Should I have testing for hereditary cancer?

Should I have testing for hereditary cancer?

This question is becoming a common discussion between patients and healthcare providers, likely due to increasing awareness, increasing availability, and
decreasing cost. Though hereditary cancer syndromes have been around as long as other genetic conditions, it seems that this specific area continues
to garner increasing attention and public interest.

Why has hereditary cancer become such a hot topic in the last few years? There are undoubtedly many reasons that have played into the increased awareness,
but two specific thoughts came to my mind when considering this question.

1) Cancer is common.

Recent estimates from the American Cancer Society show that 1 in 2 men and 1 in 3 women will develop some form of cancer in their lifetime1. With a prevalence
this high, it is easy to imagine that everyone will be affected by cancer at some point in their lives, whether it be a personal cancer diagnosis,
a cancer diagnosis in a family member, or a cancer diagnosis in a friend, coworker, or acquaintance. With such a wide-reaching effect, it makes sense
that people will search for an explanation, even for just a small percentage of the cases.

2) Increased media attention.

One notable instance was in 2013, when Angelina Jolie shared her story with the world. She went public with her decision to undergo a preventative mastectomy
following a genetic test showing that she carries a mutation in the BRCA1 gene, and therefore was at a significantly increased risk of breast cancer
(in addition to ovarian cancer). She later decided to pursue removal of her ovaries and fallopian tubes as well. Her story was soon featured on the
cover of Time magazine, and the increase in the uptake of genetic testing following her announcement was coined “The Angelina Jolie Effect”. A search
of the current medical literature shows at least 13 articles delving into this “Effect” and the impact it has had on the landscape of genetic testing
for hereditary breast and ovarian cancer.

Now, back to the important question. Should you have testing for hereditary cancer?

There are a few things to consider when contemplating the need for genetic counseling and/or genetic testing related to cancer. As already mentioned, cancer
is common. It is important to realize that only 5-10% of most cancer diagnoses are considered strongly hereditary. If we turn that around (as we like
to do as genetic counselors), that means 90-95% of cancer diagnoses would not be considered hereditary, and may have other contributing factors including
environmental exposures, hormonal exposures, or the natural aging process. While the percentage of hereditary cancers may be small, this is a group
of cancers that we can potentially be proactive about. Keep in mind that though breast cancer seems to get the most attention, many other types of
cancer, including colon, ovarian, and thyroid just to name a few, can be hereditary as well.

Here are a few factors that should be considered when determining whether a family has an increased risk of having hereditary cancer syndrome:

• Are individuals in the family being diagnosed at a younger age than typical in the general population? (ie, breast cancer or colon
  cancer younger than the age of 50)
• Are there multiple relatives on the same side of the family with the same type of cancer? Or are there relatives who have been diagnosed
  with multiple primary cancers?  (Common misconception: This does not include metastasis, or cancerous cells spreading
  to other parts of the body.)
• Are there rare types of cancer in the family? (ie, ovarian cancer or male breast cancer)

The question regarding who should have testing for hereditary cancer can sometimes be complex.

If your personal or family history of cancer does raise a concern for you, it is reasonable to have a conversation with your doctor regarding the need
for a genetic evaluation or potentially increased screening. A genetic evaluation is commonly performed by a genetic counselor in the setting of a
Hereditary Cancer Clinic. During this appointment, a detailed family history is taken, and, if it is determined that genetic testing may be warranted,
the benefits, limitations, and result possibilities of available genetic testing will be discussed.

If a hereditary predisposition for cancer is identified in a family, this information can be used to tailor screening and management for those relatives
at a high risk to either detect cancer earlier at a more treatable stage or potentially prevent cancer from developing. Earlier, more treatable cancer
diagnoses and cancer prevention are two very important reasons that I continue to support the efforts of increasing public awareness and knowledge
of hereditary cancers.

Note:

If you think you or your family may be a good candidate for a genetic counseling appointment in regards to hereditary cancer, please talk to your doctor
and visit www.nsgc.org and use the “Find a Genetic Counselor” link to locate a cancer genetic counselor near you.

References:

1. https://www.cancer.org/cancer/cancer-basics/lifetime-probability-of-developing-or-dying-from-cancer.html
2. http://content.time.com/time/magazine/0,9263,7601130527,00.html