Your body is always changing. If you have gray hair or stretch marks, you've probably noticed how your body can change. You may not always notice other ways that your body can change, however. For example, your body's cells constantly change, dividing and creating new cells. You might not notice it when, as your cells divide and copy their DNA (their genetic information), a mutation is introduced.
A mutation is when a cell makes a mistake in copying its DNA for the new cell. Over time, mutations can be introduced to your cells' DNA. These mutations can contribute to the development of cancer. Some of these mutations can be inherited, passed down from generation to generation. Some of these changes can lead to certain types of cancer. These so-called hereditary mutations can also put people who have had cancer at a greater risk for getting another cancer. Hereditary mutations account for about 5 to 15 percent of all cancers.
There are two types of cell mutations, acquired and hereditary.
Acquired mutations occur when a cell's DNA is damaged over time due to environmental influences. These can include cigarette smoke, sun exposure, radiation exposure, and toxins. Cancer treatments, such as radiation and chemotherapy, can also cause acquired mutations. Most cancers have acquired mutations in them.
Hereditary mutations occur when a cell's DNA carries a change that has been passed down from the person's mother or father. This mutation is due to heredity. People with hereditary mutations have that mutation in all of their cells for the rest of their lives. Just as they inherited the mutation from one of their parents, they can pass down this mutation to a son or daughter.
Someone is at risk for having a hereditary mutation if more than two relatives in their immediate family (parents or siblings) have had cancer and:
if these family members had cancer at a young age.
if they had certain types of rare cancers, such as male breast cancer or medullary thyroid cancer.
According to Ellen Matloff, MS, if you've had cancer, you could get it again if you have a hereditary mutation. Matloff is associate research scientist and director of the Cancer Genetic Counseling Program at Yale Cancer Center.
"Even if someone with a hereditary mutation had a cancer, survived the cancer, and had been treated for it, they still have that mutation in many other cells of their body, and can develop a second cancer," she said.
It's important to understand that a second cancer is when a new tumor develops. A second cancer is not a recurrence of the first cancer. An example would be if you had Hodgkin's disease, were treated for it, and then developed breast cancer. Hodgkin's disease does not spread to your breasts; therefore, the second cancer is unrelated to the first cancer. A recurrence is when the cancer was never cured and it redevelops in the same part of the body or it spreads (also called metastases) to another part of the body. An example of a recurrence would be if you had breast cancer and it spread to your bones. The cancer cells now in your bones are breast cancer cells. The bone cancer would be called bone metastases since the breast cancer spread to your bones. You could also refer to this cancer as metastatic breast cancer.
Whether you have cancer or not, it's always important to review your family health history. This lets you see which diseases or conditions, if any, tend to run in your family. Matloff suggested that people get genetic counseling if they think they might have a hereditary mutation. Then, they can decide if they would like to have genetic testing.
Genetic counseling is when an individual or family meets with a professional familiar with genetic testing. This may be your doctor, an advanced practice nurse, a social worker, or someone who is trained as a genetic counselor. During counseling, you will learn about the role of genetics, heredity, and risk. You will also have a chance to ask questions about genetics and genetic testing. In addition, your counselor will prepare a family pedigree and review informed consent with you.