It is thought that most of the variation between areas is due to the characteristics and behaviours of the people living within each area. This may relate to known risk factors for cancer, such as smoking, excessive alcohol consumption, poor diet, inadequate physical activity and sun protection. It may also relate to the use of cancer diagnostic procedures, such as having access to skin checks for melanoma, or mammograms for breast cancer. However, there is also much that is not known, and uncovering reasons for the geographical variation in cancer diagnoses will be an ongoing priority for researchers.