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What is cancer?
Cancer is a disease of the body's cells. Normally cells grow and multiply in a controlled way, however, if something causes a mistake to occur in the cells' genetic blueprints, this control can be lost. Cancer is the term used to describe collections of these cells, growing and potentially spreading within the body. As cancerous cells can arise from almost any type of tissue cell, cancer actually refers to about 100 different diseases.
Cancer cells that do not spread beyond the immediate area in which they arise are said to be benign ie. they are not dangerous. If these cells spread into surrounding areas, or to different parts of the body, they are known as malignant - commonly referred to as cancer.
How does cancer develop and spread?
As mutant cells (those with mistakes in their genetic blueprint) grow and divide, a mass of abnormal cells or a tumour is formed. In some cases these cells will form a discrete lump, in other cases such as leukaemia, abnormal blood cells circulate around the body.
Cancer cells can break away from the mass (or tumour) and travel via the bloodstream or lymphatic system to different parts of the body. These cells can settle in other parts of the body to form a secondary cancer or metastasis. Cancer can cause premature death because these secondary cancers stop parts of the body from working properly.
What causes cancer?
We do not know all of the risks and causes of cancer. However, there are a number of chemical, physical and biological agents that have been shown to trigger the mistakes in the cell blueprint that cause cancer. These are called carcinogens and include tobacco, ultraviolet radiation and asbestos.
A number of cancers share risk factors:
- one in nine cancers, and one in five cancer deaths, are due to smoking
- about 1.9 - 5.8% of cancers are related to alcohol consumption
- many cancers occur as a direct result of dietary influences,
- from infectious agents or exposure to radiation (especially skin cancers from ultraviolet radiation)
- some cancers result from inherited ‘faulty’ genes
- cancer is NOT caused by injury or stress.
How many Australians get cancer?
Cancer is a common disease and a major health problem in Australia today. At current rates, it is expected 1 in 2 Australian men and 1 in 3 Australian women will be diagnosed with cancer by the age of 85.
An estimated 128,000 new cases of cancer will be diagnosed in Australia this year.
Cancer is a leading cause of death in Australia – more than 43,200 people died from cancer in 2011.
Around 19,000 more people die each year from cancer than 30 years ago, this is due mainly to population growth and aging. However, the death rate (number of deaths per 100,000 people) has fallen by more than 16%.
More than 60% of people diagnosed with cancer in Australia will survive more than five years after diagnosis.
The survival rate for many common cancers has increased by 30 per cent in the past two decades.
What are the most common cancers?
The most commonly diagnosed cancer (excluding non-melanoma skin cancer) is prostate cancer, followed by colorectal or bowel cancer, then breast, melanoma and lung cancer. There are more than 100 different types of cancer, but these five most common types account for 60% of all cases.
The most common cancers for men and women are listed in order below:
Which cancers cause the most deaths?
Cancer is a leading cause of death in Australia – more than 43,200 people died from cancer in 2011. The most common causes of cancer deaths are not necessarily the most frequently occurring cancers. While lung cancer is the fifth most common type of cancer overall, it is the leading cause of cancer death in Australians.
The most common cause of cancer related death in men and women are listed in order below:
Who gets cancer?
Anybody can develop cancer. 1 in 2 Australians will be diagnosed with cancer by the age of 85.
The risk of cancer increases with age - more that four times as many cancers are diagnosed in people over 60 years, as in those under 60. However, increased awareness about cancer, screening programs and early detection means that cancer is increasingly diagnosed in younger people - which means it is often at an earlier stage and can be treated more effectively.
Can cancer be prevented?
With our current knowledge, we believe that at least one in three cancer cases can be prevented. Smoking, sun exposure, poor diet, alcohol consumption and inadequate physical activity are significant risk factors, which can be modified.
Not smoking, or giving up, is the single most effective strategy to prevent cancer. One in nine cancer cases, and more than one in five cancer deaths (over 7700 every year) are caused by cigarette smoking.
