Hung Doan, M.D., Ph.D. Hi, I'm Hung Doan, an associate professor of Dermatology at MD Anderson Cancer Center. I'm joined today by my colleague, Dr. Pamela Schlembach, a professor of Radiation Oncology at MD Anderson Cancer Center, and this is the Cancerwise Podcast. Hi, Dr. Schlembach, thanks for joining me today.  

Pamela Schlembach, M.D. Thank you, my pleasure.  

Hung Doan, M.D., Ph.D. Today we're here to talk about how cancer patients and survivors can stay healthy during the summertime, as they consider travel, as they consider being more outdoors, and also issues of hydration. What advice can you give cancer patients and survivors about these issues?  

Pamela Schlembach, M.D. So, one of the things that I like to talk to patients about is dehydration. Hydrating is very important even when you're healthy, but when you have cancer, a lot of times you're not as hydrated as you should be and it's for good reason. Sometimes things don't taste well, sometimes you're fatigued, you don't feel like eating. You could have nausea so you're not drinking as much as you could, or you could even have diarrhea, and these are all based on the facts that patients are having cancer treatments, and they affect them in different ways. So, these are some of the concerns that I have when I talk with my patients. So, one of the first questions I ask them are, 'Tell me about what you're drinking.' And they are usually quick to say, 'Well, I'm drinking coffee, tea, soda, maybe alcohol.' And then I explain to them, 'Well, do you realize that that might be dehydrating?' And a lot of times they don't. And so, I'll share with them about the importance of water. And I say, especially in the summer, you're gonna have not only your normal needs, but then you've got all the heat that we have in Texas, and you might be outside more than you normally are. So, I share with him about the importance of drinking water. So, then I go into, how about tell me your water intake? And they usually say, which is surprising, 'I don't like water.'  

Hung Doan, M.D., Ph.D. Right. I mean, we have to worry about what we call the insensible losses too, as we sweat, work outdoors, like you say, or even the compromised skin barrier. Certainly, when patients are undergoing treatments that may impact the skin, including chemotherapies that can impact the palms and the soles, make swelling of the skin, but also radiation therapy where your expertise comes in, too.  

Pamela Schlembach, M.D. Yeah, absolutely. And so, some of the ways that I talk to the patients about that because, you know, they are going to have more needs is, 'Let's talk about how we can make water taste a little bit better.' So, I'll say you can add vegetables to water.  

Hung Doan, M.D., Ph.D. Oh, that's a great idea. Either cucumber, fruits, a little bit of that. You also get some electrolytes in there.  

Pamela Schlembach, M.D. Absolutely, and we do talk about fruit and then if they don't want to do that I'll say, 'Do you like juice?' And most people like juice, and I say, 'How about if you take a quarter cup of juice and add it to a pitcher of water?'  

Hung Doan, M.D., Ph.D. Oh great idea.  

Pamela Schlembach, M.D. And that's a good way to get hydration. So, that's one of the key components, that I find and a lot of people don't drink enough water as it is, cancer and non-cancer patients, and then the symptoms from that can just be something like a headache and fatigue. So, that's one of the first questions I ask them when they share those kind of symptoms with me. And it's so important during the summer months.  

Hung Doan, M.D., Ph.D. I think raising that issue, especially in this podcast, allows for patients to really reflect on that, even if they may not explicitly discuss it with their provider, too. So, thanks for bringing that up. I think hydration is very important. From our skin standpoint, I sometimes, should patients come up or ask about that, if the issue arises, I do recommend either a moisturizer that contains ceramides. That's a great product because it reinforces the skin and kind of maintains that lipid barrier for sure. Um, sometimes moisturizers or even cleansers that contain hyaluronic acid can help to retain the moisture in the skin, but we have to remember that, um, hydration systemic wide, right? Body-wide too. So, that includes maintaining blood pressure for the heart, for the kidneys and so forth, but from a skin standpoint, those two kind of additives or ingredients are, um at least a good consideration.  

Pamela Schlembach, M.D. Absolutely, and as a dermatologist, I'm sure that people ask you, what do you think about sunscreens? I know there's a lot of mixed information out there today. Can you talk about that?  

