How cancer causes harm
Cancer harms the body in a number of ways. The size of the tumour, for example, can interfere with nearby organs or ducts that carry important chemicals, causing pain or other symptoms.
A tumour on the pancreas can grow to block the bile duct, leading to the patient developing obstructive jaundice. A brain tumour can push on important parts of the brain, causing blackouts, fits and other problems. Even benign tumours can cause these problems if located in the wrong place.
When a cancer invades nearby tissues, it can cause bleeding from damaged blood vessels, and stop the organ it is invading from working properly.
How cancer spreads
As a tumour grows, cells can break off and start growing on adjacent tissues and organs. For example, if bowel cancer has spread through the wall of the bowel itself, it can start growing on the bladder. Cells can also enter the bloodstream and travel to distant organs, such as the lungs or brain. The technical term for this is metastasis.
When new tumours form on distant organs, they behave like the original tumour - so a bowel cancer cell growing in the lung will not be lung cancer.
Once other organs are involved, any symptoms of the cancer can get worse. However, it may be some time before a growing cancer in certain parts of the body produces noticeable symptoms.
Once a cancer has started to spread beyond its original site, the chances of a cure often begin to fall, as it becomes more difficult to treat.
How cancer is treated
There are three principal ways of treating cancer.
The first is surgery, normally an operation to remove the cancerous growth and - depending on its type - nearby tissues and organs. A cancer patient may first undergo a minor operation called a biopsy to take a small sample of the cancer for analysis.
The surgeon will try to remove as much of the cancer as possible, but sometimes extra treatment will be needed. This could either take the form of radiotherapy or chemotherapy, or a combination.
While the overall number of new cancers is not falling, the good news is that successful treatment rates for many of the most common types are improving rapidly
Support for those with cancer
All patients treated with chemotherapy will be looked after by ateam of healthcare professionals, who are there to support you and access specialist support if required.
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