McMaster University

Demystifying Medicine
Seminar Series

Breast Cancer

Breast cancer starts in the cells of the breast. A cancerous (malignant) tumour is a group of cancer cells that can grow into and destroy nearby tissue. It can also spread (metastasize) to other parts of the body. Cells in the breast sometimes change and no longer grow or behave normally. These changes may lead to non-cancerous (benign) breast conditions such as atypical hyperplasia and cysts. They can also lead to non-cancerous tumours such as intraductal papillomas. But in some cases, changes to breast cells can cause breast cancer.

Canadian Cancer Society