Hung Doan, M.D., Ph.D. I'd be happy to. That's actually one of the areas that I'm most interested and passionate about. I work in the prevention side of things and so we do know, for instance, that sunscreens, especially at least SPF 30 or greater, are recommended by the FDA, recommended by the American Academy of Dermatology. They come in a variety of ingredients, and they come into two broad classes. So, there's the physical blockers which contain zinc oxide or titanium dioxide. And then there's the chemical blockers. And they're the others. They're kind of like the ones that contain avobenzone, octocrylene, oxybenzone, those are few of the sunscreen ingredients. There was a study in 2019 and a follow-up study in 2020 conducted by Food and Drug Administration scientists that showed that some sunscreen ingredients are actually found in the bloodstream when used properly. However, to contrast with that, zinc and titanium-containing products do not get absorbed or have not found in the bloodstream in any large detectable amounts from these studies, it goes to show that the Food and Drug Administration does recognize that zinc and titanium containing sunscreens are actually called GRACE, which stands for Generally Regarded as Safe and Effective. I would like to also say that we have to balance the benefit of sunscreen use with the unknown risk or unknown harms. And so, while these FDA scientists did find that there was some sunscreen products that were found in the bloodstream, we don't have long-term harm data or safety data to suggest that there is harm. We do have about 40-or 50-years' worth of really good data to support that sunscreen, consistent sunscreen use, whether physical chemical blockers, actually do prevent and slow down the progression and the attainment or the accumulation of pre-cancerous lesions called actinic keratosis. So, I still recommend sunscreen to all my patients. If there is a concern, the zinc and titanium routes are just as equally effective and, like I said, are generally regarded as safe and effective by the FDA.  

Pamela Schlembach, M.D. Thank you so much for clarifying that. I think there's a lot of discussion about should we or shouldn't we, so thank you for that.  

Hung Doan, M.D., Ph.D. Yeah.  

Pamela Schlembach, M.D. My question is, so how often should you apply sunscreen?  

Hung Doan, M.D., Ph.D. There's actually a lot of interest in that. The American Academy of Dermatology, as well as the FDA recommends at least every two hours is a sufficient amount, especially when you're out in the sun for extended periods of time. Good rule of thumb also is to avoid the peak hours between 10 and two. In Texas, maybe that kind of window would probably be eight and four, but that's just my personal preference for that too. But there's also some interest in waterproof and water-resistant sunscreens. Some may think it's a marketing ploy. From the few bits of literature that I've reviewed, there is some credence for some of the water- resistant products. But I don't think any of the commercially available products have a grading of every two hours. I think some of the products say water resistant to 80 minutes or so. Some interesting studies a few years back showed that the sunscreen can be effective almost virtually immediately, but the recommendation is to wait for about 15 to 30 minutes, especially when you're going into the water, to let the products dry. Also, if you're coming from a wet area, let's say you go in the pool, it's been about two hours and you wanna reapply, towel off. Dry a little bit, because sunscreen can very slippery and slick. How much sunscreen should you use? And the FDA again recommends an application of two grams per square centimeter. Well, what does that mean? Basically, I use the the teaspoon rule or the rule of nines from the British Association of Dermatologists, and basically, it's a teaspoon for your head and neck, scalp area as well. An Approximate teaspoon for each arm. So, that's two teaspoons for the upper extremities. One teaspoon for the front. One teaspoon for back, and two teaspoons for each leg. So, that amounts to about nine teaspoons total or about the size of a golf ball, and that's every two hours. So, I also recommend to my patients that if you buy a whole tube of sunscreen and you plan on going to the beach and all that, that's pretty much for yourself for the whole day. Which is a lot. Which is a lot.  

Pamela Schlembach, M.D. That's a lot. I wouldn't think that.  

Hung Doan, M.D., Ph.D. But that's actually how sunscreens are measured by the FDA because you measure sunscreen efficacy based on naked skin, that means unapplied skin, and then SPF applied or the sunscreen product applied skin, and then they shine a UV light on you, and then they measure how long it takes to get red. It's sort of qualitative, sort of reproducible. I've never actually witnessed a sunscreen test, but that's my understanding. And even some private agencies and, you know like, companies also ensure or validate those products too. So, it's very interesting how sunscreen is measured and recommended how to use.  

