoking.

Antioxidants search for these free radicals and lend them an electron. This stabilizes the molecule, thus preventing damage to other cells. Antioxidants also turn free radicals into waste by-products, and they eventually get eliminated from the body. They also have the ability to repair previous damage to cells.  So antioxidants are definately 'the good guys' in the cancer battle.

Where Can You Find Antioxidants?

Antioxidants are found naturally in fruits and vegetables. They also are contained in some meats. Some examples of fruits and vegetables that are rich in antioxidants are:

• Yellow, orange and red fruit and vegetables like sweet potatoes, carrots, pumpkin, red peppers, tomatoes, papaya, guava, and cantaloupe
• Green and leafy veggies, like turnip greens, spinach, broccoli, green peppers, bok choi and kale
• Other great fruits include strawberries, kiwifruit, cranberries, and plums

It is also important to remember that having a defective gene does not mean that you are definitely going to get cancer - it does however mean that you have a higher risk of developing cancer.

Many forms of cancer are associated with exposure to environmental factors such as tobacco smoke, radiation, alcohol, sun exposure and certain viruses. Some risk factors can be avoided or reduced.

How do cells work normally?

Our bodies consist of billions of cells. Our bodies are constantly making new cells; to enable us to grow, to replace worn-out cells, or to heal damaged cells after an injury. All our organs, bones, muscles, skin, blood and other fluids are made up of specialised cells.

Although each group of cells has different functions they all reproduce by dividing (replicating). In childhood the cells divide rapidly. Once a person reaches adulthood, the division of cells slows down. In some parts of the body, such as the brain, the division of cells stops completely.

Some other cells also stop growing, but if they are damaged new cells can grow to replace the lost ones. For example, kidney cells are able to grow when needed.  Other cells, such as blood, skin and hair are constantly being worn out and replaced.

How does cancer develop?

1.      A normal cell is exposed to enough carcinogens (cancer causing agents) such as the sun to mutate the cell. The unregulated growth that characterizes cancer is caused by damage to DNA, resulting in mutations to genes that control cell division.

2.      Now the cell has an abnormal nucleus (centre) and cell growth (splitting of cells) becomes uncontrolled. The growth is disorganized and the cells are no longer specialised (for example a muscle cell) and they no longer function.

3.      Due to cancer cells having no contact inhibition (see the following contact inhibition diagram), the cancer cell growth continues until a tumour (a lump made up of uncontrolled cells) develops which invades and destroys neighbouring tissue. Some cancers are more aggressive than others and will invade at a greater rate.

4.      Cancer cells are very active cells – they need lots of nutrients and therefore blood. Cancer cells develop more capillaries, increasing the blood supply to help “ feed” the tumour

5.      Tumours get large and metastasis occurs. This is where cancer cells break free and travel through the body in the blood stream and lymphatic system. They lodge and build secondary tumours.

Contact inhibition

• Normal cells - exhibit contact inhibition. This means they stop dividing when they come in contact with each other as can be see in this diagram.
• It also means normal cells cannot divide when isolated from one another. Cell communication is essential for cellular reproduction so if one cell broke off it would die.
• Cancer cells - do not have contact inhibition. They have lost all restraint and grow in multiple layers because of changes in their cell surfaces as can be seen in the diagram above.
• Caner cells also don’t need to stick to each other or to normal cells. If one breaks off it can continue to live and replicate. This is how metastasis is possible.

The following table summarises how cancer cells behave in comparison to normal cells:

Risk factors for Cancer

Having a risk factor for cancer means that a person is more likely to develop the disease at some point in their lives.  However, having one or more risk factors does not necessarily mean that a person will definitely get cancer.  Some people with one or more risk factors never develop the disease, while other people who do develop cancer have no apparent risk factors whatsoever.

Different kinds of cancer have different risk factors.  Some of the major risk factors include:

Modifiable risk factors

• Smoking alone causes one-third of all cancer deaths.
• Unprotected exposure to strong sunlight.
• Obesity
• Physical inactivity
• Poor diet (specifically a lack of fresh fruit and vegetables)
• High level of alcohol consumption

Non-modifiable risk factors

• Changes in hormones – for women this is linked to breast cancer

• Family health history - Genetics
• Age

Overall, environmental factors, defined broadly to include smoking, diet, and infectious diseases, as well as chemicals and radiation cause an estimated 75% of all cancer.  Among these factors, smoking, unhealthy diet, and physical inactivity are more likely to affect personal cancer risk.

Research shows that about one-third of all cancer deaths are related to dietary factors and a lack of physical activity in adulthood.

Certain cancers are related to viral infections and could be prevented with vaccines, others are linked to behaviour. More than 1 million of the skin cancers expected to be diagnosed in 2003 in America could have been prevented by protection from the sun's rays (putting on sunscreen).

