June 2017 - NON-MEDICATED LIFE
Editor’s Note: This is the 77th in a series on optimal diet and lifestyle to help prevent and treat disease. Any planned change in diet, exercise or treatment should be discussed with and approved by your personal physician before implementation. The help of a registered dietitian in the implementation of dietary changes is strongly recommended.
Reducing Skin Cancer Risk
By Paul E. Lemanski, MD, MS, FACP
Medicines are a mainstay of American life and the healthcare system not only because they are perceived to work by the individuals taking them, but also because their benefit may be shown by the objective assessment of scientific study. Clinical research trials have shown that some of the medicines of Western science may reduce the risk of heart attacks, strokes and cardiovascular death while others may reduce certain types of cancer.
In the first 76 installments of the Non-Medicated Life, informed diet and lifestyle have been shown to accomplish naturally for the majority of individuals, many, if not most of the benefits of medications in the prevention and treatment of chronic medical conditions. Moreover, as a medical intervention they may accomplish such benefits with fewer side effects, may reduce the number and amount of medication, and may allow actual discontinuation of medication. With certain conditions, however, lifestyle change may dramatically improve outcome when used in conjunction with medication. One such condition is skin cancer.
Skin cancer may be divided into melanoma and non-melanoma cancer. Non-melanoma skin cancers include squamous cell cancer and basal cell cancer. These cancers generally grow by direct extension and thus may be cured by surgery, although advanced squamous cell cancers may metastasize and become life threatening.
Melanoma skin cancers are by far the most dangerous. Melanoma skin cancer may appear as a dark brown to black mole with irregular border and/or variegated color. A newly appearing mole raises concern. Additionally concerning is a mole that is increasing in size or changing. Lesions over five millimeters in diameter are particularly worrisome. Such skin cancers if not caught early in their development – and at generally smaller size – may metastasize and lead to death.
Of great concern the incidence of melanoma in the general population has increased dramatically in the last 30 years. In large part this appears to be a result of increased exposure to ultraviolet (UV) light. More specifically melanomas are caused by UVB or the part of the UV spectrum causing sunburn, and to a lesser extent by UVA or the part of the spectrum that penetrates to deeper skin layers. The increased exposure is in turn contributed to by the perception that being tanned improves one’s attractiveness and is a sign of health.
The evidence implicating UV light includes: UVB exposure can induce melanoma in human skin grafted onto mice; psoriasis patients treated with the drug psoralen and UVA showed evidence of a significant increase in melanoma; users of indoor tanning beds (UVA) experience a 20 percent increase in melanoma with a 40 percent increase risk for those reporting first use before age 35; Australia’s national campaign to reduce sun exposure has been associated with reduced melanoma incidence of five percent per year in men and women aged 15-24.
The reduction in UVA and UVB exposure is most critical for those at highest risk. Those who are fair skinned have higher rates of melanoma. Indeed, the incidence of melanoma is 20 times greater in white skinned individuals than those who are black skinned. Moreover, a history of five or more blistering sunburns in childhood and/or adolescence more than doubles the risk for melanoma. Likewise, those individuals with more numerous benign moles also are at increased risk.
Lifestyle strategies for reducing UV exposure include the avoidance of midday sun (between 10am and 2pm), the use of sun protective clothing including a hat, and the appropriate use of sunscreens. Clothing should have tightly woven fabric that is darker in color (e.g. denim), but when you are uncertain it may be best to rely on commercially available clothing with designated ultraviolet protection factor (UPF) built into the fabric (sunprecautions.com). Additionally, hats should have a six-inch brim to give full face and neck protection.
Sunscreens are not a substitute for the lifestyle choices of appropriate clothing and sun avoidance. Nevertheless, there is evidence from randomized trials that sunscreens can prevent the development of premalignant skin lesions, squamous cell skin cancer and melanoma. A randomized trial of broad-spectrum sunscreens over ten years in Australia showed a 50 percent reduction in melanomas and a 40 percent reduction in squamous cell skin cancer.
Broad-spectrum sunscreens should reduce both UVB and UVA through a combination of UV absorption and physical blocking. Generally, a minimum SPF of 15 is needed, but the higher the SPF the better especially for those at higher risk. Sunscreen should be applied about 30 minutes before sun exposure.
To provide effective protection sunscreens must be applied in the proper amounts to all sun exposed skin and then reapplied periodically. For example, a typical adult at the beach would require a bit more than one ounce or nine teaspoons of sunscreen applied as follows: one teaspoon applied to the face and neck, one teaspoon to the front of torso and one teaspoon to the back, one teaspoon to each arm, and two teaspoons to each leg.
Reapplication every two hours is required and if excessive sweating and/or water sports are anticipated, then reapplication is required periodically during and after activity. Generally, water resistant sunscreens will maintain SPF for only 40 minutes of water sports, after which reapplication is required.
Those individuals who value the appearance of a tan should alternatively consider the use of self-tanning agents. These products can produce a very cosmetically acceptable tan at low risk when applied to the skin by applicator or hand. Spray tans may also be safe provided there is no inhalation of aerosolized tanning droplets. It is important to note that self-tanners do not protect against sunburn or UV damage to skin. The same precautions should be taken after self-tanners as you would use to protect normal skin from UV.
In summary, skin cancer risk may be maximally minimized by a combination of lifestyle choices and proper application of topical medication. Lifestyle choices should be adjusted to individual skin cancer risk and include midday sun avoidance, the use of clothing with an appropriately designated UPF, and the use of an adequately protective hat. Sunscreens should have broad spectrum UVA/UVB protection, should be water resistant, should have an SPF of at least 15 and preferably 30, and should be applied 30 minutes before sun exposure in an appropriate amount and reapplied periodically.
The combination of prudent lifestyle choices and topical medicinal protection will allow the enjoyment of the great outdoors while minimizing the risk of a potentially life threatening cancer.
Paul E. Lemanski, MD, MS, FACP (firstname.lastname@example.org) is a board certified internist at the Center for Preventive Medicine, CapitalCare Medical Group in Albany. He is a medical director of the Department of Community Medicine and Population Health at CapitalCare Medical Group. Paul has a master’s degree in human nutrition. He is an assistant clinical professor of medicine at Albany Medical College, and a fellow of the American College of Physicians.