Gabby Cinnamon (Host): Genetics play a significant role in determining traits like hair color, eye color, and height, just to name a few. However, on a more serious note, genetics can also have an impact on our susceptibility to developing certain diseases or conditions. Joining us today to talk about the impact of genetics on cancer risk is Dr. Hamdan.

Intro: Welcome to Conversations on Cancer, brought to you by the Riverside Cancer Institute. Providing answers, debunking myths, and sharing patient stories.

Host: Welcome back to Conversations on Cancer, brought to you by the Riverside Cancer Institute. I'm your host, Gabby Cinnamon. And today, I am joined by Dr. Hamdan, an oncologist and hematologist at Riverside to talk about genetics and cancer risk. Thank you so much for coming back on the podcast today, Dr. Hamdan.

Dr Joehar Hamdan: Good morning. Thanks for having me.

Host: So before we get into the questions, can you just tell us a little bit about yourself?

Dr Joehar Hamdan: Sure. So, I'm a hematologist and oncologist here at Riverside. I've been working at Riverside for eight years. I've been a physician for 16 years. And most of my time has been in cancer medicine and blood disorders.

Host: So, you have a lot of experience. Can you talk about the study of genetics and cancer risk and kind of what all goes into that?

Dr Joehar Hamdan: So, basically, we have to kind of understand the genetics of cancer. And as you alluded to earlier, there are certain reasons why we are tall or short or have blue eyes or dark hair, and similarly, the same with cancer. So, we have genes that are passed down from generation to generation that could increase our risk for cancers. And then if you want to think of conditions such as Down syndrome, for instance, so you may have two healthy parents who raised a child with Down syndrome, and that is because of a mutation that occurred early in the embryo. So, those are the two ways that we may have a genetic predisposition to developing cancer, either it's hereditary or something happened mutation-wise in our early development that increases our risk for cancer.

So basically, when we're thinking about cancer risk, as a physician, we look at, you know, if there are many types or many individuals in the family with the same type of cancer. So if grandma, grandpa, or our aunts or uncles, moms, siblings, all had colon cancer, that should really trigger a red flag that there may be something genetically predisposing them to developing colon cancer. When we think of younger individuals, so if I have a 29-year-old woman with breast cancer, there must be some genetic link, so we must rule that out.

Another condition may be where you have an individual who's had breast cancer and then, down the line, developed colon cancer. That should also raise a red flag. Others include an individual who's had bilateral breast cancer or, if you have a male in the family who's developed breast cancer, it's rather unusual, so that's something that you would consider checking for hereditary cancer syndrome. And then if it's occurring in multiple generations, like I said earlier. So, those are a few of the reasons why a physician may consider testing you or your loved one for hereditary cancer syndrome.

Basically, what it comes down to, the way we are made, we have a system of checks and balances. So, we have genes that are basically there just to ensure that the cells, when they make copies of themselves, that they are doing it correctly, almost like if you want to say when you're typing some type of essay, and the word processor picks up on the misspellings and things of that nature. Similarly, and in a biologic sense, we have DNA that assesses, so it makes proteins that are responsible for double checking the work. And so if those genes that are producing these double checkers, or second checkers, are faulty, that's what's going to increase the risk for cancer. So, that's what would help us understand. There's also conditions like diffuse gastric cancer. So, if you have an individual who's less than age 40 developing gastric cancer, that's something that would make us think, "Hey, is there something going on from a hereditary standpoint?"

Host: Can any type of cancer be inherited or are there certain types that are more linked to genetics? You know, I feel like we hear like you've mentioned breast cancer a few times. I feel like we hear more about that being linked to genetics than we do brain cancer. Would you say that that tends to be more the case or can really any cancer be inherited?

Dr Joehar Hamdan: So, there are the common ones. There are those that are less common. So, breast cancer is more of a common one. Brain cancer actually could be linked to a condition called Lynch syndrome, which is associated with increased risk of developing colon cancer, endometrial cancer, pancreatic cancer, so there are those syndromes.

Head and neck cancer, for instance, is not necessarily associated with a hereditary cancer risk. But we have to realize that if we have a faulty system of checks and balances, and it's struggling replicating accurate cells. And then, you add in environmental factors, well that's going to drive your cancer risk up. So if I have maybe just one faulty gene from one parent, and parent's gene is doing all the work, and then now I have alcohol consumption or I'm smoking heavily, that's going to increase our risk for cancer.

Host: That makes sense because sometimes it's not just the genetics. You could be making choices outside the genetics and it leads to a storm that's compounding and that can cause it.

Dr Joehar Hamdan: Exactly. So just because, there's a tendency for diabetes to run in the family or high cholesterol to run in the family. It's your choice if you're going to make that the reason why you have diabetes or high cholesterol. And if you avoid smoking and you avoid drinking and you exercise, that does decrease your risk for the cancer, even if you have the genetic mutation.