Pamela Schlembach, M.D. With that being said, there are spray sunscreens.  

Hung Doan, M.D., Ph.D. Oh, yes, the spray sunscreens.  

Pamela Schlembach, M.D. That would be hard to measure with what you just shared. So, what do you do there?  

Hung Doan, M.D., Ph.D. Absolutely. So, technically speaking, I love talking about this, by the way, I'm very excited talking about this. But sunscreen spray sunscreens, I feel, and this is sort of personal here, but I don't think you get the the same quality of application because it's variable based on how far you spray from your, from yourself and the spray can. Also, the proper application for spray sunscreens is you spray it on your skin and then you massage it in. There's no homing mechanism, no nanoparticles that could find the skin. Also, if you think about it, it's a cone of spray. So, on the areas where you don't feel the spray on your skin or that it's just not hitting, you're likely not getting sunscreen. So, you spray the top part of your forearm, but not necessarily the bottom part. The other risk is that you're also breathing in some of these aerosolized products. And there was a recent, kind of finding some articles that got published that some of the propellants were contaminated with benzene or had benzene byproducts that were found in the propellants, and there were some voluntary recalls about that. So, probably another reason to at least consider just the cream and the topical sunscreens versus the spray sunscreens.  

Pamela Schlembach, M.D. Thank you for that. That was, that's really, really interesting. And you're right, you just spray it usually in the wrong.  

Hung Doan, M.D., Ph.D. Mm-hmm.  

Pamela Schlembach, M.D. Not probably good enough.  

Hung Doan, M.D., Ph.D. Oh, and then one other thing is don't spray your face, okay? Um, you, um, technically if you read the instructions on the spray cans, you spray your hands and then you apply it to the face. So, it's no different in my opinion than just getting a lotion or cream sunscreen and just using on your face.  

Pamela Schlembach, M.D. Very good. Well, you know, a lot of times we see people now in swimming pools and they're all covered up and that's a lot different than when I was growing up. So-  

Hung Doan, M.D., Ph.D.  Yeah, from me too.  

Pamela Schlembach, M.D. So, the question I have is how effective are these, these new clothing that people are using and is there one sort of clothing that's better than another? Do you have any recommendations on that?  

Hung Doan, M.D., Ph.D. I do advocate for the sun protective clothing. I do notice in my patients who tend to fish or be on the- anglers and out in the water because you can also get reflected UV up from the water as well, that they prefer that clothing. They sweat a lot; they're not in a place where they could easily get sunscreen in the shirt or reapply for that matter. And the shirts and the clothing provide adequate sun protection. I would not go so far as to say that I'm aware of any particular studies, but I do like that there are sun protective shirts. The grading for protective factors is UPF, which is UV protective factor. It's just a broad term. I don't think there's any industry-wide consensus about what that means, unfortunately. However, from my understanding, they come in different grades. There's UPF 30, 50, and 70, and it's about the density of the weave. So, if you were to wash the clothing, you would still maintain that UV protective factor actually.  

Pamela Schlembach, M.D. Does it work year after year, or do you have to buy a new piece of clothing?  

Hung Doan, M.D., Ph.D. I think there's no rigorous or consistent understanding or suggestions that you lose that quality as it goes on. But I would expect that if there's tatters or if there is like, you could visibly see some stains or visibly see that the weave is just not intact, I think that would be a good time to buy some new clothing, the UV protective clothing. The other thing is they come in sleeves as well. So, if you're just wearing your regular clothing, which may already have UPF, you could still put on some of the sun protective sleeves, go out. I recommend that for my patients who enjoy golf or long bike rides, for instance. I haven't cracked the nut yet on cyclists because when they're going on their long rides, which is at least two hours or more, there's no good way to reapply because they're in the middle of riding. Hopefully the clothing that they wear does provide some sun protection But that has to be balanced also with the hydration issues and everything because they are literally just riding for hours on open road but wherever they're covered, that's where they'll get the UV protection.   

