Mitotic rate is the measure of tumor proliferation, expressed in millimeters squared. The Clark level refers to the area of invasion within the skin and correlates with Breslow depth, which measures the depth of invasion in millimeters.
Clark level 1 involves only intraepidermal invasion of the epidermis, level 2 shows tumor in the papillary dermis, level 3 shows the tumor filling the papillary dermis, level 4 shows the tumor in the reticular dermis, and level 5 shows the tumor entering the fat of the subcutaneous tissue.
As with many malignancies, early diagnosis directly corresponds with chances of survival. The staging of melanoma is as follows: localized disease (stages I-II), regional disease (stage III), and distant metastasis (stage IV). In stage I, the three most important factors for predicting outcome are Breslow depth, mitotic factor, and ulceration.
For patients with localized metastasis (stage III), the sentinel lymph node biopsy is the key prognostic factor. For patients with distant metastasis, the location of the metastasis is the most important prognostic factor. The presence of ulceration or regression overall usually indicates a poor prognosis.
Patient self-examination and education
Patients should be instructed to examine their own skin on a monthly basis, enlisting the help of a partner or loved one if possible.
Inform the patient that the skin examination should be performed while the patient is fully nude and in a well-lit area. A second mirror can help the person assess hard-to-see areas such as the back, underarms, back of legs, genitalia, buttocks, and bottom of the feet.
Remind patients that skin cancers can develop anywhere, not just on areas where the sun shines, so they need to check every inch of their skin.
Providing information on safe sun exposure goes hand-in-hand with instructing patients on how to perform a skin self-examination. Encourage patients to enjoy their lives, be healthy, and get outdoor exercise, but to do so in a way that does not increase their skin cancer risk.
Patients—and providers, for that matter—should use sunscreen with a skin protection factor (SPF) of 30 or higher. The sunscreen should be applied liberally and reapplied at least every two hours. Nevertheless, patients should seek shade whenever possible. Remind them that they are still exposed to UV radiation even when they are in a shaded area or when the weather is slightly overcast.
Special attention needs to be devoted to protecting one’s skin with sunscreen as well as with hats and other sun-protective clothing when the person is near water, sand, or snow, as all these elements reflect light back up onto the person. Tell patients that if they are able to read a book outside, then ultraviolet light is touching them.
Let patients know that vitamin D may be more safely obtained by means of a healthy diet and, if the clinician deems necessary, supplementation, rather than from sunlight exposure. Be sure they also understand that the concept of slowly getting more sun (or tanning-bed use) to gear up for a vacation in the sun is no more than a dangerous myth, as is the idea that it’s acceptable to get a tan as long as one does so only for special occasions.
Melanoma is the deadliest skin cancer, but early diagnosis yields the best chance for long-term survival. It is incumbent upon the medical community to know the risk factors for this disease, to screen all patients on a routine basis, to teach patients how to perform skin self-examinations and to be cognizant of the warning signs of melanoma.
Primary-care clinicians who do not feel comfortable conducting skin examinations should recommend that the patient make an appointment with a dermatology provider for such a check.
Abby A. Jacobson, PA-C, is a physician assistant practicing in dermatology at Delaware Valley Dermatology Group in Wilmington, Del.
- Swetter SM. Cutaneous melanoma. Medscape. 2012 Oct 8. Available at emedicine.medscape.com/article/1100753-overview#a0199.
- Daniel CG, Thompson JA, Andtbacka R et al. Melanoma, Version 2.2014. National Cancer Care Network Clinical Practice Guidelines in Oncology. Available at NCCN.org.
- Cockburn M, Swetter SM, Peng D et al. Melanoma underreporting: why does it happen, how big is the problem, and how do we fix it? J Am Acad Dermatol. 2008;59(6):1081-1085.
- Miller AJ, Mihm MC Jr. Melanoma. N Engl J Med. 2006;355:51-65.
- Elwood JM, Jopson J. Melanoma and sun exposure: an overview of published studies. Int J Cancer. 1997;73(2):198-203. Available at onlinelibrary.wiley.com/doi/10.1002.
- Elwood JM, Gallagher RP, Hill GB et al. Pigmentation and skin reaction to sun as risk factors for cutaneous melanoma: Western Canada Melanoma Study. Br Med J (Clin Res Ed). 1984;288(6411):99-102. Available at www.bmj.com/content/288/6411/99.pdf%2Bhtml.
- Cust AE, Armstrong BK, Goumas C, et al. Sunbed use during adolescence and early adulthood is associated with increased risk of early-onset melanoma. Int J Cancer. 2011;128(10):2425-2435. Available at onlinelibrary.wiley.com/doi/10.1002/ijc.25576/pdf.
All electronic documents accessed April 17, 2014.