What is Hereditary Breast & Ovarian Cancer Syndrome (HBOC)?

Most people are familiar with cancer. Its prevalence in the world has grown over the years to the point where almost everyone knows someone directly affected. However, not everyone is aware that there are certain genetic conditions that can increase your chance of cancer dramatically. Below are some common questions about one of these conditions, HBOC, and its underlying genetic mutations.

What is HBOC?

Affecting less than 1% of the entire population, Hereditary Breast and Ovarian Cancer Syndrome (HBOC) is a medical condition caused by an inherited genetic mutation which raises an individual's risk for cancer. Commonly, it is caused by a mutation in either the BRCA 1 or the BRCA 2 genes, though there are some other minor mutations which could lead to HBOC. While it is most notably linked to breast and ovarian cancer, HBOC also raises the risk of melanoma, stomach, esophageal, fallopian tube, pancreatic, and prostate cancer. Additionally, it affects both men and women, though a woman's risk is sometimes higher than a man's.

How is it developed?

HBOC is an inherited genetic condition that can only be obtained by a parent passing down a mutated gene. Ordinarily, each person has two copies of each gene: one inherited from their mother and one inherited from their father. HBOC follows what is called an autosomal dominance pattern, which means only one gene needs to be affected in order for the child to have an increased risk. Therefore, if a parent caries a mutated BRCA gene (either 1 or 2), then the child has a 50/50 chance of inheriting that gene and developing HBOC.

How is HBOC diagnosed?

HBOC is diagnosed once a BRCA gene mutation has be found. Most commonly, this is done through genetic testing by either a blood or saliva sample. Reputable test centers then use these samples to look for either mutations, duplications, or deletions, all of which could increase your risk for cancer.

It is important to note that genetic testing is a highly specific science and life altering tests, such as for BRCA mutations, should not be left to those do-it-at-home kits. While they may say they test for BRCA mutations, these kits currently can only test for 3 out of thousands of mutation types and could miss a positive diagnosis. For example, my father used one of those kits and it old him he was negative for a BRCA 1 mutation. We later found out that was wrong.

What are the risks?

Because HBOC is developed due to a genetic mutation, the chances of having it are low (about 1 in 600). However, once a person has it the risks associated with HBOC are quite high. HBOC is caused by a mutation in either a the BRCA1 or the BRCA 2 gene. As part of a group called the "tumor suppressor" genes, these sections of DNA work to regulate cell growth and prevent tumors. Therefore, when these genes are damaged by a mutation, it can result in uncontrolled cell growth and the development of cancer. People with a BRCA mutation may have various risk levels, but on average women with HBOC have a 75% chance of developing breast cancer and a 30% chance of ovarian cancer. Compare this to the average woman whose chances are 7% and 0.7% respectfully. (My risk scores are 87% and 63%.)

When it comes to the actual type of cancer, women with a BRCA 1 mutation are at an increased risk for developing triple negative breast cancer. This type of cancer does not have receptors for estrogen, progesterone, or HER2, making it very difficult to treat. Women with a BRCA 2 mutation are at risk for developing HER2 negative breast cancer.

Can you lower your risk?

Because HBOC is inherited through your genes, there is no way to prevent the condition. However, if a parent knows they are positive for a BRCA gene mutation, they may choose to undergo preimplantation genetic diagnosis. This method involves testing fertilized eggs for the mutation and then implanting the ones most desirable through in-vitro fertilization. The process however is expensive and may raise some physical and emotional strains.

On the other hand, once a person knows they have HBOC there are a few procedures and practices they could undergo in order to minimize their cancer risk. The first involves various drugs and continued screening. Women with HBOC may be able to take certain chemoprevention drugs and hormone replacements (like oral contraceptives) to help reduce the risk of developing cancer. However, it is important to note that certain hormone receptor-negative cancers may not be affected by this approach. Additionally, the taking of oral contraception may lower a women's risk of ovarian cancer but could actually increase her risk of breast cancer.

Women who choose to take preventative drugs instead of surgery, or those who just want to "wait and see," will then need to undergo continuous screening. This includes mammograms, MRIs, breast and pelvic ultrasounds, and bloodwork done on a rotating basis throughout the year. These screenings are typically started at the age of 25 and continue for life or until the individual chooses to have risk reducing surgery.

The other option is to elect to have prophylactic surgery. A double mastectomy (removing the breast tissue) could reduce a women's risk of developing breast cancer by 90%. Additionally, a salpingo-oophorectomy (removal of the ovaries and fallopian tubes) can reduce the risk of fallopian and ovarian tube cancer by just as much. However, with these major surgeries comes major life decisions and changes. A person considering surgery may need to consider implants, family planning, and the onset of early menopause.