Skin cancer is the most common form of cancer. Identifying the early signs of the dreaded disease could be a life-saving discovery for your patients.
Jan Rogers, PhD, and
Sandra J. Maurizio, RDH, MSEd
Cancer of the skin is the most common type of cancer. Dental hygienists and other health-care providers are in a unique position to recognize abnormal skin lesions on their patients. Dental hygienists are well aware of their role in the detection of oral cancer, but the extraoral examination should include a thorough examination of the skin and palpation of the lymph nodes. The role of the dental hygienist includes total patient care; therefore, the skin in the head and neck region, along with any other exposed skin, should be examined.
Malignant melanoma is a particularly dangerous type of skin cancer. It accounts for only 4 percent of skin cancers, but results in 79 percent of skin cancer deaths. The American Cancer Society estimates that 44,200 new cases of melanoma will be diagnosed in the United States this year, and approximately 7,300 people will die from the disease.
Malignant melanomas usually develop from pigmented moles and become dark, rapidly spreading lesions. Since early detection can result in 5-year survival rates of over 90 percent, moles should be checked regularly for warning signs of melanoma. In the early stages, melanoma is usually curable. However, it is much more likely to metastasize to other areas of the body than other types of skin cancer. If melanoma is suspected, immediate referral to a physician is essential. Research has resulted in advancements in the treatment of melanoma, and clinical trials are underway to produce more effective treatments.
Risk Factors/Etiology
Although genetics may play a role in the etiology of melanoma, there is a strong relationship between exposure to ultraviolet (UV) light and the development of cutaneous melanoma. Characteristics associated with an increased risk of developing melanoma include individuals with fair skin that burns easily and does not tan well, the presence of a large number of moles, and the tendency to develop freckles. Intermittent, intense UV exposure (particularly blistering sunburns) are more strongly associated with melanoma than lower-level, chronic exposure. About half of all melanomas occur in people over the age of 50, yet it is one of the most common cancers in people under 30. Family history of melanoma can increase the risk up to eight times. Immune suppression medications also can increase the risk of melanoma.
Melanoma begins in the melanocytes, the cells that produce pigment in the skin. Scientists are studying melanoma to determine why some moles become malignant, as well as the role UV exposure and genetics play in the development of the disease. DNA changes may be inherited in a person`s genes or caused by damage from sunlight and other UV sources, such as tanning beds.
Prevention
The easiest and most effective way to prevent melanoma is to protect the skin from sunlight and other ultraviolet light. A sunscreen with a SPF factor of at least 15 should be used whenever skin is exposed to the sun.
Identification
A thorough patient examination includes a careful visual examination of the skin and palpation of the lymph nodes. Lymph nodes that should be palpated include the preauricular, postauricular, occipital, submental, submaxillary, supraclavicular, and the superficial, deep and posterior cervical nodes. Any lymphadenopathy (swelling or enlargement of the lymph nodes) should be evaluated and recorded.
Hard, immobile lymph nodes that are not tender are of particular concern, and the patient should be referred to a physician. A detailed description of skin lesions should be indicated on the patient`s chart so comparisons can be made during recall appointments. The location, color, size, appearance, attachment, texture, consistency, and history of all lesions, including moles, should be recorded. Unusual skin lesions on any exposed areas of the body should be brought to the patient`s attention. A variety of skin lesions can mimic melanoma; therefore, referral to a dermatologist for diagnosis and possible biopsy is essential. The table above identifies specific warning signs that may indicate melanoma.
Types of melanoma
Four types of melanoma include superficial spreading melanoma, nodular melanoma, lentigo maligna, and acral lentiginous melanoma.
Superficial spreading melanoma in situ is the most common form, usually occurring between the ages of 20 to 40, although it can occur at any age. It may affect non-exposed skin, especially the back in men and lower legs in women. In the early phases, the lesion appears flat, multicolored, with irregular or notched borders. The precursor lesion undergoes minor changes over a period of several years before the rate of change accelerates.
