A family history of cancer can raise concerns about one’s health. Having relatives who have had cancer does not automatically mean an individual will develop it. This article explains what a family history of cancer means for you and outlines proactive steps.
Defining Significant Family History
A general family history differs from a medically significant one, which warrants discussion with a healthcare provider. A significant family history often involves specific patterns or types of cancer. For example, a diagnosis in one or more first-degree relatives (parent, sibling, or child) is more significant than in distant relatives. The risk for breast cancer, for example, doubles if a mother, sister, or daughter had the disease.
The age at which cancer was diagnosed in relatives also plays a role; diagnoses at an unusually young age (often under 50 for common cancers like breast or colorectal cancer) indicate risk. Patterns where multiple relatives on the same side of the family have the same type of cancer, or related cancers like breast and ovarian, or colon and uterine, also indicate heightened risk. The presence of rare cancers or multiple distinct cancer types in a single individual also indicates a significant family history.
Cancers can broadly be categorized into three types: sporadic, familial, and hereditary. Sporadic cancers (75-80%) occur by chance due to aging, environment, and lifestyle, with no inherited gene involved. Familial cancers cluster within a family, occurring more often than expected, often at a younger age, but without a clear pattern of inherited gene mutations. This type arises from a combination of minor genetic factors and shared environmental or lifestyle influences.
Hereditary cancers (5-10% of all cases) are caused by a specific inherited gene mutation passed down through generations. Individuals inherit a predisposition, not the cancer itself.
Collecting Your Family’s Health Information
Gathering detailed health information from your family members provides valuable insights for assessing your cancer risk. Begin by identifying all blood relatives on both your maternal and paternal sides, including parents, grandparents, aunts, uncles, siblings, nieces, nephews, and children. Include information about deceased relatives, noting their age at death and cause, if known.
For each relative with cancer, record the exact type of primary cancer diagnosed (including subtypes) and the approximate age at diagnosis. Note if any relative had more than one distinct cancer diagnosis or underwent genetic testing. Approaching these conversations with sensitivity is helpful, as some family members may be hesitant to share personal health details. Resources like the CDC’s “My Family Health Portrait” app or other online tools can assist in organizing this information.
The Role of Genetic Counseling and Testing
For individuals with a significant family history of cancer, genetic counseling is often the next step. This involves meeting with a trained professional, a genetic counselor, who reviews your personal and family medical history to assess your inherited cancer risk. Even without genetic testing, a genetic counselor can provide a comprehensive risk assessment and discuss appropriate screening or prevention strategies.
Genetic testing involves a blood or saliva sample, analyzed for specific inherited gene mutations linked to an increased cancer risk. For instance, mutations in BRCA1 and BRCA2 genes are associated with higher risks for breast and ovarian cancers. Mutations in mismatch repair genes (MLH1, MSH2, MSH6, PMS2, EPCAM) are linked to Lynch syndrome, increasing risks for colorectal, uterine, and ovarian cancers. If a specific mutation is identified in a family member with cancer, other relatives can then be tested for that particular mutation.
A positive genetic test result means a specific inherited gene mutation was found, indicating an increased risk for certain cancers; however, it does not guarantee that cancer will develop. Conversely, a negative result means the tested mutation was not found, but it does not eliminate all cancer risk, especially if a strong family history still exists. In some cases, tests may yield a “variant of uncertain significance” (VUS), meaning a change was found but its link to cancer risk is not yet clear. Genetic counseling helps interpret these complex results and guides decisions about future health management.
Managing Cancer Risk Proactively
Understanding your cancer risk through family history and genetic insights allows for proactive health management. Personalized screening protocols are recommended for individuals at higher risk. This can involve starting screenings at a younger age, undergoing more frequent tests, or utilizing different screening methods than those recommended for the general population. For example, women with a strong family history of breast cancer might begin mammograms earlier, potentially with additional imaging like breast MRI.
Beyond screening, certain risk-reduction strategies can be discussed with a healthcare provider for individuals with very high inherited risk. These options can include specific medications or preventative surgeries to remove high-risk tissues. For instance, some women with BRCA mutations might consider risk-reducing mastectomy or removal of ovaries and fallopian tubes. These decisions are highly individualized and require thorough discussion with medical professionals.
Regardless of family history or genetic predisposition, adopting a healthy lifestyle remains an effective strategy for cancer prevention. Maintaining a balanced diet rich in fruits, vegetables, and whole grains, engaging in regular physical activity, achieving and maintaining a healthy body weight, avoiding tobacco products, and limiting alcohol consumption can significantly lower overall cancer risk for everyone. These lifestyle choices contribute to general well-being and can help mitigate various health risks.