Cancer is the term for a group of over 100 different diseases. Cancer is characterised by the uncontrolled growth of abnormal cells occurring in multiple phases.
There are more than two hundred (200) different kinds of cancer. Cancer can develop in almost any organ or tissue, such as the lung, colon, breast, skin, bones, or nerve tissue. (PubMed Health)
Not all cancers kill.
Overall, more than 50% of people diagnosed with cancer live for more than 5 years. Some cancers have survival rates of more than 90%. Early stage cancer also does not kill. It is for this reason that early diagnosis is so important – it is during early stage cancer that treatment is likely to work best. Cancers can cause death in more than one way. There is, therefore, no single answer to the question of how cancer kills. It really depends on the type of cancer one has and which parts of the body are affected. (Cancer Research UK)