Few, if any, families have not been affected by cancer. While no individual or family is immune to cancer, some families may be more at risk of developing certain types of cancer than others.
In many instances, cancers that run in families can be linked to behaviors that families share. For example, families that smoke tobacco may be more vulnerable to cancer than those that don’t, as the smoke from tobacco is known to contain dozens of carcinogens. Cancer can affect multiple generations even in families in which only one person smokes, as exposure to secondhand smoke also increases cancer risk.
But poor behaviors or the effects of those behaviors are not the only cancer risk factors that can be passed down from generation to generation. According to the American Cancer Society, between 5 and 10 percent of all cancers result directly from gene mutations inherited from a parent. When cancers within a family are strongly linked to such mutations, this is known as family cancer syndrome.
Cancer is not necessarily caused by a family cancer syndrome, even if gene mutations are inherited. But the following factors may make it more likely that cancers in a family are caused by a family cancer syndrome:
• Many cases of the same type of cancer, especially if the cancer is considered uncommon or rare
• Cancers that occur at an abnormally young age within a family compared to the median age such cancers are typically diagnosed among the general population
• More than one type of cancer in a single person
• Cancers that occur in both of a pair of organs, such as in both kidneys, both breasts or both eyes
• More than one childhood cancer in siblings
• Cancer that occurs in a sex that is not usually affected by that type of cancer, such as a man being diagnosed with breast cancer
Before discussing the potential of a family cancer syndrome with their physicians, men and women can survey their family histories with the disease. Adults can make a list of the people in their families who have been diagnosed with cancer, noting their relationship to each individual and which side of the family each person is on. List the type of cancers each person was diagnosed with, placing an asterisk or note next to types that are considered rare or unusual. In addition, list the age of diagnosis for each family member and whether or not they developed more than one type of cancer. While this may be difficult to determine, try to learn if each relative diagnosed with cancer made any lifestyle choices that might have contributed to their diagnosis. Such choices include smoking, alcohol consumption, diet, and activity level.
Family cancer syndromes are rare, but understanding them can still help families make the right lifestyle choices. More information about family cancer syndromes is available at www.cancer.org.