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and Other Skin Cancers
Anthony Chapdelaine, Jr., MD, MSPH, Exec. Dir./Sec.*
Mole (nevus) count is the most important risk factor for melanoma skin cancer (the skin cancer type most likely to cause death).1
A recent British study of nearly 4000 female twins determined that having more than 11 moles on the right arm made it highly likely of having more than 100 moles on the body.1 In the past scientists found that the higher the mole count the greater the risk of melanoma skin cancer (especially important when a close relative had melanoma skin cancer).
Dr. Knight, health information manager at non-profit Cancer Research UK points out that although a useful tool for screening, fewer than half of melanomas come from moles.10 Dr. Knight says that for men moles tend to be on the trunk and for women on the legs (although this study found them in slightly greater numbers on the arms for women). 1, 2
- If a mole is suspicious (change in size, color or shape or feel) get it checked by a doctor
- Ultraviolet light (which is primarily UVA) from tanning beds increases the risk for all three skin cancer types (squamous cell, basal cell, melanoma). The highest risk is for people who start using tanning beds before age 30 which increasses the risk of skin cancer by 75%.2, 3 Vitamin D3 levels (created in the skin from the UVB ultraviolet fraction of sunlight) offers protection against all cancers including skin cancer. If you can’t or won’t go in the sun, take Vitamin D3 (cholecalciferol) supplement and have blood tested at least annually to make sure your level is above 80.
- Other factors which can increase melanoma risk (and should be screened by a dermatologist at least once): fair skin and red or blonde hair (dark skin gives some, but not total, protection); multiple freckles; tanning from infrequent sun exposure (indoor work or on vacation) are at greater risk than frequent exposure (outdoor work); sunburn twice or more at anytime; previous melanoma or non-melanoma skin cancer; lowered immunity; men with higher body-mass-index2
- A study published in 2016 shows that a moderate (one to three cups daily) consumption of filtered coffee can reduce the occurrence of malignant melanoma.4
Alcohol consumption is a known risk factor for sunburn, but also for malignant melanoma skin cancer, and probably for the other types of skin cancer (basal cell, squamous cell).5-7
The greater the quantity of alcohol consumed daily, the greater the risk for other cancers as well (oral cavity and pharynx, esophagus, colorectum, liver, larynx, female breast, pancreas, prostate).5
Evidence suggests that alcohol increases the risk for skin cancer, (and likely other cancers) by decreasing antioxidant levels. In one study, orange juice (containing the antioxidant carotene which is found in many fruits and vegetables, especially orange-colored) kept alcohol from decreasing the concentration of skin carotene and the researchers concluded that it therefore should protect against skin cancer.7
Another study suggested that citrus consumption made the skin more sensitive to ultraviolet light and thus might increase the risk for malignant melanoma,8 however, this study was criticized as having too many problems and, unless additional studies confirm this result, consuming citrus is not considered a risk factor for skin cancer.9
Besides consuming plenty of organic fruit and vegetables, and limiting alcohol intake, work with a knowledgeable health professional to determine which antioxidant supplements you should take routinely.
Melanoma Risk Associated with Frequent Grapefruit and Orange Consumption
A 25-year study involving over 100,000 health professionals evaluated whether consumption of oranges and grapefruit increased risk of melanoma skin cancer. Risk for melanoma increased 25% for those eating oranges or grapefruits more than twice a week compared with those who consumed these citrus once a week or less. The largest increased risk of melanoma (41%) occurred for those eating grapefruit three or more times a week compared with those never eating grapefruit. One mechanism: chemicals in these two citrus act as “photosensitizers” making the skin more sensitive to sunlight. Therefore, the researchers suggest to minimize this problem, limit sun exposure for a few hours after consuming citrus. The researchers cautioned that these findings are only suggestive and may not apply to everybody and also require further studies.10
Frequent Brief Skin Sun-exposures Cause Non-melanomas; A Few Sunburns Cause Melanoma
Cumulative short-term (less than thirty minutes) of daily sun exposure (also depending on the time of day, 10 am until 2 pm being the most intense exposure) increases the risk for the usually non-lethal (although potentially disfiguring) basal cell and squamous cell skin cancers. Occasional intense exposures that cause sunburn increase the risk for malignant melanoma.