Nodular melanoma occurs on normal skin and appears as a nodule with vertical growth predominating over radial growth. The tumor is raised, blue/black, or red, and may be ulcerated.
Lentigo maligna (Hutchinson`s freckle) occurs on the face of elderly individuals as a patch of uneven pigmentation. The lesions are relatively large (3-4 cm diameter), flat, with irregular borders. This is the slowest growing form of melanoma and the least malignant. The lesion slowly extends peripherally and, after many years, a melanoma may develop.
Acral lentiginous melanoma appears as an area of pigmentation on the hairless skin such as palms, soles of feet, and under nail beds. It is the most common type of melanoma in dark-skinned individuals such as African, Asian, and Hispanic populations. Lesions are flat with irregular borders and are particularly dangerous because invasive malignant melanoma quickly develops.
Changes in size, shape, and color of moles should be checked by a doctor promptly. Moles can be present at birth or appear during childhood or young adulthood. Moles that appear later in life should be evaluated. Moles that are present at birth are believed to be at greater risk of developing into a melanoma, so they should be carefully watched.
Individuals should do monthly self-evaluations of their skin, noting any changes that develop in moles. It is important to check areas that may be difficult to see such as the back of the thighs or the soles of the feet. The American Cancer Society recommends a cancer-related checkup, including skin examination, every three years for individuals between 20 and 40, and every year for those 40 and older.
Diagnostic Staging
Malignant melanoma is diagnosed according to a staging process. The thickness of the lesion is measured by a pathologist to determine the patient`s prognosis and treatment protocol. This technique is called the Breslow measurement. The thinner the melanoma, the better the prognosis. Generally, melanomas less than 1 millimeter in depth have a very small chance of spreading.
A second system used to determine the appropriate stage is to evaluate the layers of skin that are invaded by the melanoma. The Clark level system uses a scale of I to V to indicate the severity of the melanoma. Level I involves only the epidermis, level II has spread to the dermis, level III involves most of the upper dermis, level IV has spread to the lower dermis, and level V indicates the melanoma has spread to the subcutis. The higher the level, the greater the chance that metastasis has occurred.
A third method of staging melanoma combines both previously described methods. The TNM system is frequently utilized. The "T" stands for tumor and indicates its size and how far it has spread to tissues and skin, "N" indicates the melanoma has spread to lymph nodes, and "M" indicates metastasis to distant organs has occurred.
The survival rate varies according to the stage. The 5-year relative survival rate is 90 percent for stages 0 and I, 80 percent for stage II, 50 percent for stage III, and 20-30 percent for stage IV.
Due to advancements in treatment and diagnosis, recently diagnosed patients have more favorable survival rates.
Treatment
Treatment of melanoma is individualized and may include excision, lymph node biopsy and/or removal, surgery for metastatic melanoma, chemotherapy, radiation therapy, immunotherapy, cytokine therapy, and vaccine therapy. In addition, ongoing clinical trials are investigating new therapies. Gene therapy and DNA research are providing additional insights into the diagnosis and treatment of melanoma.
Conclusion
Skin cancers are rapidly increasing in the United States. Early detection is critical to prevent unnecessary deaths. Melanoma is the most deadly skin cancer, but is curable with early detection. Dental hygienists and other health-care providers play a vital role in the identification of suspicious lesions on their patients. The patient may not be aware of the lesions and may need to be encouraged to seek medical attention. Knowledge of the warning signs and how to identify melanoma is essential to aid dental hygienists in detecting suspicious lesions. A simple suggestion to the patient to have a mole evaluated by a physician could identify malignant lesions in the early, treatable stages and save a life.
Jan Rogers, PhD, is an associate professor in the department of health-care professions at Southern Illinois University-Carbondale. Sandra J. Maurizio, RDH, MSEd, is an assistant professor and program director in the dental hygiene program at SIU-Carbondale.
References
- Darby ML, Walsh MM. Dental hygiene theory and practice. Philadelphia: W.B. Saunders; 1995:303-325.
