Melanoma is a deadly skin cancer. Skin cancers are subdivided into different kinds based on which skin cells they come from. Melanoma originates from pigmented cells (melanocytes) interspersed in the top layers of the skin. In contrast, non-melanoma skin cancers (basal cell carcinoma and squamous cell carcinoma) arise from keratinocytes (non-pigmented cells comprising the bulk of the very top layer of the skin). There is no relationship between melanoma and non-melanoma skin cancers.

Basal cell carcinoma and squamous cell carcinoma rarely metastasize (spread through the body). Melanoma metastasizes if not removed in time. Hence, it is the most dangerous skin cancer.

It appears that some melanomas grow quickly, invade the skin, and spread through the body fast. There are other melanomas which may stay in the top layer of the skin for decades and only then start invading. Yet, even thin melanomas can spread through the body and kill. A test to reliably distinguish between slow-growing melanomas with low immediate capacity for metastases and aggressive “fast killer” melanomas has not yet come to fruition. All melanomas are currently treated with the assumption that they can and will kill the patient unless removed.

If cancer is detected during sentinel node biopsy, the treatment usually becomes more aggressive. Many more lymph nodes are removed. Sentinel node biopsy is generally not recommended for those with thin (under 1 mm in thickness) or thick (over 4 mm in thickness) melanomas. This procedure is controversial. Many dermatologists still believe that doing a sentinel node biopsy does not improve patients’ chances for survival. It appears though, that for most patients with intermediate melanomas this procedure is becoming the standard of care.

If melanoma invades the skin and then migrates to the internal organs or distant sites, the prognosis is very poor (only 6% of patients survive to the 5-year mark). The treatment of advanced melanoma is quite inadequate.

Anyone who has had a melanoma in the past needs a lifetime of follow up with a dermatologist for regular skin exams. The purpose of the exams is not only to detect a possible recurrence of the same melanoma, but also to monitor for the appearance of new melanomas. Monthly self-examinations and sun protection are also recommended.

Alexander Doctoroff, D.O., F.A.O.C.D.
Assistant Chief of Dermatology,
Veterans Administration Medical Center
East Orange, New Jersey

Assistant Clinical Professor of Medicine,
University of Medicine and Dentistry of New Jersey