Congress Abstracts 2003

29

CANCER FAMILY HISTORY: HOW TO DRAW A PEDIGREE. Martha Weinar, RN, MS, Pennsylvania Hospital, Philadelphia, PA; and Lisa Aiello, RN, MSN, Pennsylvania Hematology Oncology Associates, Philadelphia, PA.

The Human Genome Project has allowed us the ability to sequence the entire human genome. Several deleterious genetic mutations have been identified that, when present, dramatically increase one’s risk of developing certain cancers. Through DNA sequencing, scientists are often able to determine whether or not an individual carries such a deleterious mutation. Oncology nurses now have the added responsibility of assessing patients and their families for cancer syndromes to help determine if such a mutation might exist. Oncology nurses need to be educated on the most fundamental steps of performing a risk assessment. It is important to identify individuals who are at increased risk of developing cancer so that they can be counseled on appropriate screening guidelines and/or available risk reduction strategies. Perhaps the most important tool in identifying high-risk individuals and families is the pedigree. Through this visual representation, oncology nurses are able to assess the likelihood of an individual or family carrying a particular mutation.

A pedigree is a visual representation of a family tree depicting the presence and pattern of cancer in a family. The pedigree reveals whom in a family had cancer, the age of onset, the type of cancer, and the relationship of those affected by cancer. This multi-generation drawing provides the clinician with a comprehensive view of cancer in the family and dictates whether or not further evaluation (i.e., genetic testing, high risk counseling) is indicated. Circles represent females and squares represent males. Solid figures represent family members who have been affected and open figures represent either carriers of a mutation or unaffected family members. Lines are drawn to represent relationships such as siblings and offspring.

With the use of this visual tool, oncology nurses will be able to screen patients and determine if further evaluation is recommended. If a pedigree reveals that a pattern of cancer exists in a family, the patient can be referred to a cancer risk evaluation program for in-depth genetic counseling and possibly genetic testing. This will provide patients and family members with appropriate information necessary to make informed decisions about their future health care.