Summer Sun Exposure and Risk of Acquiring Melanomas

"Non-melanoma skin cancers can appear as non-healing scabs or pinkish skin growths."

"While basal cell carcinoma doesn't tend to be lethal, it does need treatment at an early stage to increase the chances of cure and minimize the cosmetic and functional impact of treatment."

"Classically, melanomas would appear as a dark or pigmented spot in the skin. However, they can sometimes present as pink, flat areas where the diagnosis is not immediately obvious." 

"They usually occur in sun-exposed skin but can also occur in parts of the body which are usually covered up, as well as under fingernails or toenails and in the eye."

Jenny Noble, U.K. clinician 

 

"Just a simple surgery will take care of them."

"If one side is much bigger than the other, then that's asymmetry. If the border is broken in some places or the colour is very different -- either a lot lighter or darker -- than the other moles you have on your body, then those are warning signs."

"Finally when it comes to the size, most moles should not be larger than half a centimetre, like the size of a pencil eraser. If it's bigger than that, you should probably have it seen by a dermatologist."

Adil Daug, director of melanoma clinical research, UCSF Helen Diller Family Comprehensive Cancer Center, United Kingdom

"They [Lentigo maligna melanomas] evolve much more slowly than other forms of melanoma."

"This presents as an enlarging, asymmetrical lesion with areas of black pigment within brown patches."

"It's not easy to see from a patient's perspective, and due to the delay, it has the worst prognosis of them all."

Christian Aldridge, consultant dermatologist

Rates of melanoma skin cancer more than doubled in the UK over the past 30 years Credit: getty

Experts believe that with warmer weather trends in climate change activities, the risk of melanoma will increase. A risk that could be mitigated by sensible precautions such as remaining in shaded areas between 11 a.m. and 3 p.m., wearing a broad-brimmed sun hat, and UV-protected sunglasses. Sunscreen should be reapplied frequently, and should be at least factor 30. The good news: most melanomas are not cancerous.

The most common form of cancerous melanoma is basal cell carcinoma, a slow-growing skin cancer that tends not spread. Squamous cell carcinomas and Merkel cell carcinomas considered non-melanoma have a more serious nature with their ability to spread to lymph nodes and other organs. Most non-melanoma skin cancers have a straightforward treatment; simple surgery.

There are four main subtypes of malignant melanomas, with superficial spreading melanomas starting off by growing along the top layer of the skin, the most common. Followed by nodular melanoma, representing roughly 15 percent of cases, the most aggressive form of the disease, able to grow faster than other subtypes. It more commonly afflicts people over age 65 and those of light complexion, tending to appear like a bump or flat lesion rising firm, and above the skin's surface.

Usually, Lentigo maligna melanomas form on the face, ears or neck of those with sun-damaged skin, frequently lending a blotchy appearance; sometimes tending to be confused with more benign skin damage. The most common melanoma in people of Black or Asian ethnicities is Acral melanoma, appearing on the palms of the hands, soles of the feet, or under fingernails or toenails. 

Women under 50 are more commonly targeted by melanoma than are men, one of the most common cancers for women of that age group. In later life, however, the prevalence switches. Men aged 65 become twice as likely to have melanoma, while men age 80 are three times as likely to develop the cancer, according to the American Academy of Dermatology. Early detection is crucial, before the cancer spreads deeper into the skin.

Experts in melanoma make reference to what is known in their specialty as the ABCD rule; where A means Asymmetry, B = Border Irregularity, C = Colour, and D = Diameter; in identifying whether a spot of discolouration on the skin might be cancerous.

Aside from direct exposure to the sun as an avoidance measure, evidence is emerging that taking vitamin D supplements may help to reduce melanoma risk. A Finnish study indicated that adults at a higher risk of skin cancer who took vitamin D tablets were less likely to have the disease. It is particularly important for people with either a family background of melanoma, a fair skin tone, or past use of indoor sunbeds, to be vigilant.

"Being deficient in vitamin D has been associated with thicker melanomas at diagnosis, and people are also more likely to suffer a recurrence of their cancer."

"We suggest taking the recommended dose, which is 10 micrograms of vitamin D supplements a day."

"If it hasn't spread, and it's caught at the earliest stage, then cure rates lie between 80 and 100 percent, usually just by surgery, without the need for chemotherapy or immunotherapy."

