In the following work we will talk about breast cancer, its stages and the methods that exist to detect it. We will look at the importance of breast self-examination, which will help us to detect breast cancer. We will also learn about the causes of breast cancer, with avoidable factors such as alcohol and other non-avoidable factors such as ageing. And finally we will see how it can be treated, what different diagnostic tests exist and what treatment options are most effective depending on the type of patient and the stage of the tumour.