How cancer grows and spreads

This is called adjuvant therapy. The goal of adjuvant therapy is to help prevent the cancer from coming back in case some cancer cells are left behind in the body. In some cases, treatment may stop working become resistant so cancer cells are no longer being destroyed. So cancer that was shrinking or had disappeared may start to grow again and get bigger. This can happen when the genes inside cancer cells mutate. Some gene mutations make cancer cells resistant to chemotherapy and other drug treatments.

If you become resistant to a treatment, your doctor may suggest that you try another one. Many cancers can be cured with treatment. But cancer that is thought to be cured can still come back even years later. This is why some doctors prefer to say that the cancer is in remission. Remission means there are fewer signs and symptoms of a disease such as cancer or that they have completely gone away.

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Launch Interactive Printable Version See how a malignant tumor can progress from a single cell to widespread metastasis. Related Links Angiogenesis Explained See how cancerous tumors recruit their own blood supply in order to grow and how this process might be stopped. This video shows how a type of skin cancer called melanoma can metastasize. Although the appearance of cancer cells and the way they spread varies depending on the type of cancer, the general concepts shown here are useful in understanding how any cancer can spread.

Keep in mind that not all cancers metastasize. Melanoma begins in the melanocytes — cells that produce skin color, or pigment. Melanoma typically begins as a mole. If you catch the melanoma early and it hasn't spread, it can be surgically treated. Here you see a superficial melanoma being removed, along with the surrounding skin.

The extra skin is taken to ensure that no cancer cells are left behind. Melanoma is dangerous because it can spread beyond what you can see, moving deep into your skin where it can gain access to your lymphatic vessels.

This allows cancer cells to travel to distant locations in your body. Cancer cells can also travel to different parts of your body by way of your blood vessels. Cancer cells can break through this membrane. The cancer is called invasive cancer if it breaks through this membrane. As the tumour gets bigger, its centre gets further and further away from the blood vessels in the area where it is growing.

So the centre of the tumour gets less and less oxygen and nutrients. Like healthy cells, cancer cells can't live without oxygen and nutrients. So they send out signals called angiogenic factors. These encourage new blood vessels to grow into the tumour.

This is called angiogenesis. Without a blood supply, a tumour can't grow much bigger than a pin head. Once a cancer can stimulate blood vessel growth, it can grow bigger. It stimulates hundreds of new small blood vessels capillaries :. You can view a transcript of the video. There is a lot of research looking at angiogenesis. We know from research so far that the amount of angiogenic factors is very high at the outer edges of a cancer.

Some cancer drugs can stop cancers from growing their own blood vessels. These drugs are called anti angiogenic drugs. They can't get rid of a cancer but might be able to shrink it or stop it growing. More of these drugs are being developed and tested all the time. We have information about drugs that block blood vessel growth.