Chris Bakal, Institute of Cancer Research, London

Vitamin D tablets and pills.  (AP Photo/Mark Lennihan)

Vitamin D Supplementation

"Numerous studies within the last twenty years have linked vitamin D deficiency or insufficiency to various types of cancer, Alzheimer's disease, Type 2 diabetes, heart disease, pregnancy complications and more."
Dan NEwton, molecular biologist, research scientist, Medical University of South Carolina

"We are starting to see some studies show that vitamin D doesn't have a benefit, even for bone health. However, these studies are in people who have generally good vitamin D blood levels."
"It's not surprising that giving them more of a nutrient they already have enough of doesn't lead to better health outcomes."
James Fleet, professor, nutrition science, Purdue University

"Overall, the clinical trial research has shown that there are some benefits of vitamin D supplementation, but they are more limited than what was originally proposed."
"A few years ago, people believed that vitamin D was a panacea that could prevent every major chronic disease."
"This may be [why the VITAL trial failed to link vitamin D supplementation to a reduction in heart disease or stroke risk] because the amount of vitamin D needed for heart health is relatively modest to moderate, similar to the amount needed for bone health and already achieved by many without taking supplements. For cancer reduction, there may be benefits with larger doses."
"We found a strongly significant reduction in cancer death of 13 percent across the five trials, which included VITAL."
JoAnn Manson, chief, division of preventive medicine at Brigham and Women's Hospital, Harvard Medical School professor, lead author, VITAL study

According to a 2015 report published in the Journal of the American Medical Association, 2012 saw a fourfold increase in vitamin D supplementation by American adults as compared to a decade earlier. This, in recognition of the generally low dietary intake of vitamin D linked to studies widely publicized during that time suggesting its intake could prevent a large and varied types of chronic diseases.

More latterly, uncertainty relating to vitamin D's usefulness based on two recently published studies, has arisen; the first a meta-analysis published in The Lancet Diabetes & Endocrinology, suggesting that vitamin D supplemental intake has not been seen to reduce the risk of falls and fractures, nor has it be understood to have led to clinically significant improvement in bone mineral density.

The Vitamin D and Omega-3 Trial, also referred to as VITAL, represents the second study which focused on whether taking 2,000 international units (IU) of vitamin D daily for men over 40 and women over 55 might prevent cancer and cardiovascular disease over five years. This was a randomized control trial of over 25,000 American participants.

The finding of the report was that "supplementation with vitamin D did not result in a lower incidence of invasive cancer or cardiovascular events than did a placebo". Vitamin D is required for absorption of calcium and phosphorus into bones and teeth, which made it a recognized hormone promoted for its bone health facilitation -- since with a lack of sufficient vitamin D, calcium leaches from bones, resulting in loss of bone strength which can in turn lead to rickets in children and osteomalacia (softening of the bones) or osteoporosis in mature people.

In the Lancet study, only six percent of the 81 trials the analysis depended upon for its conclusion represented people with vitamin D deficiency. The conclusion in view of this fact represents an oversimplification of the trial results. Dr. Manson points out that the reasons her VITAL trial failed to link vitamin D supplementation clearly to a reduction heart disease or stroke risk may be attributable to many causes. She and her colleagues published a meta-analysis of vitamin D supplements linked to health outcomes in the Annals of Oncology. In the studies they interpreted, the dosages of vitamin D went from 833 to 2,000 IU daily.

Cancer develops over several decades, and many of the studies had fewer than five years of followup, pointed out Dr. Manson. It was therefore not to be expected that their study demonstrated that the development of cancer was not statistically at variance for the vitamin D group, versus the control group in their meta-analysis.  The recommended amount of vitamin D from diet and supplements based on bone health search has yet to be set by the National Academy of Medicine.

Should anyone consume three ounces of salmon twice weekly, have a cup of milk and two eggs daily, that would amount to 330 IU of vitamin D each day. Whereas the current recommendations are 400 IU of vitamin D for infants, 600 IU for men and women ages one to 70 years, and 800 IU for adults 71 or older. The human body can synthesize vitamin D with exposure to sun, but the Dietary Reference Intakes for vitamin D make the assumption that most people limit their direct exposure to the sun.

Aside from the fact that sun exposure is mostly seasonal, most people spend most of their time indoors; many people live at northern latitudes and see less sun in their daily lives; and those that do experience frequent sun exposure, most likely use sun protection lotions or clothing cover-ups to reduce skin cancer risks.