Genetics and Cancer: Straightforward answers to important questions

These are genetic alterations that increase the risk for developing a certain type (or types) of cancer. They are usually transmitted from parent to child. Someone with an inherited cancer susceptibility factor is at increased risk for eventually developing cancer; however, not everyone with a susceptibility factor develops cancer.

Even though most cancers are not related to hereditary genetic factors, in certain cases the genes we inherit from our parents play a role in cancer development. The BRCA1 and BRCA2 genes are the most common inherited susceptibility factors for breast and ovarian cancer.  There are several other genes that account for increased risks for colon and uterine cancer, pancreatic cancer and melanoma, colon cancer associated with multiple polyps, and several other genetic conditions in which multiple malignancies are present.

Anyone with a personal and/or family history of cancer.  While many individuals have one or more close relatives who have been diagnosed with cancer, genetic susceptibility factors are usually associated with cancers that are discovered at relatively young ages, individuals with two or more cancers, or a history of having several relatives with the same type (or types) of cancer. Primary care physicians are often able to determine whether a genetic consultation, for a formal risk assessment and consideration of genetic testing, is warranted.

The geneticist obtains a detailed medical history, including information about a suspected or proven cancer diagnosis. A complete family tree is constructed, and pertinent medical records are reviewed. The consultation is conducted by a genetic counselor and physician-geneticist and takes approximately one hour.  Three important questions are addressed during a genetic evaluation. First, is a hereditary factor a possible explanation for the cancer diagnoses in the family? Second, what is the likelihood that a factor will be identified?  Finally (and sometimes most importantly), who is the ideal person in the family for testing or further evaluation?

The actual sample collection process is very straightforward; after appropriate written informed consent is obtained, a small blood or saliva sample is obtained and sent to the genetic testing  laboratory. The laboratory performs highly sophisticated genetic analysis on the DNA extracted from the blood specimen. Depending on the specific testing requested, results can be available in as little as one to two weeks. A follow up visit is arranged to discuss the result and clinical implications for both the individual who was tested and their family members.

Test results, both positive and negative, provide valuable information for optimal cancer treatment, surveillance, and prevention.

In general, the answer is yes.  Genetic consultation is covered the same way as for any medical specialist.  Since genetic testing can be quite expensive, many managed care plans have criteria for when testing is reimbursable.  It is highly unusual for genetic testing that we as geneticists order to be rejected for coverage by a medical insurer.  Both federal and New York State regulations provide protection against discrimination by employers and health insurance companies based on results of genetic testing.

To some extent, yes. However, genetics is a rapidly changing and highly specialized field.  Genetics professionals are trained in genetic theory and practice and are keep current with the latest technological advances that might benefit their patients. Geneticists have statistical data, probability models, and valuable insights that aid patients and physicians in considering the pros and cons of genetic testing.  A geneticist's expertise is particularly helpful in ordering the appropriate test(s), as well as interpreting and explaining genetic test results to patients and physicians.
 

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