How Do I Prepare a Family Cancer History for Genetics?

When you schedule an appointment with a genetic counselor to discuss your risk for Hereditary Breast and Ovarian Cancer (HBOC) syndrome, their first tool will be your family tree. To accurately assess your genetic risk, you need to provide a three-generation family health history including cancer types, ages at diagnosis, and ages of death for relatives on both sides of your family ^[1][2][3].

Please know this upfront: It is incredibly common for families to have lost touch or kept health details secret. Do not panic if your family tree has gaps. Gathering this information is not a test you can fail. Just collect whatever you comfortably can—even a partial history is immensely helpful ^[4][5].

Mapping Three Generations

A complete family history, often called a pedigree, looks at patterns of disease across three generations ^[1][2]. It is a common misconception that breast or ovarian cancer risk only passes down through the mother’s side. In reality, you can inherit a cancer-risk gene from either your mother or your father, making both lineages equally critical for your risk assessment ^[6][7].

When gathering names and information, try to include the following first-, second-, and third-degree relatives ^[7]:

• First-degree: Your parents, siblings, and children.
• Second-degree: Your grandparents, aunts, uncles, nieces, nephews, and half-siblings.
• Third-degree: Your first cousins and great-grandparents.

The Details to Collect

For every relative who has had cancer, try to gather the following details. If you don’t know the exact answers, that is okay—just bring what you know.

• Primary cancer site: Try to find out exactly where the cancer started ^[5]. For instance, clarify vague terms like “female cancer” or “womb cancer.” Distinguishing between cervical cancer, uterine cancer, and ovarian cancer is very important because ovarian cancer is a hallmark of HBOC ^[8][5]. If you only know a relative had “stomach cancer,” simply report that. If a relative already has copies of their pathology reports on hand, those are fantastic “bonuses” to share with your counselor, but you do not need to go on a scavenger hunt for them ^[4][9].
• Age at diagnosis: Note how old your relative was when they were first told they had cancer ^[3].
• Current age or age at death: Record their current age if they are living, or the exact age and cause of death if they have passed away ^[5]. If a family member happens to have a death certificate, it can act as a helpful bonus for verifying information ^[9].
• Prior genetic testing: Ask if anyone in your family has ever had genetic testing for cancer risk ^[9]. If they have, try to find out when they were tested and see if they can share a copy of their lab report. Older tests may have only checked for BRCA1 and BRCA2, missing other important genes that we know about today ^[10][11].

Important Clues for HBOC

While preparing your history, pay special attention to certain red flags that are strongly linked to HBOC and mutations in genes like BRCA1 and BRCA2 ^[12]. Make sure to highlight if your family history includes:

• Specific cancer types: Aside from breast cancer, HBOC is linked to elevated risks for ovarian cancer, pancreatic cancer, aggressive prostate cancer, and melanoma ^[13][12]. An ovarian cancer diagnosis at any age is considered a significant red flag ^[14][5].
• Young or rare breast cancers: Note any cases of breast cancer diagnosed before age 50, male breast cancer, or triple-negative breast cancer (a specific subtype often linked to BRCA1 mutations) ^[15][14].
• Multiple primary cancers: Mark down if a single relative was diagnosed with two completely different, new cancers (like breast cancer in both breasts, or both breast and ovarian cancer) ^[3].
• Ashkenazi Jewish ancestry: Individuals with Eastern European (Ashkenazi) Jewish ancestry have a significantly higher chance of carrying certain BRCA mutations, so be sure to mention this heritage if it applies to either side of your family ^[14].

Having the Conversation

Talking about cancer and passing away can be difficult for many families. Approach the conversation gently, perhaps explaining that you are putting together a family health tree for your own preventative care. Writing things down in a notebook or using a family history questionnaire can help you stay organized and make the process feel more manageable ^[16]. Ultimately, your genetic counselor will use whatever information you can provide to tailor the best possible care plan for you ^[4][9].