The People's Perspective on Medicine

How Well Do Sunscreens Work to Prevent Skin Cancer?

If you follow your dermatologist's recommendation, you do NOT go out in the sun without sunscreen. But how good is the evidence that sunscreens prevent skin cancer?

We have all been told countless times to smear on the sunscreen! The Australians even had a slogan: “Slip! Slop! Slap!” It was part of a 1981 health campaign to: “Slip on a shirt, slop on sunscreen and slap on a hat” to “stop skin cancer.” There is little doubt that sun exposure, especially in Australia, contributes to a lot of skin cancer. But do sunscreens prevent skin cancer? It’s more complicated that you might think, as this reader suggests:

What About Vitamin D?

Q. It seems to me that sunscreens may prevent burning, but I’m not sure they prevent skin cancer. The incidence of all types of skin cancer has increased since sunscreens were introduced.

I also worry that people who shun the sun completely may be missing out on vitamin D. I’ve read that this vitamin helps keep cancers (even skin cancers) from developing. Can you help with this puzzle?

The Research On Sunscreens is Confusing:

A. Consistent sunscreen use is a pillar of public health campaigns for preventing skin cancer. To answer this reader’s concerns we went searching for gold-plated evidence to support sunscreen effectiveness to prevent skin cancer. We were surprised at what we found.

Let’s Search Cochrane!

One of our first search destinations was the Cochrane Collaboration. We rely on this independent organization to evaluate a range of health strategies. Here is how the scientists describe their work:

“The main purpose of The Cochrane Collaboration is to develop systematic reviews of the strongest evidence available about healthcare interventions. Consumers and health practitioners can then work together to make the best possible decisions about health care. The reviews are published electronically within The Cochrane Library and are freely accessible in shortened versions (abstracts and consumer summaries).”

Cochrane and Sunscreens to Prevent Skin Cancer:

What we found about sunscreens to prevent skin cancer was surprisingly skimpy (Cochrane Database of Systematic Reviews, July 25, 2016).

The authors concluded:

“In this review, we assessed the effect of solar protection in preventing the occurrence of new cases of keratinocyte cancer. We only found one study that was suitable for inclusion. This was a study of sunscreens, so we were unable to assess any other forms of sun protection. The study addressed our prespecified primary outcomes, but not most of our secondary outcomes. We were unable to demonstrate from the available evidence whether sunscreen was effective for the prevention of basal cell carcinoma (BCC) or cutaneous squamous cell carcinoma (cSCC).”

What About Sunscreen to Prevent Melanoma?

The Cochrane analysis did not address the value of sunscreens to protect the skin against melanoma, the most serious form of skin cancer. So we went searching further.

We found a meta-analysis of 29 studies published in the European Journal of Dermatology (April 1, 2018).  The journal article was titled:

“Use of sunscreen and risk of melanoma and non-melanoma skin cancer: a systematic review and meta-analysis”

To our amazement this review did not show sunscreen protected people against skin cancer. The authors wrote:

“The use of sunscreen is a key component of public health campaigns for skin cancer prevention, but epidemiological studies have raised doubts on its effectiveness in the general population. This systematic review and meta-analysis aimed to assess the association between risk of skin cancer and sunscreen use.

“The cumulative evidence before the 1980s showed a relatively strong positive association between melanoma and sunscreen use (cumulative OR [odds ratio]: 2.35; 95% CI: 1.66-3.33). The strength of the association between risk of skin cancer and sunscreen use has constantly decreased since the early 1980s, and the association was no longer statistically significant from the early 1990s. While the current evidence suggests no increased risk of skin cancer related to sunscreen use, this systematic review does not confirm the expected protective benefits of sunscreen against skin cancer in the general population.”

The Man Just Bit the Dog!

This isn’t the way it is supposed to work. We would have expected a significant inverse association–the more sunscreen used, the less skin cancer.

Other Research Reviews?

One analysis does not resolve the question whether sunscreen can prevent skin cancer, even if it included 29 studies. So we went looking for other reviews. A journal that most physicians admire is the Annals of Internal Medicine. A study published on December 16, 2003 analyzed 18 studies. It was titled:

“Sunscreen use and the risk for melanoma: a quantitative review”

The authors reported:

BACKGROUND:

Originally developed to protect against sunburn, sunscreen has been assumed to prevent skin cancer. However, conflicting reports include claims that sunscreen increases risk for melanoma.

OBJECTIVE:

To examine the strength and consistency of associations between melanoma and sunscreen use in the published literature.

CONCLUSIONS:

No association was seen between melanoma and sunscreen use. Failure to control for confounding factors may explain previous reports of positive associations linking melanoma to sunscreen use. In addition, it may take decades to detect a protective association between melanoma and use of the newer formulations of sunscreens.”

