|
Course Sample:
Epidemiology: Who gets Melanoma and Why? 53,600 new cases of melanoma are predicted to occur in the United States in 2002, with deaths from the disease estimated at 7,400.1 Over the last three decades the incidence of melanoma has continued to increase, although the rate of increase has begun to level off in the 1990's. Malignant melanoma occurs more frequently in males than females. Females tend to develop melanomas of the extremities, while men tend to have more melanomas of the trunk and head and neck. The incidence rises steadily after age 20 with a median age at diagnosis in the mid fifties. Melanoma affects patients of all ages. It is not uncommon in those in their twenties and thirties. However, seventy-five per cent occur in those over seventy years of age. While melanoma occurs most frequently in Caucasians, it does occur in blacks, most frequently arising on the soles of the feet or palms of the hands. Asians and Hispanics are at very low risk for this tumor compared to Caucasians. Melanoma is more common in the southwestern continental United States, Hawaii, Israel, and Australia, all sunny climates located close to the equator, where the ultraviolet radiation from the sun is most intense. The most significant risk for melanoma is exposure to ultraviolet light. Prolonged exposure and/or sunburn occurring in childhood and adolescence increase the risk. The phenotype most frequently associated with malignant melanoma has fair skin and light-colored hair, easily becomes sunburned and rarely develops a suntan. Those who 'worship the sun', including using tanning beds that emit wave lengths of ultraviolet light similar to the sun, increase their risk of developing malignant melanoma. However, the role of tanning beds that produce lower wave length ultraviolet radiation than the sun have not definitively been shown to increase the risk of melanoma in regular users. The wave length emitted by the tanning bed often is not prominently displayed on the unit. Nonetheless, their use should be limited especially among those with the 'melanoma phenotype'.7 The role of sunscreens in melanoma prevention is discussed later. Overall, the lifetime cumulative risk of malignant melanoma in Americans is about one percent. Those who have had one malignant melanoma have in increased risk ranging from four to thirty percent of developing subsequent primary melanomas. Other risk factors for malignant melanoma include: family history of melanoma, moderate freckling, dysplastic nevi (atypical moles), several large non-dysplastic nevi, multilple small nevi, and familial dysplastic nevus syndrome. These conditions increase melanoma risk two to five fold. A mutation of the p16 tumor suppressor gene has been observed in both familial and sporadic melanomas. Further understanding of the genetic basis of melanoma will provide better identification of those at risk and will allow targeted screening and prevention efforts.8 Nurses should be alert to the 'melanoma phenotype', and the other known risk factors and counsel these patients about avoiding sun exposure. Parents also need to be educated about the increased risk generated by childhood and adolescent sunburns. Asking patients about their hobbies and recreational activities (golf, swimming, boating, fishing, sun worshipping) will identify those with the potential to have significant sun exposure. In the spring, when many flee the northern parts of the U.S, and head south toward the equator, cautions about sunburning should be reinforced along with specific interventions to minimize ultraviolet light exposure. Can you Prevent Melanoma? The most effective preventative measure that can be taken to avoid melanoma is minimizing sun exposure. Table I outlines ways to limit exposure to the sun's ultraviolet light.
Table I MINIMIZING EXPOSURE TO ULTRAVIOLET SUNLIGHT2 - Change patterns of outdoor activities to reduce exposure to high intensity ultraviolet light: avoid a UV Index of > 4*
- Wear protective clothing when exposed to sun: long sleeves, long pants, hat with a brim, socks
- Use sufficient quantities of adequately protective sunscreen on exposed skin: Sun Protective Factor (SPF) >14** that blocks both UVA and UVB radiation.
