Melanoma

Introduction:

Melanoma of the skin (also called"malignant melanoma") has become a very common skin tumor, which develops out of the pigment cells under the influence of the ultraviolet light. It is usually a dark brown, black or purple bluish skin lesion(see below). The frequency among the North American population was 1 in 250 in 1980, but has increased to 1 in 90 in the year 2000. In 1995 there were 32,100 new skin melanoma cases diagnosed in the US. (Ref. 3).Much has been theorized about why this should be, but there is no good explanation for this other than the fact that more people may expose themselves to the sun for longer hours.

Causes:

Why do melanomas develop? Exposure to sunlight, specifically the ultraviolet B rays (UVB), is significantly linked to the risk of melanoma development. Epidemiological data has shown this: people who live close to the equator have melanomas more frequently.

Migration data showed that subpopulations with a low melanoma rate who moved to areas with more sun exposure turned into high rate melanoma subpopulations. Furthermore we know that melanoma is less frequent in more pigmented people, there is an inverse relationship to the degree of skin pigmentation. There are some genes that also play a role in terms of susceptibility. Also, there seems to be an interplay with carcinogens from the environment, which may remove a repressor gene, and there is a weakening of the immune system locally at the area of repeat sun exposure.

Subgroups of melanomas

There are four distinct subgroups of melanomas(Ref. 1, 2 and 3): see table with links above for details (click on "melanoma"below).

Disclaimer:

This outline is only a teaching aid to patients and should stimulate you to ask the right questions when seeing your doctor. However, the responsibility of treatment stays in the hands of your doctor and you.

References:

1. Cancer: Principles &Practice of Oncology, 4th edition, by V.T. De Vita,Jr.,et. al J.B.     LippincottCo.,Philadelphia, 1993.Vol.2: Chapter on Cutaneous melanoma.

2. The Merck Manual, 7th edition, by M. H. Beers et al., Whitehouse Station, N.J., 1999.     Chapter 126, p. 843-845.

3. Cancer: Principles&Practice of Oncology. 5th edition, volume 2. Edited by Vincent T.     DeVita, Jr. et al. Lippincott-Raven Publ., Philadelphia,PA, 1997. Chapter on Cutaneous     melanoma.

4. SA Rosenberg et al. Ann Surg 1998 Sep 228(3): 307-319.

5. SA Rosenberg  Nature 2001 May 17;411(6835):380-384.

6. T Todo et al. Proc Natl Acad Sci U S A 2001 May 15 ( page not available yet).

7. GJ Tsioulias et al. Ann Surg Oncol 2001 Apr;8(3):198-203.

8. Conn's Current Therapy 2004, 56th ed., Copyright © 2004 Elsevier

9. Ferri: Ferri's Clinical Advisor: Instant Diagnosis and Treatment, 2004 ed., Copyright © 2004 Mosby, Inc

More info on melanoma can be found through this link.

Last Modified: Feb. 2, 2012