It was a relief to read that the authors concluded that sunscreen use did not cause melanoma. But it was disappointing to see that they could not conclude that sunscreen could prevent skin cancer. Their last sentence, though, is very revealing. “It may take decades to detect a protective association between melanoma and use of the new formulations of sunscreens.”

Really? It has been decades since high SPF sunscreens have become available. They do a great job preventing sunburns. How is it possible that we do not have fabulous research proving that sunscreens prevent skin cancer?

We do not get it. Where’s the FDA? How come dermatologists haven’t conducted huge studies supporting their recommendations to smear on the sunscreen? Why hasn’t the NIH funded such research? Why don’t we have an answer to the question?:

Why Is Skin Cancer Going Up Despite Such Effective Sunscreens?

What Should We Do? A People’s Pharmacy Perspective:

It still makes sense to protect yourself from sunburn, which is painful as well as dangerous. Perhaps you have heard the phrase:

“Only mad dogs and Englishmen go out in the noonday sun.”

It has been attributed to an Indian proverb, Rudyard Kipling and more definitively to the songwriter, Noel Coward. He did write a song titled “Mad Dogs and Englishmen.”

Should you wish to listen to the song and read all the lyrics, here is a link to

“Mad Dogs and Englishmen”

We would go further than Noel Coward. We encourage people to stay out of direct sunlight between 10:00 am and 2:00 pm. If you do go out, follow the Australian admonition to slip on a shirt with long sleeves and slap on a protective hat. There is also specialty clothing and swimwear that provides some ultraviolet protection. Just search for sun protective clothing.

What About Sunscreen and Vitamin D?

Our reader asked a question about sunscreen and vitamin D. Sunscreen does prevent vitamin D formation in the skin. People who protect themselves from UV rays may not make adequate amounts of vitamin D. Oral supplements might be helpful.

Should you wish to find a sunscreen without oxybenzone, a suspected endocrine disruptor, you may wish to read this article:

Can You Find A Good Sunscreen Without Oxybenzone?

Share your own thoughts on sunscreen to prevent skin cancer below in the comment section. We would love to hear from dermatologists. We live in an era of evidence-based medicine. Why don’t we have really strong evidence that sunscreens prevent skin cancer? Without that research how can dermatologists be so sure that their advice is based on solid scientific evidence?

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.” .
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In looking for a safer alternative to sun blocks, I found scientific studies (just Google “silymarin + skin cancer”) indicating that topical use of silymarin (milk thistle) can help to prevent skin cancers. Silymarin cream is available online, but you have to figure out for yourself which such product(s) are the best to use–in terms of strength, etc.

The research so far appears to be basic science. For instance: https://www.ncbi.nlm.nih.gov/pubmed/27669200

At my dermatologist’s insistence (AKs & lotsa liquid nitrogen) I started using an SPF 50 topical (titanium- and zinc-based), but the only result I got was burning eyes, to the point that the bloodshot was BROWN!

I’m now just staying in from 10 or so ’til 2 or 3, wearing a broad-brim hat, & when I mow the lawn, a long-sleeve cotton twill shirt. So far, so good.

I have to agree with Tom. As kids we lived outside and played all day mostly without any T-shirts and never used sunscreen. Back in those days I never heard of a single case of skin cancer. Today it is found all over. Someone should be researching this to find the contributing factor.

Sunscreen is a chemical, and the skin will absorb chemicals into the skin and blood stream. What ever is used in the various sunscreen products I don’t want ingested into my skin as I don’t know what effects it will have on cellular structure.

Also it would seem to me that IF sunscreens provided some protection it would only be if the layer of sunscreen was thick enough to prevent UV penetration. I suspect a thin film of sunscreen will probably limit but not totally eliminate the rays from entering into your body.

Thank you for this article. As a result of reading it, I checked all our sunscreen bottles and found they claim to prevent sun burn. There are no claims regarding cancer. Since my husband has had several minor skin cancer growths removed, I researched family history. It seems our ancestors in the 1800’s who were farmers in Wisconsin and Missouri lived into old age without cancer.

They likely had adequate vitamin D. I also looked at the Linus Pauling Institute review of vitamin A. There are many different forms from both animal and plant sources, evidence of skin tumors related to retinal palmitate (a animal based form of A),and conflicting studies regarding absorption through the skin.

They also explain the various benefits of A in healthy physiology. It is required for what is called cellular immunity, the ability of individual cells to fight infections generally, as opposed to more specific antibodies. This form of immunity is known to be necessary for fighting Measles, much more than the antibodies.

