What is Cancer? Section 2 - What Is Cancer? - 1 -

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What is Cancer?

Normal Growth

The human body is made up of many millions of tiny building blocks called cells. Each organ of the body (eg. brain, liver,

muscle) contains its own special types of cells, each type having a special function (eg. muscle cells can shorten to move a joint, nerve cells send electrical impulses to each other and to muscle cells).

Every cell has a central part called the nucleus, which contains the genetic material, which we inherit from our parents. The nucleus is like the managing director of a factory and the surrounding gel, or cytoplasm, which makes up the rest of the cell, is the shop floor, where the orders are carried out.

All the information that is needed to make a human being is contained in the nucleus of every cell, in a long molecule called deoxyribonucleic acid or DNA for short. For ease of handling, this DNA is divided up into structures called chromosomes, of which humans have 46, 23 from each parent. (Think of them as the board of directors!)

The DNA in each chromosome reads like a book; some sections, or genes, give specific orders on how to make proteins, while other sections are involved in controlling which genes are read in that particular cell.

When a human is still a tiny embryo inside its mother it is made up of only a handful of cells. All of these cells can divide and multiply and gradually become more specialised until they form structures such as bone, heart, etc in the still quite small embryo. Thereafter, each cell simply divides and produces more of its own kind in a controlled way until the baby is ready to be born.

The process doesn’t stop there, however, and most cells in our bodies go on dividing and multiplying throughout our lives to replace old cells damaged through wear and tear or injury. Some cells can do this very quickly (eg. skin and bone marrow), others only very slowly, if at all (nerve and muscle cells). You can see that the making of a human being is very complex and it is no

surprising that things can go wrong from time to time.


Cancer Growth

Cancer is what happens when just one cell in the body, for some as yet unknown reason, starts to divide and multiply without the normal controls. All cancer cells develop abnormal genetic structure as they grow outside the normal body controls. The abnormal genes tell the cell to grow, divide and multiply. From one cell comes many thousands or millions of cells.

At first the person won’t feel anything, but when enough cancer cells have built up, there may be a lump, ‘growth’ or tumour as it is sometimes called. Not all cancers produce a lump; some types of cancer cells spread all round the body very early in the course of the disease and invade or ‘infiltrate’ other organs, eg. leukaemia and lymphoma cells can go into glands, kidneys, bones, the brain, eyes and even skin.

Cancer is not one disease, but more than a hundred different diseases, each with its own pattern of behaviour, response to treatment and outcome.

Leukaemia, lymphoma, brain tumour, neuroblastoma, rhabdomyosarcoma, osteosarcoma, Ewing’s sarcoma and Wilms’ tumour are just some of the more common types of cancer in children.

Relative incidence of different types of childhood cancer

a. Leukaemia b. Brain tumours c. Wilms' tumour d. Other tumours e. Non-Hodgkins lymphoma f. Neuroblastoma g. Rhabdomyosarcoma h. Hodgkins disease i. Retinoblastoma j. Osteogenic sarcoma k. Germ cell tumours 1. Ewing's sarcoma m. Histiocytosis X (The exact figure is not known and this is an estimate.)


Childhood cancers are rare affecting approximately one in ten thousand children per year. With few exceptions, there is no major risk of other children in the same family developing the same cancer.

In South Australia we see between 50 to 60 children diagnosed with cancer.

What causes cancer?

The causes of cancer are largely unknown, but medical research is increasing our knowledge of cancer and has given us some clues about the causes. The current theory is that we all inherit

important growth controlling genes. These genes can either start or stop cell growth, and cancer may develop when these genes are wrongly started or stopped. This happens when mistakes are made in copying the growth controlling genes, or when these genes are directly damaged. Parents usually find it helpful to talk to their doctor about the causes of cancer.

Is cancer preventable?

Since the causes of cancer in children are not yet known, there is little that can be done at the present time to prevent childhood cancer.

Cancer is not contagious. There is, therefore, no risk of one child passing his/her tumour on to another.

There is no evidence that cancer can occur following a knock or injury.

Your child’s illness is not caused through something he or she did or did not do.

How do cancers come to be noticed?

Nobody knows when a cancer really begins, but there is always a period of time before the disease becomes obvious. During this time, the cancer slowly increases in size and then causes

symptoms, such as a lump. In leukaemia, early symptoms can be vague and will often mimic other less serious disorders.


Is cancer curable?

The goal of treatment for most tumours in childhood is cure, though this aim is not always achieved. There are still many unanswered questions about cancer, which prevent doctors from making accurate predictions about outcomes for individuals with cancer. Since the outlook for many children with cancer is good, treatment is almost always started with the intent to cure. Cures can involve long periods of drug treatment and sometimes operations and radiotherapy.

There may be times when you question is this treatment the right option. It is important to discuss this with your doctor, as there may be alternatives.

The first goal in treatment is to achieve a complete remission, and this usually takes a few weeks to months to achieve.

Remission means that the cancer is no longer seen by the usual tests. When this happens we know that the treatment has killed nearly all the cancer cells in the body. It is likely there are some cancer cells left a number too small to be seen by any of the tests available at this time. It does not mean that the child has been cured, although it is a step on the road to cure.

