Melanoma is a form of skin cancer that affects the melanocytes – the cells in the basal layer of the epidermis, that produce melanin (the pigment that colors a person’s skin). Melanoma can also occur in the mouth, nose, anus, and vagina. Rarely, melanoma affects the eyes and internal organs.

Melanoma skin cancer accounts for about 1% of all skin cancer cases in the country and has the highest mortality rate. The number of melanoma skin cancer cases has risen rapidly over the last 30 years. There has been a 3% increase in cases in men and women aged over 50 years. A little less than 10,000 people will be diagnosed with melanoma skin cancer in 2019.

The exact cause of most forms of skin cancer is still unknown. Higher incidence of skin cancer such as melanoma occurs in people who are regularly exposed to sunlight or use sun and tanning lamps that use ultraviolet rays. It is suggested that long exposure to UV rays damages the DNA of cells and the cells undergo mutation. These abnormal cells tend to multiply rapidly, at a rate faster than normal cells. The existing cells are pushed out by the damaged cells, which form lesions or tumors on the skin surface. The mole-like melanomas are commonly colored black or brown; however, they can be skin-colored, red, pink, purple, blue or white.

Sometimes this form of skin cancer originates from normal moles.

There are many tests to detect cancer. Tests can determine if cancer has spread to other parts of the body from where it first appeared. Tests can also help decide the best form of treatment. For melanoma skin cancer, a biopsy is the best method. A portion of the skin with the suspected growth is removed and examined. The examination will report the rate at which the abnormal cells are multiplying and the presence of lymphocytes (immune system cells). An important characteristic of skin cancer is the cells’ dividing rate, called the mitotic rate.

In melanoma skin cancer, the thickness of the tumor helps determine whether the cancer is likely to spread. A thickness of less than 1 mm is denoted as “thin.” The risk of spreading to the nearby lymph nodes or other parts of the body is very low. A thickness of between 1 mm and 4 mm is denoted as “intermediate.” A thickness greater than 4 mm radically increases the risk of recurrence. If the melanoma is beyond 4 mm thick it is very likely that cancer has already spread.

Staging the melanoma skin cancer is important for treatment decisions. One method of staging melanoma is the TNM system. The primary stage is tagged as “T” category; the second stage is tagged as the “N” category, and the third category is tagged as “M” category. An N category melanoma has spread to the nearby lymph nodes, and an M category melanoma has spread to other parts of the body.

Treatment methods are determined depending on the stage and other factors of the melanoma. Wide excision surgery is used to remove all the cancerous matter. This method is mostly used for thin melanomas and is a relatively simple procedure. Lymph node dissection is carried out if the presence of cancer cells is detected in the nearby lymph nodes.

Radiation therapy is used very rarely for skin cancer, although, if surgery is not an option, doctors might advise it. Chemotherapy is used for advanced melanoma, though it has been found to be less effective, than when it is used for other forms of cancer.

Immunotherapy and targeted therapy are now more in use for the treatment of melanoma skin cancer. Immunotherapy uses specific drugs to help the immune system respond better to melanoma cells. Targeted therapy uses substances that address the abnormal parts of melanoma cells. These work better than chemotherapy drugs as they target only the cancerous cells.