Protecting your skin from exposure to the sun's UV radiation is a simple and very effective strategy for preventing skin cancer. More than 11,400 Australian men and women are diagnosed with a melanoma each year, and an estimated 434,000 people are treated for one or more non-melanoma skin cancers. In 2011 there were more than 2000 deaths from melanoma and non-melanoma skin cancer. Relative five-year survival rates for melanoma are 90% for men and 95% for women.
It is estimated more than 4000 cancer deaths annually are due to poor diet, alcohol consumption, physical inactivity and being overweight. Again these are deaths that can be prevented. See our preventing cancer section for more information on how you can reduce your cancer risk.
Is cancer contagious?
Cancer is not contagious. There is no reason to avoid people with cancer, and in fact they will need your support and understanding.
We now know that some cancer genes are hereditary and so several family members may have the same or related types of cancer. This is due to an inherited genetic disorder, not spending time together.
Human papilloma virus (HPV), a virus that causes 70% of cervical cancer, is contagious and is transmitted via sexual activity. However, cervical cancer itself is not contagious.
Does cancer always cause pain?
Some cancers cause pain, others do not. Some people experience pain as the result of tumour growth or advanced cancer, or as a side effect of treatment.
Pain relief is always made available to cancer patients suffering pain. Your doctor can advise you on what to expect and how the pain can be managed.
Is cancer always fatal?
Absolutely not. Advances in our knowledge about prevention, early detection and treatment mean that over 60% of people diagnosed with cancer today can be effectively treated. Almost nine out of 10 children with cancer are effectively treated and go on to live normal lives.
As we further our knowledge about the disease, survival rates are likely to increase. Your state or territory Cancer Council can provide further information and support for cancer survivors and people living with cancer.
Why do we have screening programs for some cancers?
Screening involves testing people who have no symptoms for the presence of early, potentially curable disease. At present national screening programs exist for breast cancer, cervical cancer and bowel cancer.
There is no national screening program from prostate cancer. Current evidence shows that the harms of population screening with the prostate specific antigen (PSA) test outweigh the benefits. Therefore, either alone or combined with digital rectal examination, the PSA test does not form the basis of a population-based screening program.
What tests should I have?
Women should have a Pap test every two years, which will check for cervical cancer.
Also be on the lookout for any changes to your breasts; if you notice any lumps or other changes, talk to your doctor as soon as possible. If you are over 40 you are eligible for a free mammography screening every two years. We strongly recommend you are screened regularly if you are aged 50-74.
If you turn 50, 55 or 65 this year, you will be invited to participate in the National Bowel Cancer Screening Program. From 1 July 2013, people turning 60 were included; people turning 70 will be added in 2015.
Cancer Council Australia recommends anyone interested in testing for cancer speak with their GP.
For more information on national screening programs visit the Federal Government’s cancer screening website.
How is cancer treated?
The type of cancer treatment or combination of treatments that a patient has depends on the type and stage of the cancer. The most common types of cancer treatment are surgery, chemotherapy and radiation therapy.
Some cancers can be cured if the tumour is detected and surgically removed before the cancer cells spread. Chemotherapy (anti-cancer drugs) and radiotherapy (radiation treatment) can also cure cancer, by killing cancer cells or stopping them from multiplying. Often these treatments are most effective when used together.
The main goal of treatment is to cure the disease, but if cure is not possible, different treatments may be used to control the cancer. New ways of treating cancer are always being developed and tested. In the future, we can expect to see a new range of 'designer drugs' which can block the blood supply that tumours need to grow, correct the genetic defects that lead to cancer and assist the body's immune system to fight cancer.
What about treatment side-effects?
Usually when you suffer a disease you feel symptoms such as pain and the treatment makes you feel better. Unfortunately with some cancers, you may not have experienced any pain or discomfort until the treatment begins.
Cancer treatments designed to kill cancer cells can have unpleasant side-effects, such as nausea and vomiting, bowel problems, tiredness, hair loss and scalp problems and effects on nerves and muscles.