Pamela Schlembach, M.D. There's a lot of things online about alternatives to sunscreen. Do you have any thoughts on that?  

Hung Doan, M.D., Ph.D. Why, yes, I do actually. So, there's kind of like two things that have crossed my radar when it came to oral or alternatives to sunscreen. One is we just talked about the clothing which I completely advocate for, by the way. The other thing is actually oral sunscreen or oral SPF supporting products. There is actually no good prospective data to suggest or support that these oral products can replace sunscreen. There's just no rigorous way to prove that because it's about the comparison between non-UV exposed skin and protected skin, like we talked about how the FDA measures it. And then more importantly, I think that there are some products on the market that actually grades SPF or says orally, you take this and somehow it has SPF protection. That's not true. That is absolutely not true, and I can't support that. There may be some products on the market that would, say, protect DNA, but even then, there's laboratory testing and then there is FDA testing for human consumption and the data just are not there to this point. So, at this time, I can only recommend topical sunscreen products as well as clothing.  

Pamela Schlembach, M.D. Wear your hat.  

Hung Doan, M.D., Ph.D. And wear your hat, too, as well.  

Pamela Schlembach, M.D. And sunglasses.  

Hung Doan, M.D., Ph.D. Wonderful. Now, going for, you know, radiation treatment patients and radiation oncology patients, when it comes to just staying safe in summertime, what are your concerns about heat stroke, heat exhaustion for your patients and what have you encountered?  

Pamela Schlembach, M.D. Well, heat stroke and heat exhaustion are two very different things, but they do have some similar side effects. So, in a heat exhaustion, patients can have headaches, dizziness, nausea, muscle cramping, extreme sweating, but their skin is actually clammy. They are still alert, but they might feel weak. So, the most important thing is to get that patient out of the heat. And you can do that by putting them in the shade if there's nowhere for them to go, or if you can get them in an air-conditioned area, get a fan on them and get them drinking, because it is from salt depletion and it's generally a short-term effect of overheating. Now, heat stroke is something very serious and different, and you could have things like elevated temperature of 104, your skin is red. They're generally not sweating at that point. You can have seizures, collapse, and even death. So, it's really important for people to differentiate the two and you wanna call 911 if somebody has heat exhaustion.  

Hung Doan, M.D., Ph.D. Wow, those are actually very concerning. And sometimes, as our patients go on long trips and go into the beach and all that, they may not be aware.  

Pamela Schlembach, M.D. Right.  

Hung Doan, M.D., Ph.D. Or also just the proximity to help and safety too. So, that's very important.  

Pamela Schlembach, M.D. Absolutely, and it comes back again how you need to hydrate hydrate, hydrate. I mean it's just so important particularly in the summer and living here in the South.  

Hung Doan, M.D., Ph.D. Absolutely, I think it's so important that hydration, one, it helps us all. It's proper nourishment and all that, but it's so key to our patients. So key to just fundamentals and so simple, so simple.  

Pamela Schlembach, M.D. Absolutely.  

Hung Doan, M.D., Ph.D. I love it. So, Dr. Schlembach, here in Houston, when we think about summertime, it also brings up hurricane season. What are your recommendations for your patients?  

Pamela Schlembach, M.D. Yeah, absolutely. So, you want to, of course, follow all the normal things having to do with your safety and your home, but as a cancer patient in particular, you want make sure that you have your medications all filled and you want them in an accessible place where if you need to leave suddenly, you know where they all are, and then you want to make sure you're communicating with your medical team. I know here at MD Anderson we have a really great way of communicating with our patients through MyChart, they get text messages. And they let us know if we're gonna be open or not. You wanna make sure that, I tell patients, just open up your phone and you can have a section, there's a section called notes. And I say, write in there your medical problems, who your doctors are, what their phone numbers are, and then another page, add all your medications so they're listed. I know I have my medicines all listed on my phone.  

Hung Doan, M.D., Ph.D. Absolutely.  