It is thought the increased use of cod liver oil with it’s high A and D levels reduced death from measles by 98% a decade before the introduction of the vaccine. “Let food be your medicine”.

I’ve had multiple basal and squamous cancer on my back and basal on the top of my head that I attribute to 30 years of driving convertibles. The doctor said that even though they got all of it during the MOHS surgery, there’s still the possibility that cancer could form under the scar and they wouldn’t catch it.

I wear a hat when I go outside – I have fair skin and thin hair so a hat is crucial even though it’s hot and gives me ugly hat hair. I wear long sleeves and the heat buildup is intolerable at times. I wear sunscreen on my face at all times even with a hat, and I also take Vitamin D supplements.

I have full body exams regularly but my biggest concern is the vulnerability on the top of the head. My doctor said that having 2-3 bad burns when I was a teen and young adult contributed to the skin cancer when I was in my mid-adulthood since it can take many years to surface. I was never a sun worshipper since I burned so easily but I’ve had at least four incidents of skin cancer.

I have always been reluctant to use chemical sunscreen. I’m also concerned about the environmental effects to coral reefs. I believe Hawaii has banned some sun screens. In the past I was outdorsey, but always able to find shade. I am blessed with olive skin that doesn’t easily burn. Now I live in Florida. There is no shade on a beach. I bought inexpensive versions of the long sleeve shirts surfers wear. They are great for the beach and splashing in the ocean. They work well for biking and kayaking as well. Hats help. If I am going to have enough sun exposure to worry about burning like being out between 10 and 2 or being out for many hours without a break I use the natural zinc oxide sunscreens. Sure I look a little white and silly, but it is worth it to not pollute the environment or myself with toxic chemicals. I also think the vitamin D production is well worth the small risk of sun exposure. 50 years old. No skin cancer. Robust immune system. I haven’t had a real cold in 4 years.

I had melanoma in 1990, thankfully my husband found it early so it was only stage one. Since then, I’ve faithfully used kids SPF 50 as part of my daily routine, have regular skin check ups and followed dermatologists advice to stay out of the sun between 10-4. When gardening, I look like the quentessential southern lady with long garments and big hat LOL. At 71, I look younger and have been cancer free; truly believe my health care has helped! Saddest thing about melanoma is that I can’t donate blood or any of my body at death.

I’m 86. Grew up in Kansas. As a youth we didn’t wear a shirt to play or swim all summer. Sun burns were occasionally severe and painful particularly if we spent a day at the swimming hole or pool early in the season.

The incidence of Melanoma skin cancer has grown from 6.8 per 100,000 in 1973 to 25.2 per 100,000 in 2014. (seer.cancer.gov/star facts/html/is/melan.html)

This is the inverse of what we should have observed. I maybe cynical, but it seems to me there is a strong case to indicate sunscreen use is the cause. Nano Titanium dioxide, a frequent component of sunscreens, is a known carcinogen when exposed to uv light.

I quit using sunscreen several years ago when it became apparent to me that it is a dangerous chemical concoction that has made its creators a bunch of money. I play golf 3 times a week in Texas. I wear a brimmed hat, polo shirt and shorts. No sun screen. Cancer free!

Sunscreen

FDA should stop more than SPF 30.
Moderation is always the virtue.

One glass of 100% organic purple (Concord) grape juice plus a cup of green tea before yard work in the sun is all I need to not get sunburned anymore. Like many of your readers, I too am a fair-skinned/freckled person. The success I saw with grape juice convinced me to read up on the PubMed articles about it. Absolutely fascinating.

Recently had very informative visit with a Renal Specialist. In explaining my very low vitamin D level as shown in blood test- I have a gardening business and am in the sun many hours with no sunscreen – he explained that the far majority of folks especially in the U.S. have low vitamin D. He also explained that when you are in your senior years your body cannot convert vitamin D into a useable form as efficiently. He also explained the numerous bodily functions adversely affected by low circulating vitamin D. He started me on a supplement and told me he thinks I will feel as good as I did some years ago. After a month I can safely say that he was correct. I still work two days a week at my business though I am 70. I am noticing I can last longer and get a second-wind later in the day. ~

What if the positive correlation between sunscreen use and skin cancer were caused by overconfidence of sunscreen slappers-on so that they stayed in the sun much longer than the non-slappers-on? Did the studies include average time spent in the sun, and time of day outdoors?

Great question Isabel. We suspect that was a problem with the old sunscreens of about 20-30 years ago. They were pretty good at protecting against a burn but did not protect well against UV-A solar radiation. Those rays got through and were probably a contributor to skin cancer. Modern sunscreens protect against UV-A and UV-B to some extent…but we would still like to see excellent research establishing a skin-cancer protective effect!

