2 January 2015 Last updated at 14:09 GMT
New research has suggested that most types of cancer are the result of bad luck, rather than an unhealthy lifestyle or genetic factors.
The study, by scientists in the US, found two-thirds of cancers such as liver, pancreatic and thyroid, were caused by random mutations as cells divided.
The team said the best way to tackle such cancers was through early detection.
Adam Brimelow reports.
