HEREDITARY, FAMILIAL, SPORADIC…WHAT DO THEY MEAN?

Most cancer occurs as the result of a combination of inherited and environmental factors.  Some cancers are strongly influenced by environmental factors, while others have a stronger inherited component. 

 Sporadic Breast Cancer

The great majority of  families (about 80%), have only a few women with breast cancer, most of whom have been diagnosed post-menopausally (after age 50).  In these families, the inherited component to breast cancer is likely to be small and the family members do not have a strong inherited risk to develop breast cancer.   The risk in these families is more likely to be influenced by medical and lifestyle factors. 

Familial Breast Cancer

In about 15% to  20% of families, breast cancer occurs in more than one person on the same side of the family.  There are several explanations for such “clusters” of breast cancer in families, one of which is that there may be genes that  have only a weak influence the development of breast cancer.  Research into this possibility is on-going.  Another explanation is that the family members had a similar environmental exposure.  It is also possible that, more than one family member has breast cancer just by chance alone, since breast cancer is a relatively common disease

Hereditary Breast Cancer

In a few families (about 5% to 10%), breast cancer is clearly being inherited from generation to generation.  In these families, breast cancer is typically diagnosed at an early age (younger thab 50 years).  It is not unusual to see women with breast cancer that occurs in both breasts, or sometimes, family histories that include both breast and ovarian cancer.  These families have an increased chance to have an inherited gene mutation for which we can offer testing.