Before beginning treatment it is best to be aware of the possible side-effects and changes that your body may go through, and ways of managing or reducing them.
How do I decide about treatment?
Sometimes, making decisions about your treatment can be very hard. It may be even harder when you know that the treatment is aimed at relieving and controlling symptoms rather than curing the cancer.
Once you have discussed treatment options with your doctor, you may want to talk them over with your family or friends, nursing staff, the hospital social worker or chaplain, or your spiritual advisor. Talking it over can help you to sort out what course of action is right for you. In most cases it is safe to delay treatment a few days or a week or so, but you should not put it off longer.
Should I take part in clinical trials?
Your doctor may suggest that you take part in a clinical trial. Clinical trials are an essential part of the quest to find better treatments for cancer.
Doctors conduct clinical trials to test new or modified treatments and see if they are more effective than existing treatments. Hundreds of thousands of people all over the world have taken part in clinical trials that have resulted in many improvements to cancer treatment. All trials are approved by an Ethics Committee.
To help you make an informed decision about joining a clinical trial, your doctor will discuss the trial and its implications for you. If you join a 'double blind' clinical trial, you will be given either the best existing treatment for your condition or a promising new treatment. Treatments are randomly assigned, so neither you nor your doctor knows which treatment you are being given.
If you do join a clinical trial, you have the right to withdraw at any time. Doing so will not jeopardise your cancer treatment.
What about complementary therapies?
Many people with cancer consider complementary therapies in addition to treatment recommended by their doctors.
Complementary therapies are supportive therapies used to complement mainstream treatments. These are often recommended by your doctor or another health professional, not to cure disease, but help control symptoms and improve well-being. Examples include massage therapy, yoga, meditation, herbal teas and acupuncture.
If you are using, or considering, a complementary therapy, discuss it with your doctor or call Cancer Council Helpline for advice.
What about alternative treatments?
There are many "alternative therapies" that are promoted as cancer cures. They are unproven because they have not been scientifically tested, or were tested and found to be ineffective. If alternative therapies are used instead of evidence-based treatment, the patient may suffer, either from lack of helpful treatment or because the alternative treatment is actually harmful.
If you are thinking about using a treatment which is not an evidence-based medical treatment, make sure you carefully consider and investigate the claims being made. Look into the evidence for those claims, the credentials of the people or organisation promoting the treatment, the costs and the potential risks of delaying conventional treatments.
The American Cancer Society recommends the following checklist to spot treatments that might be open to question:
- Is the treatment based on an unproven theory?
- Does the treatment promise a cure for all cancers?
- Are you told not to use conventional medical treatment?
- Is the treatment or drug a "secret" that only certain providers can give?
- Does the treatment require you to travel to another country?
- Do the promoters attack the medical/scientific establishment?
If the answer to any of these questions is 'yes', you should carefully consider whether the proposed treatment is of any value.
Cancer Council Australia urges people with cancer to remain in the care of qualified doctors who use proven methods of treatment and participate in clinical trials of promising new treatments. If you are using, or considering, an alternative treatment, discuss it with your doctor or call Cancer Council Helpline for advice.
- Australian Institute of Health and Welfare 2014. ACIM (Australian Cancer Incidence and Mortality) books. Canberra: AIHW. Available from: http://www.aihw.gov.au/acim-books/.
- Australian Institute of Health and Welfare & Australasian Association of Cancer Registries 2012. Cancer in Australia: an overview, 2012. Cancer series no. 74. Cat. no. CAN 70. Canberra: AIHW.
- Australian Institute of Health and Welfare 2012. Cancer incidence projections: Australia, 2011 to 2020. Cancer Series no. 66. Cat. No. CAN 62. Canberra: AIHW.
- National Cancer Control Initiative 2003. The 2002 National Non-melanoma Skin Cancer Survey. Melbourne.
This page was last updated on: Tuesday, March 25, 2014