Check Your Skin Cancer & Sun Safety Knowledge With This Derm Expert

May 15, 2024
A senior woman with short gray hair holds a surf board over her head on a sunny beach

Stock photo posed by model, sourced by Getty Images

Are you applying enough sunscreen before you head outdoors? "It's a lot more than people realize," says dermatologist Vishal Anil Patel, M.D. Use this Q&A to brush up on your knowledge about skin cancer, prevention & protection ― including just how much sunscreen you should be using.


Skin cancer is the most common cancer in the United States today, accounting for about half of all cancers. Thanks to public awareness campaigns in recent decades, we are more knowledgeable about skin cancer prevention and sun safety than ever before. Still, many of us have lingering questions about everything from risk factors to screening recommendations to proper sunscreen application. 

Have you wondered: 

  • Should I get skin cancer screening? 
  • Can just one sunburn increase my risk of skin cancer? 
  • Is skin cancer curable?
  • Does skin cancer run in the family?
  • Can I use last year’s bottle of sunscreen? 

To get the answers to these and other common questions, we spoke with Vishal Anil Patel, M.D., Director of Cutaneous Oncology at the George Washington (GW) Cancer Center and Director of Dermatologic Surgery in GW’s Department of Dermatology. 

Here's what to know:


How does the sun play a role in the development of skin cancer? Are there other causes of skin cancer besides the sun?


Dr. Patel: Sun is a carcinogenic exposure. But there are also other carcinogenic agents that can cause skin cancer, like arsenic or even a virus like HPV (human papilloma virus). UV radiation is the most common and the most prevalent cause today.

Globally, we have a positive and a negative relationship with the sun. We all love to do stuff in the sun, but sometimes we consume it too much. We have a sun-worshipping culture, and that exposure is additive over time. So, while the sun can cause harm, you can modify your behavior to reduce your exposure risk now and going forward.

The most common types of skin cancer are non-melanoma skin cancers, and those are caused by long-term, chronic sun exposure. So, it can be decades before you develop these malignancies. 

There are other causes of skin cancer, as well ― genetic predispositions, and some medications. There are medications that lower or alter your immune system. We have so many new medications that can control your immune system, to a degree, for overactive immune systems. These chronic medications that people take ― some of them increase your risk of skin cancer. If we are artificially hampering your immune system, that can increase your risk. There are even blood pressure medications and other medications that can make you more sensitive to the sun.


Can just one sunburn increase someone’s risk of skin cancer?


Dr. Patel: Yes. Intense sunburns, especially at an earlier age, increase your risk, especially of melanoma. There is no such thing as a healthy tan ― it’s a sign that your skin is seeing UV radiation and is responding to it. It’s a marker that it’s seeing more damage than it would like. So, people who don’t blister, don’t burn, but tan a lot, [will] begin to see the effects of that. Suntans will cause you to prematurely age. It’s all on the same continuum. And that damage is variable — you can get just one sunburn and that increases your risk [or] have low levels of underlying damage over time, so your risk of non-melanoma goes up.

I tell patients you can eat a terribly high-fat meal just once, and it increases your risk of high cholesterol temporarily, or you can have unhealthy eating over time and this could increase your cholesterol. 

The same analogy works with sun exposure. Just like with everything in this world, moderation and protection is key. We try to moderate how much sugar and fat is in our diet. With the sun, we should try to moderate it too. Don’t play tennis or golf at noon. If you have to be outside, try to do your activities earlier or later. Wear sun-protective clothing. Reapply sunscreen because it wears off every 2 hours or so. Get under the tree or an umbrella, do something active, and then reapply sunscreen and take a break.


"Tanning is your body’s way of reacting to UV radiation. The skin cells are reacting to the sun and there is localized damage that is potentially occurring."

― Dr. Vishal A. Patel

Can skin cancer be inherited?


Dr. Patel: Melanoma has a much more genetic component to it [than non-melanoma]. There’s much more of a driver to it with known targeted genes. 

We think about melanoma in subgroups ― there are ones that are driven by mutations that were acquired from sun damage only, and there are ones that are due to family history and are genetically predisposed. 

The genetically predisposed ones occur when 2 or more family members on one side have invasive melanoma. That’s when we think there is a specific genetic component to it.


Discover More About Inherited Cancers

Where is the most common place to find skin cancer?


Dr. Patel: For about 85% of non-melanoma skin cancers, the most common places are on sun-exposed areas like the head and neck, forearms, and hands. 

For melanomas, they are also on sun-exposed areas, generally, but also can be anywhere on the body. If it’s genetic, it can be on an area that hasn’t seen sun damage.

Is skin cancer easy to treat and cure?


Dr. Patel: We like to start by saying that the lower risk skin cancers can be treated well when caught early. They have different risk profiles, so we have different treatment options. 

The non-melanoma skin cancers can be treated in a variety of ways, through surgical and nonsurgical options. They generally have high cure rates when cut out completely. 

As a whole, skin cancers do really well when managed early on. This includes melanoma as well. But even some melanomas that are caught and treated earlier can have a risk of the cancer spreading or causing death. But that risk is low, so early treatment is best for any skin cancer.


