Melanoma is a cancer that most often starts in the skin. The skin is the body’s largest organ. It protects your body from injury, infection, heat and ultraviolet light from the sun.
The skin helps control your body temperature and gets rid of waste materials through the sweat glands. It also makes vitamin D and stores water and fat.The skin has 2 main layers. The top layer at the surface is called the epidermis. Below the epidermis is the inner layer, called the dermis. The dermis contains nerves, blood vessels, sweat glands, oil (sebaceous) glands and hair follicles.
The epidermis is made up of 3 types of cells:
- Squamous cells are thin flat cells on the surface of the skin
- Basal cells are round cells that lie under the squamous cells. They are continually made deep in the epidermis. Newly made basal cells push the older cells toward the surface of the skin, where they become squamous cells
- Melanocytes are also found deep in the epidermis, in between the basal cells. Melanocytes make melanin, which gives colour to your skin. When skin is exposed to the sun, the melanocytes make more melanin and cause the skin to tan or darken. Sometimes melanocytes cluster together and form moles (also called nevi). Moles are common and are usually not cancerous.
- Squamous cell skin cancer starts in the squamous cells
- Basal cell skin cancer starts in the basal cells
- Melanoma starts in the melanocytes
Melanoma is less common than squamous cell and basal cell skin cancers (sometimes called non-melanoma skin cancers). Melanoma can start in other places in the body where melanocytes are found, such as the eyes, mouth and vagina or under the fingernails. These types of melanoma are rare.
A sign is something that can be observed and recognized by a doctor or healthcare professional (for example, a rash). A symptom is something that only the person experiencing it can feel and know (for example, pain or tiredness). The signs and symptoms of melanoma can also be caused by other health conditions. It is important to have any unusual symptoms checked by a doctor.
Moles are common. On average, people have between 10 and 40 moles on their body. Most moles develop on a person before the age of 40. A normal mole is round or oval, usually flesh-colored, pink, tan or brown and flat or dome-shaped.
Melanoma has a variety of forms and can appear anywhere on the body. About half of all melanomas start with a change in normal-looking skin. This change usually looks like a dark area or an abnormal new mole. Other melanomas develop from an existing mole, freckle, birthmark or colored spot. This change in a mole, freckle, birthmark or colored spot can occur over several months to years.
Melanomas in men are most common on the back. Melanomas in women are most common on the legs
- A new mark or spot on the skin
- A mole or spot that is changing in size, shape, colour or height (elevation or how much it is raised above the skin)
- A mole or spot that looks different from all of the other spots on your skin
- A mole or spot that is asymmetric (one side of the spot does not match the other)
- A mole or spot that doesn’t have a well-defined border (the edges are irregular, ragged, notched or blurred)
- A mole or spot that is not the same colour all over or has changed colour
- It may be shades of brown, black, pink, red, white or blue
- A mole or spot that is more than 6 mm across (about the size of a pencil eraser)
- A sore that does not heal
- Change in sensation of a mole or spot, including itching, tingling, tenderness or pain
- A mole or spot that is crusted or bleeding
- Spread of pigment from the border of a spot to surrounding skin
- New moles that grow around an existing mole
- Redness or a new swelling beyond the border of a spot or mole
- A growth under a fingernail or toenail or a new pigmented line in a nail
Late Signs and Symptoms
Late signs and symptoms occur as the cancer grows larger or spreads to other parts of the body, including other organs. The symptoms of advanced melanoma will depend on which part of the body is affected. The symptoms are different for everyone and may include:
- Enlarged lymph nodes in the neck, under the arm or in the groin
- Breathlessness, cough or chest discomfort
- Swelling and discomfort in the abdomen
- Pain or discomfort in the bones
- Headaches or nausea
- Unexplained weight loss
- Lack of appetite
Treatment for melanoma is given by cancer specialists (oncologists). Some specialize in surgery, some in radiation therapy and others in chemotherapy (drugs). These doctors work with the person with cancer to decide on a treatment plan.
Treatment plans are designed to meet the unique needs of each person with cancer. Treatment decisions for melanoma are based on:
- Surgery is the main treatment for melanoma and usually cures early stage melanoma
- A number of surgical methods are used to treat melanoma:
- Wide excision is the most common method used to remove melanoma
- Amputation may be necessary to treat melanoma on a finger or toe
- Sentinel lymph node biopsy (SLNB) may be used to see if the cancer has spread to lymph nodes and to more accurately stage the melanoma, predict prognosis, improve local regional control and perhaps improve overall survival
- Lymph node dissection may be used to remove lymph nodes with melanoma metastases in them
- Surgery may be used to remove a metastasis in the brain, lung, liver, bowel, subcutaneous tissues or pancreas
- Skin reconstruction may be necessary for some melanomas
- Biological therapy
- Biological therapy may be used as an adjuvant therapy for some high-risk melanomas
- It is also used to treat advanced melanoma
- Radiation therapy
- Radiation therapy may be used to treat advanced melanoma
- It is also used after surgery to treat lymph nodes that contain cancer cells
- Chemotherapy may be used to treat advanced melanoma or a local recurrence
- Targeted therapy
- Targeted therapy may also be used to treat metastatic or recurrent melanoma
- Follow-up after treatment is finished
- It is important to have regular follow-up visits