Now that the season is in full swing, readers of this column are likely spending more and more time outside training for and racing in triathlons. As far as their health is concerned, this is a very positive thing. Exercise confers numerous health benefits and every individual who partakes in an exercise program will reap the rewards. However, it is also a good idea to remain vigilant for the often overlooked and underappreciated risks of just such a program. Certainly, the risks of injury from a bicycle or running accident are well described and while not first and foremost in every triathlete’s mind they are acknowledged. But, other risks that may not be perceived because of their long term nature also exist and should be given at least some respect. This article deals with one of those, the risk of developing skin cancer.Skin cancer is the most common form of cancer in the United States. Almost 50% of all cancers diagnosed each year are some type of skin cancer. Fortunately, the vast majority of skin cancers are benign. However, as the incidence of all skin cancers is rising so to is that of the most dangerous form of skin cancer; melanoma.Like all cancers, skin cancer arises when the DNA in a cell becomes damaged and cannot be repaired. As a result of this damage, the cell begins to grow and divide uncontrollably. Skin cancers are named for the cell line that becomes cancerous. Nearly all cases of skin cancer are one of the following three types:Basal cell carcinoma (BCC)The most common form of skin cancer, BCCs are also the most common type of cancer worldwide. In the United States alone, almost one million cases of BCC are diagnosed annually. BCC derives from the basal cells that are at the deepest part of the skin layer. As the root cause of BCC is cell damage caused by solar radiation, BCC is almost always found in sun-exposed areas. The face, scalp and hands are the most common locations for BCC making early detection the norm. BCC is a very slow growing cancer and almost never metastasizes, (spreads to other organs or parts of the body). Treatment consists of surgical excision and is uniformly curative.Squamous Cell Cancer (SCC)Comprising approximately 16% of skin cancers, SCC derives from the squamous cells that are in the uppermost layer of the skin. Like BCC, SCC also arises after sun damage and so is most commonly found in sun-exposed areas. However, SCC can occur anywhere on the skin including in the mucous membranes of the mouth and genitalia. SCC can have varying appearances. Most often it appears as a crusted or scaly area of skin with a red inflamed base that resembles a non-healing ulcer, or crusted-over patch of skin. SCC can metastasize and of the almost two hundred thousand people diagnosed in the U.S. each year, nearly 10% will die from the disease.MelanomaMelanoma arises from melanocytes; skin cells that secrete melanin that gives color to the skin. Darker skinned people have more melanocytes and thus more melanin. When fair skinned people are exposed to the sun for periods of time, more melanin is secreted in an effort to protect against the harmful ultraviolet radiation that damages skin cells. The result is a darkening or tanning of the skin. Melanoma accounts for only four percent of skin cancers but for more than 80% of skin cancer deaths. Melanoma almost always begins in moles, areas of concentrated melanocytes. When detected early, melanoma has a 95% cure rate. However, once this form of cancer metastasizes it is nearly impossible to treat. Protecting against skin cancerAs noted above, the most important risk factor for all forms of skin cancer is prolonged sun exposure. This is particularly true in fair skinned people who have less protective melanin. Both BCC and SCC are seen more frequently in light skinned people but melanoma is seen equally in people of all skin types. While it is true that family history plays a role in a small minority of melanomas, sun exposure still affords the most risk.The best measure of protection for skin cancer then is to avoid unprotected sun exposure. This is particularly true in summer months, at altitude, in areas closer to the equator and during mid-day when the sun is strongest. If you must do your training at times or in locations when and where sun exposure is strongest, wearing full-length clothing or sun screen is strongly encouraged. Sun screen with a protection factor (SPF) of 30 or more is recommended and waterproof sun screens are advised for use during exercise and especially when swimming.Once skin cancer of any form develops, early detection and therapy is critical to ensure a complete cure. Any new or suspicious lesion on the skin should be brought to the attention of your physician as soon as possible. Because melanoma often arises insidiously within pre-existing moles, it is important to survey any moles regularly. A mole that changes in size, shape or color is a potential melanoma as are moles that bleed or itch. A simple way to differentiate moles from melanomas is to remember the ABCD rule. As opposed to moles, melanomas have Asymmetrical shapes, irregular Borders, uneven Color and a Diameter larger than that of a pencil eraser, (about 5mm).Training in the sun is an enjoyable benefit of leading an active lifestyle and I am in no way suggesting that this should be curtailed. Rather, I urge you to remember to schedule an extra few minutes at the beginning of every outdoor workout, swimming included, in order to apply a generous coat of sun screen. This activity won’t add anything to the quality of your performance but it may allow you to enjoy many more years of performance than if you skip it and end up developing a skin cancer.Train hard, train healthy.
Long time triathlete with multiple IM finishes and over 30 HIM since 2001. 70.3 WC x4, Kona x 1.
Previous medical contributor to Triathlete Magazine and Inside Triathlon now the author and producer of the TriDoc podcast on iTunes, Google Play and Stitcher