Find Out More About Skin Cancer Treatment Options



Dr. Patel: We don’t have clear skin cancer screening guidelines because there isn’t clear evidence about how many lifesaving benefits it has. The U.S. Preventive Services Task Force does not recommend skin cancer screening for the general population because it can lead to unnecessary biopsies and unnecessary treatment.

It’s an individualized risk stratification* that we like to consider. Most patients should get risk stratified once by a dermatologist and discuss if and what frequency you might need to be seen for skin cancer screening. If you are at high risk, you should probably get screened at different (more increased) frequencies.

*Editor’s Note: Risk stratification is a practice healthcare providers use to assign patients risk levels, from low to high, for specific conditions. A person’s risk status for a condition depends on individual factors like medical history.

"We recommend that you get used to looking at your skin once a month and get used to where all your moles and spots are. ... If you notice something change or a new growth, you should consider having that evaluated more closely."

― Dr. Vishal A. Patel


Can doing monthly skin checks at home be helpful for anyone to do, regardless of their risk level for skin cancer?


Dr. Patel: Yes, doing self-screening at home can be one of the most effective ways to find skin cancer. In fact, self-screening has been shown to be almost as effective or even more effective than seeing a dermatologist in certain scenarios. This is because you are considering the history of the way your skin looks and not just how it looks at one point in time when you go to see the doctor.

Generally speaking, we recommend that you get used to looking at your skin once a month and get used to where all your moles and spots are. Get used to how they look. And if you do that each month and regularly, our brains and eyes pick up changes or new spots. If you notice something change or a new growth, you should consider having that evaluated more closely.


Here’s What to Look For When Doing Monthly Skin Checks

Practicing sun safety, including wearing sunscreen on both cloudy and sunny days, is one of the most important ways people can lower their risk of skin cancer. There are many sunscreen products available in a wide range of SPF values, from 6 to 100. 
What should people look for when choosing a sunscreen?


Dr. Patel: The first thing I say is pick one that you like to put on ― one that feels good, that’s not annoying. Some have moisturizers; there are some that have make up. There are chemical and mineral sunscreens. See what is easy to apply and feels comfortable, whether it’s on your face, body, or whatnot. You have to do a little trial and error. I tell patients if you want the easiest one, go for the kid’s or baby version, because they are gentler and they are mineral-based.

The second point I say is that the SPF number is difficult to fully understand. It’s a strength and a duration. But in general, the higher the number, the longer it is going to work ― it’s a burn-ratio factor.* 

What I tell people is you want to have at least SPF 30, and 50 or above is best. The incremental effect after that is small. But if you see sunscreen with SPF 80 on sale, you might as well get the 80. Make sure that’s its broad-spectrum to get skin protection against both UVA and UVB rays. If you do that, then you should be in good shape.

*Editor’s Note: SPF (sun protection factor) is a measure of how long it takes UV radiation to burn skin with a sunscreen product vs. the time it would take without the sunscreen (Skin Cancer Foundation)


UVB vs UVA: What’s the Difference?

The sun emits two types of UV (ultraviolet) light that can harm the skin. UVB light affects the outer layers, causing sunburn. UVA light has a longer wavelength and reaches deeper layers of the skin. Over time, UVA exposure can cause premature skin aging. Learn more about UV radiation

As we prepare for outdoor activities and beach vacations this summer, some of us might be tempted to dig out our old bottles of sunscreen from last year, or previous years. 
Does SPF lose effectiveness after it expires?


Dr. Patel: Expiration dates are meant to be a safety point. That shelf life is that’s its optimally working to that point. If it’s a few months expired, it’s probably totally fine. If you realize that it’s expired, you can use it or mix it with [new sunscreen] so you can stretch it. Usually after 3 months is my cutoff ― that’s when I know the value is going down, and beyond 6 months there certainly will not be value. 

But the real question is, if you are going to be getting more anyway, why don’t you just make the move to [a new bottle]? That is always better and recommended, but if you are in a bind and only have one to use that is a month or two expired, that is better than not using anything at all.  

The other thing people miss is underutilizing the amount of sunscreen you need. It’s a lot more than people realize. You need one shot glass amount to apply to your whole body. You split that up per area — your torso is one area, your legs and your arms are other areas. The ineffectiveness of sunscreen is usually due to incomplete application. 

There are different myths about skin cancer and its prevention. What is one common myth you can bust now?


Dr. Patel: We always hear that myth about getting a healthy tan or starting your sunny season off with a base layer of skin hardening, so to speak. That’s really a myth. Tanning is your body’s way of reacting to UV radiation. The skin cells are reacting to the sun and there is localized damage that is potentially occurring. The myth that getting a tan is healthy for your skin is something people should disregard.


About Vishal A. Patel
Dr. Vishal A. Patel is an Associate Professor of Dermatology and Associate Professor of Medicine/Oncology at the George Washington University School of Medicine & Health Sciences. He serves as the Director of Cutaneous Oncology at the GW Cancer Center and the Director of Dermatologic Surgery at the GW Department of Dermatology. He is a board-certified dermatologist as well as a fellowship trained and board-certified micrographic dermatologic surgeon who specializes in cutaneous oncology and reconstructive surgery, including the medical and surgical management of melanoma, cutaneous squamous cell and basal cell carcinomas and Merkel cell carcinoma.