Cancer  - Signs and Symptoms

Cancer gives you no symptoms or signs that exclusively indicate the disease.  Every complaint for cancer can be explained by a harmless condition as well.  If you have symptoms, however, you should see a doctor for further evaluation.  Some common symptoms that warrant further evaluation are as follows:

• Persistent cough or blood-tinged saliva

• A change in bowel habits
• Unexplained anaemia
• Breast lump or breast discharge
• Lumps in the testicles
• A change in urination (stops and starts, painful, changes in frequency)
• Blood in the urine
• Hoarseness (specifically hoarseness not caused by a respiratory infection, or that lasts longer than 3-4 weeks).
• Persistent lumps or swollen glands
• Obvious change in a wart or a mole
• Indigestion or difficulty swallowing
• Difficulty swallowing solids can be seen with cancer of the oesophagus.
• Unexpected weight loss, night sweats, or fever
• Non-healing sores
• Frequent headaches
• Back pain, pelvic pain, bloating, or indigestion 

Cancer Treatment

The three most common types of cancer treatment are surgery, radiotherapy and chemotherapy.  Treatment is aimed at removing the cancer cells or destroying them in the body with medicines or other agents.

Surgery

Surgery can be very successful in treating some kinds of cancer, but it isn't an option for all people.  If the cancer is in the form of a malignant tumour and the tumour is in one place (localized), it may be possible to safely "cut out" the tumour and any surrounding affected tissue.  Surgery may not be possible if the cancer has spread to other areas of the body or if the tumour cannot be removed without damaging vital organs, such as the liver or brain.

Radiotherapy

Radiotherapy uses radiation - in the form of a special kind of x-ray, gamma rays or electrons - to damage cancer cells so that they can't multiply.  There is usually no pain during therapy. Radiotherapy may sometimes be the only treatment needed, or it may be used with other therapies, such as surgery.  A combination of surgery and radiotherapy may be used for tumours that grow in one place.

Chemotherapy

Chemotherapy uses medicines to attack the cancer cells.  Just the word "chemotherapy" can cause a lot of fear because the side effects can be severe.  However, not all people experience severe side effects.  The side effects of chemotherapy can often be reduced with other medicines.

Chemotherapy is usually used when the cancer has spread to other areas in the body. Chemotherapy can also be used in combination with surgery and radiation. Sometimes the tumour is surgically removed and then chemotherapy is used to make sure all the cancer cells are killed.

Chemotherapeutic drugs work by impairing mitosis (cell division), effectively targeting fast-dividing cells (cancer cells).  As these drugs cause damage to cells they are termed cytotoxic.  Some drugs cause cells to undergo apoptosis (so-called "cell suicide").

Unfortunately, scientists have yet to be able to locate specific features of cancer cells that would make them uniquely targetable.  This means that other fast dividing cells such as those responsible for hair growth and for replacement of the intestinal epithelium (lining) are also affected (causing side effects such as hair loss and nausea).

As chemotherapy affects cell division, tumours with high growth fractions (such as leukaemia and lymphoma) are more sensitive to chemotherapy, as a larger proportion of the targeted cells are undergoing cell division at any time.

Drugs affect "younger" tumours more effectively, because mechanisms regulating cell growth are usually still preserved.  With succeeding generations of tumour cells, growth becomes less regulated, and tumours become less responsive to most chemotherapeutic agents.  Near the centre of some solid tumours, cell division has effectively ceased, making them insensitive to chemotherapy.

Other Treatments

Another kind of treatment is biological therapy. This treatment uses proteins to trigger the body's immune system to produce more white blood cells (or lymphocytes). Two lymphocytes that can attack and kill cancer cells are the T-cell and the B-cell. The proteins boost the ability of the T-cell and B-cell lymphocytes to kill cancer. Biological therapy can also be used in combination with surgery, radiation therapy or chemotherapy.

Hormone therapy is sometimes used to treat breast or prostate cancer.  The hormone oestrogen can make breast cancer tumours grow faster.  Similarly, the hormone testosterone can make cancerous tumours in the prostate grow faster.  Drugs that contain other hormones may be used to block the effects of oestrogen and testosterone.  In other cases, surgery to remove the ovaries or the testicles may be used.  Removing these organs reduces the amount of oestrogen or testosterone in the body.  Hormone therapy is often used in addition to chemotherapy or radiotherapy.

And lastly but by no means least, there is an increasing body of evidence supporting high dosage vitamin therapies to treat cancer, as an alternative to chemical, surgical and radiation interventions.  

The rationale behind high dosage vitamin therapies is very credible.  It involves removing as many cancer risk factors as possible (smoking, alcohol, high fat, high sugar fast foods), replacing these with healthy eating habits (lots of fresh fruit and vegetables), exercise and high dosage’s of injected vitamins, in particular vitamin c.

By doing this the supporters of high dose vitamin therapies believe that the environment for cancer to thrive in is eliminated and the body is supported to rid itself of cancer.  They do point out that the dosages need to be very high.  Many in the medical and pharmaceutical professions warn that high dosages of vitamins may be dangerous.  However the advocates of high dose vitamin therapies point out that there are very few (if any) cases of death associated with high dose vitamin intakes, whereas there are thousands of deaths every year directly attributable to adverse reactions from conventional medicines.