Written by Ada’s Medical Knowledge Team
What is melanoma?
Melanoma, also called malignant melanoma and cutaneous melanoma, is one of the most aggressive forms of skin cancer. According to the American Cancer Society, over 91,000 new diagnoses of melanoma will be confirmed in the U.S. in 2018. It is much more common for adults to be affected by melanoma than children. The condition is primarily caused by prolonged, frequent or intense exposure to ultraviolet (UV) radiation from sunlight or artificial sources such as tanning beds.
The name melanoma derives from the skin cells called melanocytes. Melanoma is the only type of skin cancer which develops from melanocyte cells, which are one of the three main types of skin cells in the epidermis, the top layer of skin. When functioning normally, melanocytes produce the pigment melanin, which protects the skin from sunburn/UV light and gives the skin and hair their coloring.
The production of melanin causes the changes in the skin that typically occur after exposure to UV radiation, usually from sunlight. These changes may include tanning, moles, freckles and patches where the skin lightens and/or darkens unevenly. These changes are, in most instances, benign. However, excessive exposure to UV radiation can cause changes in the DNA in the melanocyte cells, so that rather than producing healthy quantities of melanin, they grow and reproduce uncontrollably, becoming cancerous.
Even if the changes to one’s skin appear healthy, such as in the case of a tan, exposure to UV radiation can cause melanoma to develop later on. People with fair skin, red or blond hair, and those who spend a lot of time in strong sunlight, are at higher risk of developing melanoma than those with darker complexions.
The diagnosis of melanoma is confirmed by taking a sample (biopsy) for testing. Treatment and prognosis both depend on the level of advancement of the condition at diagnosis; the earlier melanoma is detected, the better the probable treatment outcome. If diagnosed early, surgery to remove the skin tissue affected by melanoma in its entirety may cure a person of this condition. If diagnosed at a later stage, when the melanoma has spread to a greater area of skin and/or internally, chemotherapy is often necessary.
Avoiding prolonged periods of sun exposure, as well as exposure to other UV radiation such as tanning beds, is the best means of preventing melanoma.
Good to know: Always seek medical attention if melanoma is suspected. However, most of the changes that occur to the skin as a result of sun exposure, such as the appearance of new freckles and moles, are not indicative of melanoma:
- See this resource on benign moles for more information about the various types of non-cancerous skin growths.
- See this resource on signs of melanoma for more information about spotting skin and mole abnormalities that may indicate melanoma.
Melanoma can develop anywhere on the body, including under the nails and toenails. The condition usually first appears on the skin ‒ in moles or the skin itself ‒ but can spread internally. Melanoma can usually be detected by monitoring changes to the skin, which often occur in areas that are frequently exposed to the sun such as the arms, legs, face and back.
Early signs of melanoma include a change in an existing mole or the development of a new, dark spot, mole or freckle on the skin. These moles are often asymmetric, have an irregular border, and they may change in color, get bigger or change in some other way. Hidden melanomas may occur on soles of feet, palms of hands, in fingernail beds or in the mouth, eye and digestive or urinary tract.
The four main types of melanoma in skin are:
- Superficial spreading melanoma: This is the most common type of melanoma, most commonly affecting the skin on the chest, back and limbs.
- Nodular melanoma: This is the second most common type of melanoma and can metastasize (spread) rapidly. It is most likely to be found on the chest, head, neck and/or back, and tends to redden, rather than darken, as it advances.
- Lentigo maligna melanoma: This is a slow-growing, rarer type of melanoma which most often affects older people who have spent long or intense periods of time exposed to UV radiation. It develops from a precancerous skin blemish called a lentigo maligna which looks like a liver spot or stain.
- Acral lentiginous melanoma: This is the rarest type of skin-based melanoma and is also described as hidden melanoma. It usually occurs in unexpected areas such as the palms of the hands, soles of the feet or the fingernail and toenail beds, and most commonly affects people with darker skin. It is not thought to be related to sun exposure.
It is also possible for melanoma to develop without initially causing any changes to the skin. Forms of melanoma which do not usually first result in skin changes include:
- Ocular melanoma, in the eyes
- Mucosal melanoma, in the nose, mouth, vaginal or anal passages
- Internal melanoma, where the cancer grows or develops inside the body without first exhibiting any visual indicators on the skin
See this resource on signs of melanoma for information about the differences between melanoma in moles and melanoma on the skin, and the specific signs of each type of melanoma.