I was a complete sun worshipper from about 12 years old until at least 60. I never ever used sunscreen. I have had no skin cancer (am 74 now) but I do have the skin of someone very old.

Now I cover up in long pants and mostly long sleeves just to hide the “age spots” that cover my body. I will also say that I was never sick with colds, flues or anything else during that time. I wore face make-up most of the time and even though it didn’t have sunscreen in it then, my face has much fewer spots than my arms or legs. I have had some very bad sunburns and that probably did a job on my skin.

The people I have known who had melanoma were not sunbathers and their melanoma was not in a spot that was in the sun very often (if at all). In my nonprofessional opinion I would suggest moderation as in most things, especially if you would like to wear Bermuda shorts and sleeveless tops when you are over 65.

I use sunscreen..it helps prevent age spots and the damaging effects of UV on skin. I only use 100% SPF but they say 30% is sufficient and anything stronger barely makes any difference. Using sunscreen on my face and not my arms to see if there’s a difference–there is. My face won’t tan and I like that. My arms tanned quite a bit so I’m back using sunscreen. I don’t care what the “evidence” says. Evidence-based research tends to favor the sponsors and they have been known to be wrong. All I can say is it works for me.

I have had several different skin cancers including melanoma
My Dermatologist has recommended a daily dose of niacinamide for protection.

Apparently what may be going on here is behavior related. Applying sunscreen may give folks a secure feeling being in the sun and remain in it for long periods. Between sunscreens possibly not being as effective as presumed and also washing off due to sweat and swimming, it would seem that they would be more exposed to the dangers of the sun.

I can see why it is difficult to determine the efficacy of sunscreen against skin cancers. You would have to be able to verify compliance throughout a person’s life.

I had a melanoma removed from my face 4 years ago, and have had no recurrence. I found a sunscreen that is readily available and contains NO oxybenzone. The active ingredients are nothing but titanium dioxide 3.1% and zinc oxide 4%. It is Banana Boat’s Kids Broad Spectrum SPF 50. Of course I don’t know if using this particular sunscreen is the reason I have had no recurrence of melanoma, but I do know I’m not putting questionable chemicals on my skin nor am I introducing them into lakes where I swim. I take other precautions against sunburn as well, but there are times I have to be outside all day long, and using this sunscreen has prevented all sunburn, even on my face and hands.

A quick read doesn’t indicate whether any of the reviews included longitudinal studies. Without those, there’s no way to show causality. People who use more sunscreen are likely those with lighter skin, who are also more prone to skin cancer. Your question is apt: why has there not been more serious research, including longitudinal studies?

I think that I will look further. It is sad that we have doctors who spent hundreds of thousands on education and millions are spent on machines and the truth is as old as the sages. I will look elsewhere for my health concerns.

Thanks for this. I am 76 y.o, gray now, but a redhead with freckles from the sun (they fade in fall thru spring). I am happy that when I was a young child, she preached “out of the sun between 10 and 2”…we were the only kids wearing white t-shirts in the public pool. Note: I also remember blistering painful sunburn. No serious skin cancers.

The Cochrane Collaboration has been compromised , they were the gold standard, yet no more. They just took a huge donation from Monsanto so say good-bye to them. The most knowledgeable site regarding sunscreen info is the Environmental Working Group (EWG) 30 SPF is 97% effective, 50 SPF is 98% effective and 100 SPF is 99% effective. EWG suggests not going past 50 SPF as the pay off isn’t there. They also point out how deleterious Vitamin A is in sunscreen, usually hidden. Proven to cause skin cancers.
EWG recommends sticking with ‘minerals’ for coverage. They recommend titanium dioxide & zinc oxide as the best. Another great source is an APP called D Minder that you can get for free and see the best times to go in the sun no matter where you are in the world. Let’s not forget the sun actually prevents cancer, as we need it for Vitamin D creation. Ultimately, sunscreen is common sense like sit in the shade, put on a long sleeve shirt, be awake & aware.

Kim, I wonder if you could provide your reference for the Monsanto donation to Cochrane Collaboration. I have been looking for proof of this and found the Cochrane web site list of donors. It does not mention any donation from Monsanto. I have read the works of some of the founders, like Dr Peter Gotzshe, and researchers and found them to be very opposed to industrial conflicts of interest at all levels, so your comment is very puzzling.

I use D Minder every single day. Awesome app! Essential to my personal health mission. Vitamin D from the sun or text us against parasites, viruses and fungal infections. Getting vitamin D from the sunprotects us from cancer. Getting burns is UV gone wrong. I have never gotten a burn with D Minder.

Thank you Kim, outstanding contribution. Lori

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