What determines the type of breast cancer a patient has?

The type of breast cancer a patient has is determined primarily by which breast cells turn malignant. Breast cancer can originate from different types of cells within the breast tissue, including ductal cells and lobular cells. The characteristics of the malignant cells, such as their origin and specific genetic mutations present, play a crucial role in classifying the cancer type. For instance, ductal carcinoma arises from the ducts that carry milk to the nipple, whereas lobular carcinoma originates from the lobules that produce milk. This classification is essential for determining the most effective treatment options and understanding the behavior of the cancer.

While factors such as the location of the tumor, the patient's age, and family history may provide additional context, they do not directly define the specific type of breast cancer. The distinct biological characteristics of the malignant cells are what ultimately guide diagnosis and treatment strategies.