How Breast Cancer Develops

Genetically abnormal cells in the body cause all cancer types, including breast cancer.  A tumor develops when the abnormal cell divides and multiplies into a mass of cells. These cells may eventually spread through the body via the blood system.  The cancerous cells may infect nearby lymph nodes, which are small, bean-shaped organs spread through out the immune system.  The lymph nodes located under the arm are susceptible to tumor cells spreading from breast cancer.  The spreading of cancer cells to other parts of the body is called metastasis.  Most breast cancer metastasis affects the bones, lungs, and liver.  However, it is possible for cancer to spread to any site in the body.

Early detection is critical for breast cancer treatment.  Regular breast examinations and mammography can help detect a cancerous tumor before it spreads to other parts of the body.  Treatment is most effective when breast cancer is detected early.

Breast cancer is highly erratic and difficult to predict.  Almost all breast cancers are sporadic, meaning there is no genetic cause.  Genetic mutations cause only 5-10% of breast cancers.  People with more than one relative diagnosed with breast cancer have a higher change of inheriting the disease.  The most common cancerous genetic mutations are BRCA1 and BRCA2.  Women can help determine if genetic testing is appropriate for her or her family members by consulting a genetic counselor that is trained to determine genetic cancer risk.