Symptoms of melanoma in children
Melanoma in children is rare, affecting only around 300 children per year on average in the U.S. As with adults, children with fair skin and red or blond hair are at greater risk of developing melanoma than children with darker complexions. In children, the blemishes that indicate melanoma are often different to the signs of melanoma in adults. They are primarily paler: yellow, white or pink sores or bumps on the skin that bleed, itch or do not heal are the most common sign of melanoma in children.
As with adults, diagnosing melanoma in children as early as possible in its development is key to increasing the likelihood of successful treatment.
Causes and risk factors
The primary cause of melanoma is thought to be exposure to ultraviolet (UV) radiation. There are a number of genetic and personal factors which render it more likely that a person develops melanoma. These include being fair-skinned and/or being prone to developing moles. People who have already been diagnosed with melanoma on one occasion are also more likely to develop the condition again.
The primary cause of melanoma is believed to be exposure to a type of ultraviolet (UV) radiation called UVB radiation. People who use tanning devices that involve UV radiation, such as sunbeds, or who spend long periods of time in the sun, particularly during childhood, should be aware that they are at increased risk of developing melanoma and should perform monthly body scans to check for associated skin abnormalities.
Sources of UV radiation which may contribute to the development of melanoma include:
- Ultraviolet nail curing lamps
- Sun lamps
- Bactericidal lamps
- Black light lamps
Limiting the extent of one’s exposure to UV radiation by taking adequate precautions to protect the skin, such as wearing a high-factor sunscreen lotion and avoiding tanning treatments that involve UV radiation, can help to reduce the likelihood of developing melanoma. People who have experienced severe or frequent sunburn during childhood are at increased risk of developing the condition later on.
- Construction workers
- Agricultural workers
- Salon workers
- Airline staff, particularly pilots
- Lighting technicians
- Dentists and assistants
- Office workers, due to fixed seating, sometimes in direct sunlight
Factors in a person’s medical history that indicate an increased risk of developing melanoma include:
- A medical history of developing cancerous or precancerous moles
- A previous diagnosis of melanoma
- A weakened immune system, such as is caused by an autoimmune disease, or human immunodeficiency virus (HIV)
- A previous or current diagnosis of another form of skin cancer such as basal cell carcinoma or squamous cell carcinoma
- A previous or current diagnosis of any other kind of cancer
There has not been sufficient collection of data to verify the widespread conception that people with a family history of melanoma are more likely to be affected by the condition.
Skin type and coloring
- Red or blond hair
- Fair skin
- Skin which is sensitive to the sun and/or unable to tan
- Skin which develops freckles in the sun
- Blue or green eyes
Mole distribution and development
People with certain complexions, or with a tendency to develop certain types of moles, are at increased risk of developing melanoma.
- Having atypical moles
- Having large moles
- Having over 50 moles
- Regularly developing new moles after exposure to UV radiation
See this resource on benign moles for more information about how to identify whether a mole is non-cancerous or a potential cause for concern. Always consult a doctor if unsure about whether a mole has changed.
Diagnosis of melanoma
Diagnosing melanoma as early as possible in its development greatly increases the chances that it can be treated effectively and that a person can make a full recovery.
Due to the fact that potentially cancerous moles may turn out to be benign and that many symptoms of melanoma are also symptomatic of other conditions, melanoma can be difficult to diagnose. It is therefore important to consult a medical professional if one suspects one might be affected by melanoma, so that the diagnostic process can begin, especially if one is at increased risk due to being fair skinned, having experienced significant exposure to UV radiation and/or having a family of history of melanoma.
After performing a physical examination and taking a person’s medical history, the doctor will usually next perform a biopsy (tissue analysis) of the area where the melanoma is suspected. The procedure involves removing tissue from the skin and may involve the removal of an entire mole or skin growth. The sample will then be analyzed for the presence of melanoma.
A biopsy to detect melanoma is most often carried out by a type of skin doctor called a dermatopathologist. A report on the characteristics of the sample will be produced to enable the doctor to determine the presence of melanoma and the possible extent to which it may have advanced. The doctor will then strategize the most appropriate treatment plan for the affected individual.