Pamela Schlembach, M.D. And that way, your phone is with you all the time. And make sure that you have a charger for your phone and you can get portable chargers and make sure your phones are charged up. But those are the ways that I tell patients, you know, you wanna certainly do the regular things that they tell us on the news when a hurricane is coming, but your situation is in addition as a cancer patient, these are the things that I would like you to make sure that you have ready.  

Hung Doan, M.D., Ph.D. I appreciate that. Yeah, hurricane preparedness is very important.  

Pamela Schlembach, M.D. Absolutely. So, my question to you is, speaking on hurricanes, when we have really bad weather in Houston, a lot of times we'll have rain and then the bugs come out. So, as a dermatologist, can you tell me, how can we tell our patients what insect repellents are safe for them to use?  

Hung Doan, M.D., Ph.D. Oh this is a great question. Actually, I did a little bit of research on this, and most if not all insect repellents and pesticides are actually registered with the EPA first, and so I used the CDC and the EPA website for my references. And the key products that you know our patients should be aware of one is DEET, D-E-E-T. I think it's a long chemical name. I didn't write that down, but that's a well-known insect repellent. And so, any percentage, actually, has been shown to be safe for human use. They come in a variety of percentages from one to almost 100%. The key part is, apparently the higher the number, it's more associated with the duration or the durability of that product at repelling insects. And while not mechanistic, it's been suggested that insect repellents, including DEET either, quote-unquote, repel insects or rather make the human host undetectable to the insects. That's the key part. I think, for instance, at least abroad in Europe, the recommendation is at least 50% can have a good two-hour duration of repelling mosquitoes, which is very important here in Texas. West Nile has been detected already, so that's also certainly a good thing. It's also, DEET is also safe for use in all ages, including young children as well. Sprays are available, but especially in radiation patients, I think the consideration is that the sprays may have some alcohol in them, which can be very traumatic or irritating for the skin. So, the key part is they also come in a variety of other products like lotions and creams and so forth. So, we could use that as well. Another product that I like to talk to my patients about is picaridin, which is a pyrethroid. It's similar to, I think chemically, it's related to chrysanthemums, for whatever reason, but they have been EPA registered and also CDC recognized to be efficacious for insect repellents and that's used as a cream typically but there are sprays available.  

Pamela Schlembach, M.D. So, that's like an alternative.  

Hung Doan, M.D., Ph.D. An alternative to DEET.  

Pamela Schlembach, M.D. OK.  

Hung Doan, M.D., Ph.D. A natural product that is actually a plant-derived product, excuse me, that is actually approved or registered by the EPA is a product called lemon oil of eucalyptus. And this product, it may sound nice, but apparently it doesn't smell that nice. But it's also allowed and safe for use on humans as an insect repellent. It's more plant based too. Surprisingly, citronella as a topical like some of the sprays have not been registered by the EPA. So, that's something to take into consideration. And yet there are still other chemicals. There's one called KR3535, which is related to picaridin, actually, and is available in some preparations, and that's also safe for human use as well. Actually, of interest is that I wanted to bring up that there's also products that contain insecticides, and that includes permethrin, which on the one hand is FDA approved as a cream to use to treat scabies and some forms of lice, but actually as a spray that's commercially available without a prescription. Do not use this on the skin, however. This actually goes as a spray onto clothing and tactical gear and tents. And it actually could basically kill mosquitoes and ticks. And people should use this if they're going hiking, they're tucking in their clothing into their boots and so forth, but they could spray their clothing. What's great is at least for the clothing, it's good for a few washes. So, it's actually durable even after laundry as well, so.  

Pamela Schlembach, M.D. Nice.  

Hung Doan, M.D., Ph.D. Yeah  

Pamela Schlembach, M.D. I have another question about what if you get a sunburn? What's a good way to take care of a sunburn?  

Hung Doan, M.D., Ph.D. Well, sunburns already, it basically is the body's response to sun damage that damaged the keratinocytes. So, honestly, it's almost like a real burn. In that case, we just use aloe and just moisturizers to help support the skin. Also because of a compromised skin barrier, hydration's very important too.  

Pamela Schlembach, M.D. Do you ever recommend things like Silvadine or Mepilex?  

