Melanoma: Causes, Risk Factors, Signs, Symptoms, Investigations, Stages, Treatment, Prevention
Melanoma is one of a serious type of skin cancer. It starts in the melanocytes, which are the cells that produce melanin. Melanin is the pigment which is responsible for giving the skin its color. Melanoma can occur in the eyes and can also develop in the internal organs like intestines; however, this happens rarely.
The exact cause behind all melanomas is not known; however, exposure to ultraviolet (UV) rays or tanning beds and lamps puts you at a great risk for developing melanoma. Treatment includes surgery, chemotherapy, radiation therapy, biological therapy and targeted therapy.
Causes of Melanoma
The exact cause is not clear, but scientists believe that when something goes wrong with the melanocytes, which are the cells which produce melanin giving the skin its color, it results in cancer. Normal skin cells always develop in an orderly and controlled manner and the older cells are pushed towards the skin's surface when new cells are formed. The old cells die and are gradually shed off. In melanoma, there is some impairment in the DNA of the cells which leads to uncontrollable growth and division of new cells resulting in formation of a mass or tumor of cancerous cells.
The Factors Which Are Thought To Cause This Damage In DNA Of The Skin Cells Include:
- Exposure to UV (ultraviolet) rays from the sun.
- Exposure to UV (ultraviolet) rays from tanning beds and lamps.
- Genetic factors.
- Environmental factors.
Risk Factors for Melanoma
- Individuals with fair skin have less melanin in their skin, which means that they get less protection from the UV rays. So, people with light-colored eyes, blond or red hair, and who get freckles or get sunburn easily are at an increased risk to develop melanoma when compared to people with darker complexions.
- Individuals with excessive exposure to UV radiation are at an increased risk for developing skin cancer, including melanoma.
- Having a previous history of sunburn increases the risk of melanoma.
- Individuals who live near the equator or at higher elevation are at an increased risk for developing melanoma.
- Individuals who have lot of moles (greater than 50) are at an increased risk of having melanoma. If the mole is not like an ordinary mole and is unusual in appearance, such as dysplastic nevi, which are bigger than normal moles with a combination of colors and irregular borders, are more prone to having melanoma.
- Individuals who have weak immune systems are at an increased risk for developing skin cancer.
- Having a family history of melanoma increases the risk for developing one.
Signs and Symptoms of Melanoma
Melanomas commonly develop in those regions of the body which are more exposed to the sun, such as face, arms, back and legs. However, melanomas can occur anywhere in the body. Individuals with darker complexion may have hidden melanomas in the palms, soles of their feet and fingernail beds. Melanomas need not always appear as a mole. It may also occur in a normal looking skin.
The Signs and Symptoms Indicating Melanoma Are:
- Changes in an old, existing mole.
- The formation of new pigments, moles or any atypical growth on the skin.
Normal Moles: Normal moles usually have a consistent color like black, brown or tan and have a well defined border. Normal moles are round or oval in shape and are generally smaller than 6 mm (around 1/4 inch) in diameter.
Moles Which May Indicate Melanoma
Identifying the characteristics of cancerous or unusual moles is very important. For this, always remember the letters A-B-C-D-E, which mean:
- A Stands for Asymmetrical Shape, i.e. moles having irregular shapes, like two different halves, should not be ignored.
- B Stands for Irregular Border, i.e. moles with irregular, scalloped or notched borders is indicative of melanoma.
- C Stands For Changes In Color: Any skin growths with uneven distribution of color or having different colors should not be ignored.
- D Stands for Diameter, i.e. any new skin growth or a mole having a diameter of more than 6 mm (1/4 inch) should not be ignored.
- E Stands for Evolving: Look for any type of changes over the time, like if the mole has grown in size or if there are any changes in its shape or color. There also may be new signs and symptoms in the moles such as bleeding or itchiness.
Other Changes To Watch Out For In A Mole Are:
- Presence of scales on the moles.
- The pigment may spread beyond the mole into the skin around it.
- Any bleeding or oozing.
