Kristie L. Kahl: What are family risks associated with colorectal cancer, including Lynch syndrome?
Zsofia Stadler: For colon cancer, we know that in the United States, every individual has about a 5% lifetime risk of developing colon cancer. If you have a family history of one first-degree family relative, so that would be a parent or sibling with colon cancer, that risk increases two-fold, or a 10% lifetime risk of colon cancer. Certainly, family history is an important risk factor. In Lynch syndrome, which is the most common hereditary colon cancer predisposition syndrome, the lifetime risk for colon cancer is up to 70%.
So, it’s a very high risk of colon cancer. In addition to colorectal cancer, these patients are also at risk for a variety of other cancers, including women for endometrial cancer, ovarian cancer; men and women for gastric cancer, urothelial cancer, pancreas cancer. It’s really a pan-cancer syndrome.
Kristie L. Kahl: Why do you think we don’t talk about Lynch syndrome as much?
Zsofia Stadler: We are certainly trying to get the word out there. There are many organizations, like the Colon Cancer Foundation, that are trying to get the word out about Lynch syndrome. Interestingly, Lynch syndrome is quite common.
It’s estimated that approximately 1 in 300 individuals have a Lynch syndrome, but it’s not as well tested for as BRCA1 and BRCA2, probably because we have known about BRCA1 and BRCA2 genes for a little bit longer and we have just started to appreciate how common Lynch syndrome really is in the population. So, I think it’s time to get the word out there about colon cancer risk and Lynch syndrome.
Kristie L. Kahl: How can we help to raise more awareness around this?
Zsofia Stadler: There are many different organizations that are raising more awareness. AliveNKicking is one of them. We’ve worked a lot with the Romeo Milio Lynch Syndrome Foundation as well, the Colon Cancer Foundation. I think that it is extremely important.
It’s also important for medical geneticists to get the word to primary care physicians. By the time the patients present to the colorectal surgeon or the medical oncologists, or even to the gastroenterologist, during their colon cancer diagnosis, it’s too late. And usually in the setting of Lynch syndrome, there is some family history of colorectal cancer or endometrial cancer. So, if we could engage the primary care physicians to recognize Lynch syndrome as a warning sign that maybe these patients need to be referred to for genetic testing, that would be wonderful.
Kristie L. Kahl: What role does the genetic counselor play with all of this?
Zsofia Stadler: Genetic counselors are specifically trained to talk to patients about genetic testing for genetic predisposition syndromes, and they provide counseling in the pre-genetic test appointment. Then they provide the genetic testing and give recommendations after genetic testing, including what kind of surveillance or risk-reducing surgeries a patient should undergo.
Moreover, they also help to identify at risk family members who also need genetic testing. So, they are able to provide the counseling and interpret the test results and engage other family members as well.
Kristie L. Kahl: Who should go to a genetic counselor?
Zsofia Stadler: Right now, we recommend that all patients who have a diagnosis of colorectal cancer have at least their tumor tested for markers of Lynch syndrome. This can be done with two different tests — an immunohistochemical stain or a microsatellite instability tumor testing. If either one of those is positive or abnormal, then those patients automatically need genetic testing.
In addition, patients who have very early onset colon cancer should be evaluated, or those with a personal or family history of polyps that lead to very high risk of colorectal cancer.
Kristie L. Kahl: How can we help families to have these conversations?
Zsofia Stadler: It’s very interesting because in the medical genetics field, especially in older generations, talking about cancer is a little bit taboo. No one wants to talk about it. Oftentimes, patients and families don’t know what types of cancer grandma had, and that’s especially true with the gynecologic malignancies.
They would say, “she had a female cancer,” but that could be ovarian, uterine or cervix, and whichever it is, that implicates different potential etiologies. It’s very important that families talk about not just the fact that someone had cancer in the family, but what kind of cancer they had. At what age were they diagnosed? Because colon cancer at age 85 or 40 are very different in terms of genetic risks.
Kristie L. Kahl: If we start these conversations earlier, how can that reflect on diagnosing earlier?
Zsofia Stadler: If everyone realizes that even having one first-degree relative with colon cancer at age 60 or under, all of those individuals need colonoscopies starting at age 40. So, sometimes what happens is the primary care physicians don’t even start to talk about colon cancer risk until age 50, at which time they usually start colonoscopy screening. But in some individuals, if the primary care physician was aware of the family history then they may have initiated colonoscopies sooner, or if they were aware of the polyp history.
Kristie L. Kahl: How can we help to educate primary care physicians?
Zsofia Stadler: One of the most important parts that a primary care physician can play is to take an accurate family history questionnaire. This is a relatively accurate and easy tool to implement and there have been efforts to use a tool that goes into the EMR and estimates the risk, which would be wonderful. The data shows that primary care physicians are pretty good at asking about parents. Where the primary care physicians get a little bit less exact is second-degree family history, including grandparents, aunts, uncles and even siblings, they don’t ask about that.
Also, family histories are dynamic. So, if you take a family history to the initial appointment with your primary care physician, it needs to be updated over time. So, patients need to know if there is a new diagnosis in the family, they have to inform their primary care physicians. But at the same time, the primary care physicians should be asking the patient once in a while, “Is there anything new going on in your family? Has anyone been diagnosed with cancer?” Because sometimes, these family histories change, and you could uncover a genetic predisposition syndrome.
Kristie L. Kahl: What is your biggest piece of advice for someone who thinks they’re at risk for colorectal cancer?
Zsofia Stadler: Talking first to your primary care physician, see if you need to see a genetic counselor for genetic testing. I think that’s the first step. If you don’t have a primary care physician, you can also reach out to a genetic counselor and see if you meet guidelines or criteria for genetic testing.
Transcription edited for clarity.