In some cases, cancer comes back. This mainly happens because tiny cancer cells which are not visible to the naked eye or on scans, can be left out after cancer treatment.
As the time passes, these left cancerous cells begin to divide again and form a tumour eventually. There can be treatment given to get rid of all the cancer so that it doesn’t re-occur. In many cases, an operation is needed to remove the tumour. In order to ensure that all the cancer cells are removed, some healthy cells around the tumour are also removed during the operation.
To reduce the risk of leaving any cancerous cells in the body, other treatments like chemotherapy, radiotherapy and biological therapy may also be given.
However, in some types of cancers operating is not an option. In such cases, chemotherapy, radiotherapy or biological therapy is used. In these treatments, cancer cells as destroyed. A combination of treatments is often given to ensure more effectiveness.
But, no treatment guarantees 100 percent effectiveness. At times cancer cells remain inside the body and cancer can come back, in some cases many years later.
When cancer occurs in the same area of the body, it is known as local recurrence. But if the cancer develops in a different part of the body, it is called metastasis or secondary cancer. If cancer comes back, it can be treated again. Normally, in such a situation, treatment is given to control the cancer but it is possible that treatment is given which aims to get rid of cancer.
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