carcinomas. There are several less common types which have a generally better prognosis than infiltrating ductal cancer such as medullary carcinoma (6 percent of cases), mucinous (2.5 percent) and tubular (1 percent). Each type has prognostic and therapeutic implications.
How It Spreads After cancer starts, it may be several years before a lump appears. There are wide differences in the way a breast cancer behaves. It may remain confined to the breast for a long time, or, in other cases, spread to nearby lymph nodes and distant organs early in the disease.
What Causes It No definite cause has been established, although genetic factors, personal history and diet all play a role.