Immune-Suppressing Drugs used for Auto-Immune Disease and Transplants ncreases Skin Cancer Risk
Drugs which suppress the immune system, such as those used after organ transplants to prevent rejection can increase melanoma two-fold and squamous cell cancer 100-fold, with increases in basal and merkel cell carcinomas falling in between.11 Common drugs used to suppress symptoms found in so-called “autoimmune diseases” (rheumatoid arthritis, Crohn’s Disease, lupus, etc.) have likewise been found to increase the risk for non-melanoma skin cancers. These drugs and the medical conditions themselves make cancer-related immune surveillance (screening) more difficult.12
Green Tea Helps Prevent Non-melanoma Skin Cancers
A recent review showed that stimulating interleukin (IL) 12 is the major mechanism by which green tea polyphenols rapidly repair sun-damaged skin DNA.13
* The Coalition for Advanced Cancer Treatment and Prevention a project of The National Fund for Alternative Medicine
- Ribero S, Zugna D, et al, “Prediction of High Naevus Count in a Healthy U.K. Population to Estimate Melanoma Risk,” Br J Dermatol, 2016, 174, Pgs 312–318, doi:10.1111/bjd.14216.
- International Agency for Research on Cancer, IARC, Lyon, France, “Beauty and the Beast,” The Lancet Oncology, 2009 Sept, 10(9), Pg 835.
- Lukic M, Jared M, et al, “Coffee Consumption and the Risk of Malignant Melanoma in the Norwegian Women and Cancer (NOWAC) Study,” BMC Cancer, 2016 Jul, 16(1), Pg 562.
- Bagnardi V, Rota M, et al, “Alcohol Consumption and Site-specific Cancer Risk: A Comprehensive Dose-response Meta-analysis,”Br J Cancer, 2015 Feb, 112(3), Pgs 580-593.
- Rota M, Pasquali E, et al, “Alcohol Drinking and Cutaneous Melanoma Risk: A Systematic Review and Dose-response Meta-analysis,”Br J Dermatol, 2014 May, 170(5), Pgs 1021-1028.
- Darvin ME et al, “Alcohol Consumption Decreases the Protection Efficiency of the Antioxidant Network and Increases the Risk of Sunburn in the Human Skin,”Skin Pharmacol Physiol, 2013, 26(1), Pgs 45-51.
- Wu S, Han J, et al, “Citrus Consumption and Risk of Cutaneous Malignant Melanoma,”J Clin Oncol, 2015 Aug, 33(23), Pgs 2500-2510.
- Berwick M, “Dietary Advice for Melanoma: Not Ready for Prime Time,”J Clin Oncol, 2015 Aug, 33(23), Pgs 2487-2490.
- Shaowei Wu,Jiali Han, et al, “Citrus Consumption and Risk of Cutaneous Malignant Melanoma,” J Clin Oncol, 2015 Aug, 33(23), Pgs 2500-2508, doi:10.1200/JCO.2014.57.4111.
- Robbins H, et al, “After a Transplant: New Dangers,” http://www.skincancer.org/prevention/are-you-at-risk/transplants
- Scott F, et al, “Risk of NonmelanomaSkin Cancer Associated With the Use of Immunosuppressant and Biologic Agents in Patients With a History of Autoimmune Disease and Nonmelanoma Skin Cancer,” JAMA Dermatol, 2016 Feb, 152(2), Pgs 164-172, http://jamanetwork.com/journals/jamadermatology/article-abstract/2466923
- Katiyar S, “Green Tea Prevents Non-melanoma Skin Cancer by Enhancing DNA Repair,” Arch Biochem Biophys, 2011 Apr 15, 508(2), Pgs 152–158.