Hung Doan, M.D., Ph.D. For severe cases, if the patient presents to me in a timely fashion, I would actually prescribe Silvadine. Now, when we get to the higher sunburns that do blister, that do cause skin peeling because of the compromised barrier, I do use some prescription Silvadene to help support and soothe the skin, and that's always a great topical. It's used in burn patients, so we know that it helps to reduce the bacterial burden should patients suffer that because there is a compromised skin barrier, and it helps support the skin barrier as it heals itself too. And then patient needs to get themselves out of the sun, right?  

Pamela Schlembach, M.D. Right, absolutely. Do they cover up when you put on Silvadine? Do you use some sort of a barrier over that?  

Hung Doan, M.D., Ph.D. We can, yeah, absolutely, and that could be the non-adhesive gauze, or yeah, non-adhesive gauze, sometimes bandages and all that, but we have to take into consideration that because of the compromised skin barrier, any adhesives can actually be a little more irritating to the skin as well.  

Pamela Schlembach, M.D. Yes, and speaking of barriers to the skin, that's one of the problems that we run into with radiation is everybody wants to get in a swimming pool.  

Hung Doan, M.D., Ph.D. Oh, yeah.  

Pamela Schlembach, M.D. Or with the water, let's say. And so, we have conversations with our patients about that as well. And I treat a lot of breast cancer patients, and I generally say, it's fine to get the water but you have to get it in the water from your belly button down. So, we just don't want you to be sitting, soaking in chlorinated water in your breast area because sometimes you can get some skin reaction from radiation and and then we, they say, 'Well can I do other things like can I go tubing in the river or in a pond or a lake?' And I'll say we generally recommend that you don't do that because there's bacteria, microorganisms and who knows what else, so I say we want to keep your skin protected in the barrier, again it's a barrier for your body.  So, we want to make sure that's safe.  

Hung Doan, M.D., Ph.D. I absolutely agree. I support that fully. We discourage brackish waters, certainly after radiation treatment, but also, you know, in other cases, for instance, when we do skin surgeries for skin cancers and skin excisions for other various lesions, we recommend avoiding brackish water because we just don't know what's in there. For instance, even amoeba has been detected in some fresh waters, especially around here in the Gulf Coast region. So, that's certainly a concern. No effective treatments for that that we're aware of easily. Although you know get yourself to a tertiary hospital for that. And then also just even though we may think that spring waters are clean, we also have to remember that other people are in there so there's also other sources of bacteria as well as even just nature, the dirt, the brox and so forth.  

Pamela Schlembach, M.D. Yeah, so it's probably just as better to go get your sprinkler head and sprinkle yourself with cold water.  

Hung Doan, M.D., Ph.D. Absolutely, absolutely. The American Academy of Dermatology and us dermatologists also recommend the best way to reduce your risk of UV exposure and all that is seeking sunshades, so any shade structures, public parks, recreational areas, but also just staying in your house when you can and avoiding those peak hours I talked about.  

Pamela Schlembach, M.D. I agree, my patients are like, 'But it's summer, I wanna do things. I wanna be outside. Can I be outside?' And I'm like, 'Absolutely, but I'm gonna recommend that you do what I do.' I usually get up in the morning and walk early, get my nature fill, or you can do it in the evening. Those are some good times, particularly living in the South where it's so hot here and the sun shines pretty long. So, those are my recommendations as well.  

Hung Doan, M.D., Ph.D. Right, and the clothing is always quite convenient. You don't have to worry about overheating in your car and you just have like an extra set of clothes in there as well. Dr. Schlembach, thank you so much for joining me today. I thought this was a wonderful discussion for our patients.  

Pamela Schlembach, M.D. Thank you, Dr. Doan. It was my pleasure, and I just want you to know I learned a lot today as well, so I appreciate everything that you shared.  

Hung Doan, M.D., Ph.D. Thanks for listening to the Cancerwise Podcast from MD Anderson Cancer Center. If you enjoyed this episode, be sure to follow or subscribe on Apple Podcasts, Spotify, YouTube, or wherever you get your podcasts. And don't forget to comment or review. For more information or to request an appointment at MD Anderson, call 1-877-632-6789 or visit MDAnderson.org.