There are several reasons why drinking alcohol causes cancer. It is likely that different cancers are caused in different ways, for example:

• Ethanol and acetaldehyde: alcohol (ethanol) is converted in our bodies into a chemical called acetaldehyde. Both ethanol and acetaldehyde are cancer-causing substances.
• Liver cirrhosis: alcohol damages the cells of the liver and can cause a disease called liver cirrhosis. Cirrhosis makes you more likely to develop liver cancer.
• Hormones: alcohol can increase the levels of some hormones, such as estrogen. High levels of estrogen increase the risk of breast cancer.