The mammography does not prevent cancer but can save lives by the timely discovery of the cancer.
In the past, the breast cancer was diagnosed in advanced stage when the tumor was already palpable. Nowadays, due to the imaging investigation methods, the cancer can be diagnosed in early stage when its dimensions are much smaller and it is not spread to the lymph nodes, the current studies showing that the mammography can reveal breast lesions two years before they can be clinically detected. Furthermore, the early diagnostic, when the tumor has small dimensions, removes the need of the mastectomy (breast removal), the excision of the tumor being enough in order to mitigate cancer risks.
The ignorance, fear of diagnostic and the lack of health education are the factors due to which the disease is diagnosed in an advanced state.