Host: What kinds of genetic testing are out there to find out if you have an inherited cancer gene?

Dr Joehar Hamdan: Well, this day and age is very easy. It's a simple blood test that could be resulted in two weeks time and it will check for the majority of the most common gene mutations and we actually have now even more than those common gene mutations. There is a registry now of mutations we may find in individuals that are considered variants of undetermined significance. But as science continues moving forward, we may be able to say, "Hey, you know what, we have this population with XYZ mutation. Maybe it is a link to this type of cancer or maybe it is a link to having diabetes or things of that nature." So, those are available at our Riverside Cancer Institute.

Host: So, you know, it probably depends on the person, but let's say, you kind of mentioned a family link to breast cancer. You know, your mom got breast cancer and maybe a sister got breast cancer. And so now, you want to do testing to see if you have these genes. Let's say you get this testing and you do have, I believe it's the BRCA gene, what do you do after finding out that knowledge? You know, I'm kind of putting myself in that situation. It's almost like knowing that potentially something terrible is going to happen to you. So, what do you do when you find that out?

Dr Joehar Hamdan: I've run into many occasions where family or patients themselves didn't want to know. They're scared, and then they're concerned about will their health insurance go up in cost. Those are all questions that come to mind. But actually, when we find out that you have a mutation, we're able to address that in an orderly fashion and help prevent that cancer from happening. So in certain young women, let's say they have a BRCA mutation, after consultation with a geneticist, a surgeon, myself, we may talk to the individual about the role of removing breasts at a certain age or removing the ovaries to reduce that risk of that cancer. And the individuals with that diffuse gastric cancer syndrome, we will electively remove the stomach pouch prior to being that age where there's an increased risk of stomach cancer. So, those are scenarios that we would be very helpful in that cancer prevention.

Host: So, kind of in your experience and what you've seen at the Riverside Cancer Institute, do you find that a lot of the cancers that you see can be linked back to genetics? Or is it kind of a mixed bag?

Dr Joehar Hamdan: I think the role of family genetics is important. And I equally, if not more, think it's more common for these sporadic cancers that are more due to environmental exposures. What are you eating? What are these chemicals in your food? Sometimes there are food products that don't expire, you know. So, what is that chemical you're ingesting? You know, you have to be careful about what you do eat. And same as, you know, smoking. And now, this vaping thing that everybody thinks is healthier than smoking, it's actually just as bad, if not worse. Alcohol, you know, there's social drinking and then there's daily alcohol consumption or heavy alcohol consumption on the weekends. That's something we should really try to shy from.

Host: Right. Because as you mentioned before, if you already have a predisposition to developing, then you're only increasing your risk by making other choices.  

Dr Joehar Hamdan: A lot of times I'll get the statements, "Well, nobody in family has cancer, so I'm not concerned." Well, if we go back to the original thing where it could be that point mutation that occurred in your early development, then you don't know if you have that mutation or not. So, why risk it essentially?

Host: Yeah, there are a lot of things out of your control, as we talk about a lot. There are a lot of things out of your control, but there are some things in your control, for sure.

Dr Joehar Hamdan: Definitely.

Host: So before we go is there anything else you would like to add about genetics and cancer risk that you think we should know?

Dr Joehar Hamdan: At times, I run into patients who may not know their family history well. It's not a bad idea to kind of just put something together as a family, some type of log, where Aunt Mary died from what, Uncle David died from what. So that way, the next generation doesn't have to go through that question mark and not know if there is something that runs in the family or not. I run into that quite often.

Host: Yeah. Just thinking when you go to your primary care, they ask, you know, early heart attack, and like those kinds of things. So, cancer is kind of a similar thing too, you know, knowing that really helps you out in the long run, because maybe you need to start getting screened earlier for certain cancers, because you have a genetic predisposition to those.

Dr Joehar Hamdan: And I get that statement, "Oh, you know, so and so died from bone cancer." But actually, it's probably more likely that it was cancer that spread to the bone, which then doesn't help us, so that's why it's important to stick that family ties and know what's going on in the individuals.

Host: Well, thank you so much for coming on the podcast today, Dr. Hamdan. I learned a lot and I feel like everyone listening did too. You did an awesome job explaining everything in a way that's easy to understand, especially for someone-- you know, I don't know a lot about this, so it's great.

Dr Joehar Hamdan: It's my pleasure to participate.

Host: And thank you listeners for tuning in to Conversations on Cancer brought to you by the Riverside Cancer Institute. For more information about cancer care at Riverside, visit riversidehealthcare.org/cancer. Also, make sure to rate and leave a review for our show on Apple, Spotify, or wherever you listen.