Genetics and management of inherited cancer predisposition 1

Published on February 29, 2016   25 min

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Other Talks in the Series: Cancer Genetics

JOSHUA SHIFFMAN: Hello. My name is Joshua Shiffman. I am a pediatric oncologist at the University of Utah, where I take care of patients with hereditary cancer syndromes as well as do research in the field.
Today, we're going to talk about the importance of family history. We will cover several of the more common hereditary cancer syndromes including, GI cancers, breast cancers, Li-Fraumeni Syndrome, Paraganglioma and VHL syndromes. And finally, we'll end with some brief discussion about research in the field of hereditary cancers specifically related to comparative oncology.
Cancer is quite common. In fact, it is one of the leading causes of death around the world, and 15 people will die from cancer every minute. Half of all men and a third of all women will develop cancer throughout their lifetime. This makes the study of cancer and the risk for cancer quite relative to disease and impact on human health.
In terms of the genetic risk for cancer, we believe that as many as 1 in 10 adults will have cancer that is caused to an inherited genetic risk. This comes to approximately 160,000 new diagnoses per year for cancer in the US alone. In terms of childhood cancer, we believe that it may be as high as 1 in 3 children who have developed cancer due to an inherited genetic risk. This comes to approximately 4,500 new diagnoses for cancer per year.
All told, when you add everything together and you take into account the carrier rates for some of the more common hereditary cancer syndromes, the genetic risk for cancer may be as high as 1.7 million people living in the US alone who are at higher risk for developing cancer. New research out of St. Jude's Children's Hospital, where they looked at childhood cancer and used a control cohort which included the 1000 Genome Project, estimated that nearly 1% of people who are in the healthy control population may actually be harboring high print penetrance genetic risk for cancer. This would put the rate of people living with cancer, at least in the US, as high as .3 million for those at risk due to underlying genetics. This is an incredibly high number. And what we'll talk about today is how can we identify those individuals? And most importantly, how can we make an impact on their lives and hopefully improve their outcome by detecting cancer at a really very early stage of development?
When we think about hereditary cancer syndromes, as you can see in this illustration, it is as if these patients have a sword hanging over their head, a sword that is suspended only by a teeny, teeny hair from a horse's tail. This is known in common terms as Damocles' Sword. When you talk and care for these patients with hereditary cancer syndrome, they tell you it's as if they're living with this sword hanging above their head, and they never know when it's going to drop. Our job as clinicians, health care providers, scientists, researchers, is to understand more about the risk for cancer development. And again, what can we do to possibly intervene?
The first step in identifying patients at risk for genetic syndrome is to take a very good cancer family history. To do this, you need to obtain at least three generations on the pedigree, and you need to ask about every person in the family, including what was the age of the initial cancer diagnosis. How did the patient die? Was it a primary diagnosis of cancer or was the cancer that they're describing from a metastasis? Were their precursor lesions? Were there multiple cancers? Were there bilateral cancers? So the same cancer on either side. For instance, Wilm's tumor. Was it on one kidney or both kidneys? Did they have any prophylactic surgeries? Sometimes women will tell you, look, there's no history of cancer in my family. But when you dig deeper, you realize that every woman in the family for the past three generations has had bilateral mastectomies. That's a clue, and that should let you start thinking about the risk for breast cancer in the family. There are also congenital abnormalities that are associated with cancer. And lastly, it's important to record ethnicity and race as some ethnicities and races are more predisposed for harboring genetic risk for cancer.

Genetics and management of inherited cancer predisposition 1

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