|
*The Ultraviolet (UV) Index predicts the amount of ultraviolet sun exposure based on geography and other climatic conditions. The National Weather Service (NWS ) issues the geographically specific UV Index daily, on a scale of 1-10; an index of 5 or above indicates moderate to very high intensity UV light. The Index is readily available from the NWS and on the Internet. **Whether using higher SPF sunscreens confers an advantage is unknown. The data regarding the value of sunscreens in preventing melanoma is controversial. No prospective randomized controlled trials of sunscreen use on the prevention of melanoma are currently available. Whether sunscreens not only protect against sunburn (a known risk factor for melanoma), but also filter out UV light is unclear. In Australia 74% of the population now regularly uses sunscreen; the incidence and mortality from melanoma is decreasing. Likewise, the rates are also falling among Caucasian Hawaiians who have the highest per capita use of sunscreen in the U. S.8 Retrospective studies correlating the inverse incidence of melanoma with annual spending for sunscreen show a protective effect. Thus, current recommendations include the use of sunscreen until more definitive data is available. To be effective, sunscreen needs to be used properly: apply once every two hours using one ounce to cover the entire exposed body; reapply after swimming.10 Remember that using sunscreen in NOT a substitute for avoiding UV exposure. Chemoprevention, the administration of pharmaceuticals, vitamins or minerals in an effort to prevent cancer, remains under investigation in melanoma. Using dysplastic nevi as a surrogate end point for melanoma, studies are evaluating the effects of retinoids in reversing dysplastic changes. Aspirin, nonsteroidal anti-inflammatory drugs, COX-2 inhibitors, beta carotene and other carotene agents, and selenium are of interest as potential chemopreventation agents and are likely to be studied in clinical trials. Currently, there is no known effective chemopreventative agent for melanoma. Nurses need to teach patients the ways to avoid undue sun exposure and how to properly use sun screens. Patients also need to be cautioned against self-prescibing dietary supplements such as vitamin A, beta carotene and selenium, until their ability to prevent melanoma is defined. These agents can be dangerous and extremely toxic if not used in appropriate doses. Patients interested in chemoprevention should be referred to the National Institutes of Health (www.nih.gov) web site to explore clinical trials in which they may be able to participate. Screening & Early Detection: Does it Work? Because the majority (but not all) melanomas arise on the surface of the skin, early detection theoretically can be easily achieved. Early stage melanomas are highly curable, while those diagnosed in later stages are highly lethal. Thus, early detection has the potential to markedly decrease mortality from this disease. Skin self-examination done in a consistent fashion on a regular schedule can detect skin changes that herald malignant transformation, not only to melanoma, but also to other less lethal skin cancers (basal cell carcinoma, squamous cell carcinoma). How to Perform a Skin Self-Exam Performing an adequate skin self-exam requires a hand-held mirror and blow dryer, and a full length mirror. The exam must be performed under adequate lighting. Patients should begin by examining the palms of their hands and forearms. Next, turn the arms over and examine the back of the hands paying attention to the nail beds and the webbing between the fingers; examine the anterior forearm by flexing the elbows and viewing them in the full length mirror. Drop the arms to the sides and view the entire anterior body in the mirror. Develop a systematic approach to viewing the body, for example, view the body in a clockwise fashion starting with the right shoulder, upper arms and anterior chest, proceeding to the right side of the abdomen, and then the right anterior leg, followed by the left anterior leg, left abdomen, and finally left anterior chest and shoulder. No particular order is essential, but the same systematic approach should be used at each exam to maximize familiarity with the skin, its pigmentation variations, moles, nevi, etc. The sides of the body are then examined in the full-length mirror. With the back to the full length mirror examine the backs of the legs and buttocks; view them looking back over each shoulder. Use the hand-held mirror to view the upper back, shoulders and posterior neck as reflected in the long mirror. Next, take a seat and examine the anterior feet, paying attention to the nail beds and the webbing between toes. View the soles of the feet; in those with limited mobility, this may best be accomplished by using the hand held mirror. Use the mirror to examine the inner surface of each leg while seated with the legs extended. While standing or seated on the edge of a stool, use the hand mirror to examine the genitals, exposing the labia minora in women, and the entire surface of the scrotum in men. Examine the anal area using the hand mirror. Complete the exam using the blow dryer to expose the scalp while viewing it in the mirror. A spouse or friend may be enlisted to assist with the exams, but it should be the same person each time to maximize the detection of changes. ANY change in the skin should be evaluated a physician. Illustrated patient self examination instructions are available on the American Academy of Dermatology's web site and from the American Cancer Society.2 The American Cancer Society recommends monthly skin self-examination. Who should have a Total Skin Exam by a Health Care Professional and How Often? The American Cancer Society recommends a complete skin exam every three years for those ages twenty to thirty-nine, and then yearly as part of an annual physical. Annual examinations are recommended by the American Academy of Dermatology, the Skin Cancer Foundation, and an NIH Consensus Conference on Early Melanoma for all individuals with familial dysplastic nevus syndrome.15 Others at high risk (melanoma phenotype, dysplastic nevi, many small nevi, several large nondysplastic nevi, moderate freckling, family history of melanoma) should discuss their risk with their physician and determine a frequency for a professional skin examination based on their individual risks. To detect recurrent or second primaries, patients with a treated melanoma should be professionally examined as frequently as every three months for four to five years after diagnosis dependent on the stage.3 Whether periodic screening reduces mortality is unknown and will probably remain so due to the difficulty in performing prospective randomized clinical trials. However, observational studies of educational campaigns, and case-control studies suggest both a decrease in incidence as well as in mortality. Because skin examination is cheap compared to screening methods for other diseases, common sense dictates continuing melanoma screening by both self-examination and periodic professional exams especially in targeted high-risk groups. Teaching skin self-examination, identifying high risk individuals, and developing systems to track professional screening interval compliance fall into the purview of nurses in all settings, but most frequently to those working in primary care, dermatology, and oncology. Advanced practice nurses must hone their skills in visually identifying suspicious lesions. How do you Recognize a Melanoma? |
