Skin Cancer: Cutaneous Melanoma
D. Russell Johnson, MD, Whidbey Dermatology
Cutaneous melanoma is a skin cancer derived from the pigment making cells of the skin. Melanomas often appear as brown or black, irregularly shaped growths. They may arise anywhere on the body, including areas that do not receive regular sun exposure. Consequently, an individual who has one or more sunburn(s) as a child is at increased risk for developing melanoma as an adult. Additional risk factors include having a fair complexion, blonde or red hair, greater than 20 moles, moles with irregular shape, or a family history of melanoma.1
Explosion of Melanomas
The explosion of melanomas in Island County over the last eight years mirrors a larger national trend. Twenty-five melanomas were diagnosed in Island County in 1998 compared to 13 in 1992.2 It is now estimated that one out of every hundred people in the United States will be diagnosed with melanoma in their lifetime.3 Mortality from melanoma has increased 17% nationally since 1970. Island County’s mortality rate of 2.9 per 100,000 is comparable to the current state and national rates.4
Prognosis of Melanoma
Extensive studies of patients with melanoma indicate that the prognosis depends on the depth of the primary tumor, involvement of lymph nodes, and presence of remote metastases. The relationship between tumor thickness and long-term survival is striking. Patients with tumors less than 0.75 millimeters in depth (measured from the top of the skin to the maximum depth of invasion) have a life expectancy similar to disease-free individuals. For melanomas over 1 millimeter (thickness of a dime), morbidity increases in proportion to tumor thickness.
Improved Surveillance
Due to improved surveillance and earlier detection of melanomas in recent years, more "thin" melanomas are being diagnosed.1 Treatment of melanomas less than 0.75 millimeters in depth consists only of wide surgical excision. Because these tumors almost never spread to remote sites, further medical evaluation and cancer staging is not generally regarded as necessary. For these reasons, most melanomas are treated on an outpatient basis and most patients with newly diagnosed melanoma do not undergo conventional staging.
Education & Awareness
Whidbey General Hospital’s efforts to impact on deaths from melanoma in Island County are directed towards education intended to raise awareness about melanoma risk factors (The Pulse, Vol 7. No.2, Spring/Summer 2000) and events intended to raise awareness about melanoma. The Whidbey General Hospital Health Fair offers annual skin cancer screening that has resulted in early identification of both melanoma and non-melanoma skin cancers in the past.
References
1. Berwick M. Epidemiology, Current trends, risk factors, and environmental concerns. In Balch CM, Houghton AN, Sober AJ, Soong S, eds. Cutaneous Melanoma. St. Louis, Missouri: Quality Medical Publishing, Inc., 1998, p. 551-571.
2. Washington State Cancer Registry, State of Washington, Department of Health.
3. Langley RGB, Branhill RL, Mihm MC Jr, Fitzpatrick TB, Sober AJ. Neoplasms: Cutaneous melanoma. In Freedberg IM, Eisen AZ, Wolff K, Austen KF, Goldsmith LA, Katz SI, Fitzpatrick TB, eds. Fitzpatrick’s Dermatology in General Medicine, 5th ed. The McGraw-Hill Companies, Inc., 1999, p. 1080.
4. 1998 Cancer in Washington, Annual Report of the Washington State Cancer Registry, Melanoma of the Skin, p. 87.