Cell division is a tightly controlled process; a healthy cell responds to signals telling it when to divide and when to stop dividing. Importantly, cells also respond to signals telling them when to die. If these signals are ineffective, a cell can divide and grow uncontrollably and form a tumour. Some of these tumour cells can also break off and spread to form tumours in other organs of the body, a process known as metastasis. Growing tumours can disrupt the function of the organ and lead to the symptoms of cancer and eventually death.
Because cancer can have many different causes and be located in different organs, treatment would ideally be specific to the particular location, type, and stage of cancer, as well as the patient's health and genetics. Some of the most common treatments include surgery, in which the tumour is physically removed, and chemo- and radiotherapy, which preferentially kill rapidly dividing cells. As tumour cells are not the only rapidly dividing cells in the body, such treatments can have undesirable side effects.
In the last few decades immunotherapy has become an important part of treating some types of cancer. Immunotherapy uses certain parts of a person’s immune system to fight diseases. Newer types of immune treatments are now being studied, and they will most likely impact how we treat cancer in the future.