- Fehrenbach MJ, Herring SW. Illustrated anatomy of the head and neck. Philadelphia: W.B. Saunders; 1996:248-261.
- Mehregan AH, Hashimoto K. Pinkus` Guide to Dermatohistopathology. 5th ed. Norwalk, CT: Appleton & Lange; 1991:449-468.
- The Skin Cancer - Melanoma Resource Center. [Online], American Cancer Society. Available: http://www.cancer.org/
- Sommers MS, Johnson SA. Davis`s Manual of Nursing Therapeutics for Diseases and Disorders. Philadelphia: F.A. Davis; 1997:665-669.
- Thibodeau GA, Patton KT. The Human Body in Health and Disease. St. Louis, Mo: Mosby; 1997:105-124.
- Walter JB. An Introduction to the Principles of Disease. 3rd ed. Philadelphia: W.B. Saunders; 1992:588-593.
- Whited JD, Grichnik JM. Does this patient have a mole or a melanoma? JAMA. 1998; 279:696-701.
- Wilkins EM. Clinical practice of the dental hygienist. 7th ed. Baltimore: Williams & Wilkins; 1994:116-127.
The incidence of malignant melanoma has increased dramatically, from a 1-in-1,500 risk of developing melanoma in the 1930s to a 1-in-75 risk of developing melanoma in the year 2000.
Warning signs of malignant melanoma:
The ABCD Rule
Asymmetry - Benign moles are symmetrical; each half is a mirror image of the other. Melanoma lesions are asymmetrical.
Border - Benign moles are outlined by a distinct border, but melanoma lesions exhibit irregular or indistinct, sometimes notched, borders.
Color - Benign moles may be any shade of brown and are usually evenly colored. Melanomas tend to be unevenly colored, exhibiting a mixture of colors and shades (brown, black, white, red, and/or gray).
Diameter - Melanoma lesions are often larger than 6 mm (1/4 inch), about the diameter of a pencil eraser.
Diagnostic stages associated with melanoma
Stage 0 - The melanoma is in situ, meaning it is in the epidermis only. This stage corresponds to Clark level I.
Stage I - The melanoma is a low-risk tumor, less than 1.5 millimeters using the Breslow measurement, or level II or III in the Clark system. It is localized in the skin and has not spread to lymph nodes or distant organs.
Stage II - The melanoma is greater than 1.5 millimeters (Breslow measurement) and can be Clark level IV or V. It appears to be localized to the skin and has not been found in lymph nodes or distant organs.
Stage III - The melanoma has spread to lymph nodes near the affected skin.
Stage IV - The melanoma has spread beyond the skin and lymph nodes near the affected area to other organs, such as the lung, liver, or brain, or to distant areas of the skin or lymph nodes.
Should you have fun in the sun or run from the sun?
The intensity of the sun`s rays are related to several factors, including closeness to the equator, altitude, season of the year, time of day, cloud cover, and the ozone "hole." Ultraviolet rays are most intense when the sun is high in the sky, during the midday which is usually between the hours of 10 a.m. and 4 p.m. If you are not sure about the sun`s intensity, take the shadow test: If your shadow is shorter than you, the sun`s rays are the strongest.
UV radiation also can pass through water, so don`t assume you`re safe from UV radiation if you`re in the water and feeling cool. Also, be especially careful on the beach and in the snow because sand and snow reflect sunlight and increase the amount of UV radiation you receive.
If you plan to be outdoors, you may want to check the UV Index for your area. The UV Index usually can be found in the local newspaper, or on TV and radio news broadcasts. It also may be available through your local phone company, and is available on the Internet at the National Weather Service Climate Prediction Center`s home page (www.nnic.noaa. gov/cpc/).
--- American Cancer Society
Additional information
The National Cancer Institute`s
Cancer Information Service
1-800-4-CANCER
www.cancertrials.nci.nih.gov
The American Cancer Society
www.cancer.org