These are the melanomas which develop in those areas of the body which have had little or no sun exposure, e.g. scalp, palms, between the toes, soles of the feet or genitals. Individuals with darker skin are more prone to having hidden melanomas.
Some Examples Of Hidden Melanomas Are:
- Subungual melanoma occurs beneath a nail and is very rare. People with darker skin or blacks are more vulnerable to it. A subungual melanoma often has black or brown discoloration and is usually mistaken for a bruise.
- Mucosal melanoma is a melanoma which develops in the mucous membrane lining the mouth, nose, esophagus, urinary tract, anus and vagina.
- Ocular melanoma or eye melanoma develops in the uvea, which is the layer present under the sclera. Eye melanoma can cause changes in the vision and for this reason can be detected during an eye exam.
Investigations for Melanoma
You can conduct a self-exam from time to time so you are familiar with the freckles, moles and other marks on your skin which are normal and any changes in them as time goes on. You can do this by standing in front of a full-length mirror and using a hand-held mirror at the same time for examining the areas which are hard to see. Make sure to check all the sides of your arms and legs (front, sides, back), your scalp, fingernails, soles of the feet, groin region and the skin between the toes.
- Punch biopsy where a round piece of skin surrounding a suspicious growth or mole is removed.
- Excisional biopsy where the entire growth or mole is removed with a small margin of the normal skin.
- Incisional biopsy where only the irregular part of a growth or mole is removed for testing.
Stages of Melanoma and Determining its Stages
Stage I melanoma is quite small and usually can be treated successfully. The higher the staging, the lower the chances are of successful treatment and complete recovery. In stage IV, the cancer metastasizes beyond the skin to other regions or organs of the body, such as liver or lungs.
The Stages Of Melanoma Are Determined By:
- Thickness: A melanoma's thickness is determined by examining it under a microscope and measuring it with a micrometer. The greater the thickness of a melanoma, the more advanced is the cancer.
- Extent of the melanoma: Sentinel node biopsy is done to determine if the melanoma has metastasized to the adjacent lymph nodes.
Treatment for Melanoma
Surgery is done for removing early-stage melanomas where the melanoma is removed along with a margin of normal appearing skin and a layer of underlying tissue. If the melanoma is very thin, then it may be removed completely during the biopsy and does not require further treatment
- Surgery is done to remove the lymph nodes which have been affected by the melanoma.
- Chemotherapy uses drugs or chemical to kill cancer cells. It can be given in a pill form or intravenously or both.
- Radiation therapy involves the use of high-powered energy beams (e.g. x-rays) which are directed at specific points of the body to destroy cancer cells. It can also be used to alleviate symptoms of melanoma. A common side effect of radiation therapy is fatigue; however your energy levels often return after the treatment is complete.
- Biological therapy helps by boosting the immune system thereby helping the body fight cancer. Biological treatment includes interleukin-2 and interferon. Side effects resemble flu symptoms, such as fever, chills, headache, fatigue and muscle pain. Ipilimumab (Yervoy) is commonly used for treating advanced melanoma which has metastasized from its original location.
- Targeted therapy involves using medications which target specific abnormalities of the cancer cells. Vemurafenib (Zelboraf) is used to treat advanced melanoma which doesn't respond to surgery.
Prevention of Melanoma
- Always try to avoid the sun when the sun rays are at their harshest (generally between 10:00 a.m. to 4:00 p.m.)
- Always wear broad-spectrum sunscreen with a minimum SPF of 15, all through the year, on all the exposed areas, even the lips, tips of ears, and the back of the neck and hands. Reapply the sunscreen every 2 hours if you are outside or are perspiring.
- Always wear protective clothing which cover your face, arms, legs, such as broad-brimmed hat, sunglasses etc.
- Avoid tanning booths/beds, as they release UV radiation, which increases the risk for developing skin cancer.
- Examine yourself, your skin, from time to time so you become familiar with it and are able to notice any skin changes which may occur. You can do this by standing in front of a full-length mirror and at the same time using a hand-held mirror for examining the regions which are hard to see. Make sure to check all the sides of your arms and legs (front, sides, back), your scalp, fingernails, soles of the feet, groin region and skin between the toes.