Melanoma

BY Chutiya Chitboonthaweesuk, Phornnattha Kongsatitphan, Tanyarat Saelor

EDITED BY Chate Therdkiet

What is Melanoma?

Melanoma is a type of skin cancer that develops within the cells, melanocytes, which is responsible for producing melanin, the pigment that gives the skin its color. Melanoma can also begin in the eyes, nose, throat, but are extremely rare. The common sites for males with light skin color that experience this disease usually are the chest and back while it is legs for women.  People with darkly pigmented skin have a lower risk of melanoma at these common sites. Melanoma is less common than other types of skin cancer. However, it is more dangerous because it is more likely to spread to other parts of the body if not found and treated early. There are different types of skin melanoma. The most common types are:

• Superficial spreading melanoma: Tumors tend to grow outward on the surface of the skin, which can be characterized as a dark spot on the skin that is changing in shape or getting bigger.

• Nodular melanoma: Tumors appear as a distinct, raised bump on the skin that is often dark brown or black, which makes them hard to find early. Nodular melanoma tends to grow down into deeper layers of the skin, which results in these tumors being discovered at a more advanced stage.

• Lentigo maligna melanoma: This type of melanoma tends to occur in older people. It initally appears as an abnormally shaped tan spot in an area which has been exposed a lot to the sun and tends to grow or change slowly over time.

• Acral lentiginous melanoma (acral melanoma): Acral melanoma starts in areas that do not get a lot of sun exposure, such as palms, soles of feet or under nails.

Causes & Symptoms 

The main cause of melanoma is the exposure to ultraviolet radiation from sunlight or tanning lamps and beds. Melanoma is also likely to occur in people with pale skin which burns easily in the sun or people with red or blonde hair, blue or green eyes. People with a large number of freckles or moles or had a lot of sun exposure and have sunburn a lot in the past also have a greater chance of getting Melanoma.

The first melanoma signs and symptoms often are the development of a new pigmented or unusual-looking growth on the skin or a change in an existing mole. These changes may include color, size, shape, elevation or itching and bleeding. Other symptoms include dark areas under nails or on membranes lining the mouth, vagina or anus. 

Risk Factors

There are several risk factors that can contribute to the development of melanoma skin cancer which include: 

• Exposure to Ultraviolet (UV) light: UV light exposure is a major risk for most cases of melanoma. UV rays are the main cause of damage to the DNA inside the skin cells. Hence, skin cancer will develop as the damage affects the genes that control the skin’s cell growth. The main sources of UV rays are from sunlight, tanning beds, and sun lamps. The pattern and timing of the UV exposure might play a role in the development of melanoma, such as when one gets skin cancer on the body parts that have been linked with frequent sunburns. However, a different type of melanoma can also start in those areas that are not constantly exposed to light. 

• Moles: The more moles one has on their skin, the greater the chance of developing melanoma.

• Lighter skin, hair, and eye color: People with lighter skin, red or blonde hair, blue or green eyes are at increased risk.

• Family history of melanoma: One is higher at risk if one or more of their first-degree relatives has had melanoma.

• Personal history of skin cancer: People that have already experienced melanoma or other skin cancer have a higher risk of developing the condition again.

• Weak immune system: People with weakened immune systems will have less ability to help the body fight off cancerous diseases.

• Age and gender: The risk increases as people age but it can also occur in younger people. The risk varies by age and gender, younger women and older men are more likely to experience melanoma. 

• Xeroderma pigmentosum: XP is a rare inherited condition that lowers skin cells’ ability to repair damage to the DNA. Melanoma is more expected to people with XP.

Treatment

The best treatment for melanoma depends on the size and stage of cancer, the overall health, and each personal preference: 

Immunotherapy - drug treatment that helps the immune system to fight cancer. The immune system might not attack cancer because the cancer cells produce proteins that help them hide from the immune system cells. Usually, immunotherapy is often recommended after surgery for melanoma that has spread to the lymph nodes or to other areas of the body.

Targeted therapy - focuses on specific weaknesses present within cancer cells. By targeting these weaknesses, targeted drug treatments can cause cancer cells to die. Cells from  melanoma may be tested to see if targeted therapy is likely to be effective against the cancer. For melanoma, targeted therapy might be recommended if the cancer has spread to lymph nodes or to other areas of the body.

Radiation therapy - uses high-powered energy beams, such as X-rays and protons, to kill cancer cells, and may be directed to the lymph nodes if the melanoma has spread to those locations. It is also a viable option for treating melanomas that cannot be removed completely with surgery. For melanoma that spreads to other areas of the body, radiation therapy can help relieve symptoms.

Chemotherapy - uses drugs to kill cancer cells, It can also be given in a vein in the  arm or leg in a procedure called isolated limb perfusion. During the procedure, the blood in the arm or leg would not be allowed to travel to other areas of the body for a short period of time so that the chemotherapy drugs are able to travel directly to the area around the melanoma and also would not affect other parts of the body. 

Reference:

“Melanoma | Causes, Symptoms and Treatments.” Cancer Council, www.cancer.org.au/cancer-information/types-of-cancer/melanoma.

Melanoma - Diagnosis and Treatment - Mayo Clinic. 22 July 2023, www.mayoclinic.org/diseases-conditions/melanoma/diagnosis-treatment/drc-20374888.

“Melanoma Skin Cancer Risk Factors | Melanoma Risk Factors.” American Cancer Society, www.cancer.org/cancer/types/melanoma-skin-cancer/causes-risks-prevention/risk-factors.html.

“Melanoma - Symptoms and Causes - Mayo Clinic.” Mayo Clinic, 22 July 2023, www.mayoclinic.org/diseases-conditions/melanoma/symptoms-causes/syc-20374884#:~:text=Melanoma%20is%20a%20form%20of,into%20the%20deeper%20skin%20layers.

“What Is Melanoma Skin Cancer? | What Is Melanoma?” American Cancer Society, www.cancer.org/cancer/types/melanoma-skin-cancer/about/what-is-melanoma.html.