To pass from the stage of complete remission to cure, it is usually necessary to give further treatments over many weeks or months to kill the remaining cancer cells that are not seen by our tests.

Experience in treating cancer has taught doctors the different lengths of time are needed to treat different types of childhood cancer. The length of time required for your child’s treatment and the follow-up that is that is needed after treatment will be

discussed by your child’s doctor. It can take a number of years before we can safely say your child is cured and your doctor will discuss this further with you.

A relapse is the term used when a check of the child and/or tests shows that the cancer has returned. The situation is a sad setback but it is not always fatal. It usually means a different approach to treating the cancer must be planned, since some of the cancer cells have become resistant to the earlier treatment and begun to multiply in an uncontrolled way again.


The Media and Cancer

Advances in treatment occur so rapidly that textbooks and many articles about specific types of cancer are out of date within a year or two of their publication. It is not possible to update information on all types of cancer in an easily understood publication for parents and we realise the lack of available information can be frustrating.

In the resource section we have listed books, videos, CD -ROMS and quality web-sites that may be of interest to you.

There are frequently articles in the daily press about ‘new cancer breakthroughs’. It is important not to believe everything you might read about your child’s cancer in public library books or

encyclopaedias, or on the Internet, as the information may well be out of date or not relevant.

We encourage you to ask questions about information you may see in the media about ‘new cancer breakthroughs’. This

information is often taken from medical journals or by interviews with leaders in cancer treatment and research. How this is applied to day-to-day cancer medicine may have been distorted. Discuss these issues with your doctor and bring the media article with you for the staff to read.

The Internet

There is a large amount of information available on the Internet.

Keep these questions in mind when you are looking at information:

• Is the information up to date and accurate. Information should be referenced with authors names and date of publication.

• Does it come from a reliable source? There should be a list of editorial staff and credentials of the people behind the


• Who stands behind the information, some information may be biased to promote a particular product.

• How patient oriented is the site.

• Price of the information, very few medical websites charge for information.

Please discuss any of the information you find with your doctor to check if it is relevant to your child.


Web sites Related to Cancer.

The web sites listed contain information that you may find helpful, there are many more site that have not been included. Please remember that it is important to discuss any information you may find on web sites with your treating doctor to check if it is relevant to your child.

Disease Information:

www.cancerbacup.org.uk – Welcome to Cancer Bacup

www.cancer.gov – National Cancer Institute – Cancer Information http://www.nih.gov – NIH – Health Information

www.royalmarsden.org – The Royal Marsden Hospital www.stjude.org – St Jude’s Children’s Research Hospital www.acor.org – Types of Cancer

www.oncolink.upenn.edu/ - Oncolink - types of cancer www.rch.unimelb.edu.au/haem_oncology/ - Women’s and Children’s Health

www.cancersa.org.au – Cancer Council of SA www.leukaemia.com – Leukaemia Foundation

www.cancerindex.org/ - About Cancer – Guide to Internet Resources for Cancer

www.sch.edu.au/ - Sydney Children’s Hospital

www.health.adelaide.edu.au/paed-neuro/index.htm – Women’s and Children’s Hospital - neurosurgery

www.outlook.life.org - Outlook Portal

http://is.dal.ca/~pedpain/ Paediatric Pain management

Children’s Sites

www.cancerkids.com – Children Learn about Cancer www.kidswithcancer.com/ - Kids with Cancer

www.kidscope.org/ - Kids Cope Frames

www.cancersourcekids.com – a World of Understanding for Children and Parents

www.royalmarsden.org.uk/captchemo/adventures.asp for 9-


Support Groups

www.campquality.org.au – Camp Quality

www.makeawish.org.au – Make a Wish Foundation

www.childhoodcancer.asn.au – Childhood Cancer Association www.cancersa.org.au - Cancer Council SA


The Treatment Plan

By the time your child reaches the Oncology Unit, the diagnosis of cancer is either strongly suspected or has been made. Before treatment can commence, a number of tests are required, and these tests vary from one cancer to the next. Once the diagnosis has been made and the extent of disease shown by the various tests and procedures, the oncology team will discuss these results and the treatment options with you in great detail. With your permission, they will also be explained to your child in terms suitable for the child’s age.

The treatment plan (protocol) is a set of guidelines for treatment including when and what types of drugs are given and when tests are done. There are several stages in the protocol and each of these will be explained to you. At each visit, you and your child will be told what will happen at the next visit and in the time between visits.

Tests to monitor the progress of your child’s cancer will be done in line with the treatment protocol. Before these tests occur you will be given information about the test and any special instructions.

During the first few days you will receive a lot of information and we know that it is hard to remember and understand all this in a short space of time.

There will be many opportunities for you to ask questions and make clear aspects of your child’s illness and treatment protocol so please write your questions on paper as you think of them, so that they may be discussed with staff.

Understanding what is happening is like learning a completely new language and this can be overwhelming, but staff are always available to help you and we welcome your questions.

The intensity and frequency of visits will vary with each individual protocol. The length of treatment will vary depending on your child’s disease and your doctor will discuss this with you.




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