There are several different kinds of skin biopsy, including optical, shave, punch, incisional and excisional biopsies, which can be used to test for melanoma. These involve different methods and extents of removing the skin. The doctor will consider factors like an individual’s age, the location of the suspected melanoma on the body and the size of skin area which will need to be removed. It is important to remove as much as possible of the area that is thought to be affected by melanoma in order to maximize the probability of making an accurate diagnosis.
In cases where the likelihood of a confirmed diagnosis of melanoma is moderate to high, doctors will use an excisional biopsy where possible, as this method makes it possible to remove the suspected tumor in its entirety. Excisional biopsies are ideal in cases where the melanoma is thought to be confined to a small area of the body, and are not viable in cases where the melanoma is thought to affect a large area of skin or to have already spread to other areas. If the melanoma is believed to have spread, a different kind of biopsy will be carried out to gauge its stage of advancement.
Identifying the stage (advancement) of melanoma
Once a diagnosis of melanoma has been made ‒ or if melanoma is already suspected to have become metastatic before the initial diagnosis is made ‒ the doctor will need to determine the stage to which the condition may have advanced. This involves discerning how big the melanoma is/are and whether it has spread to other areas of the body, including internal organs and lymph nodes.
The lymphatic system is a crucial element of the body’s immune system. Lymph is interstitial fluid which, in healthy people, bathes the body’s cells in essential substances like protein, blood plasma and oxygen. When lymph passes through the lymphatic system to reach the lymph nodes, bacteria, viruses and cancer can be detected. Many types of cancer, including melanoma, can spread through the lymphatic system. The presence of melanoma in the lymph nodes therefore indicates the potential spread of the cancer to other areas of the body.
Finding out whether the cancer has already spread to other areas of the body is crucial in order to determine the prognosis, i.e. how likely and how fully a person is to recover, and the most appropriate course of treatment. The kinds of biopsies used to determine the spread of melanoma are often more extensive than those that analyze a specific area of skin.
When determining how far a cancer has spread, a Roman numerical system will be used to rate the severity of the cancer from the least advanced stages 0 and I (1), through to cancers which have already spread greatly ,stages III (3) and IV (4). Hereafter, in this resource, the stages will be referenced with Arabic numerals.
Having established the overall stage, doctors will then grade the condition alphabetically (A-C) depending, again, on characteristics that relate to its severity.
The lower their melanoma is rated, the better a person’s prognosis will be. For example, stage 1A melanoma has a five-year survival rate of 97%, meaning that 97% of people with melanoma survive for a minimum of five years and possibly many more after diagnosis, whereas stage 1B melanoma has a five-year survival rate of around 92%.
Biopsies to test the stage of melanoma may include:
Fine needle aspiration (FNA) biopsy
This procedure involves removing a sample of fluid or tissue from the area just under the skin with the use of a fine needle. It can usually be carried out under local anesthetic with no complications. FNA is considered to be one of the most rapid and accurate ways to examine the possible metastasis (spread) of suspicious lesions. When testing for melanoma, doctors will look for changes to the lesion’s cells, such as altered cell shape.
Excisional lymph node biopsy
Alteration in the sensation and shape of the lymph nodes is a possible indicator of the spread of melanoma. An excisional lymph node biopsy is a surgical procedure which involves removing all or part of a lymph node that has become suspicious. Analysis will reveal whether the changes are due to the spread of melanoma.
Local or general anesthetic will be used before an incision is made in the skin near the lymph node, and the relevant section of the lymph node is removed for analysis. The surgical site will be closed with a suture.
Sentinel lymph node biopsy
Sentinel lymph node is a term used to describe any lymph node to which the cancer is most likely to spread first. In a sentinel lymph node biopsy (SLNB), the relevant node will be identified, removed and assessed for the presence of melanoma. It is possible for a person to have more than one sentinel lymph node, and an SLNB procedure may involve the removal and analysis of one or more sentinel lymph node(s).
During the procedure, radioactive material and/or a colored dye will be injected at the site of the melanoma and a device that detects radioactivity will be used to identify the sentinel lymph node(s), which can then be surgically removed. A negative result of an SLNB test, in which no lymph nodes are detected to be radioactive and/or become colored by the dye, implies that the melanoma has not yet spread to the lymph nodes. This enables doctors to deem it unlikely for the melanoma to have reached other areas within the body.
Treatment and management
The treatment approach required for melanoma depends on the extent to which it has spread. It may be possible to remove the entirety of the affected area(s) with surgery. However, melanoma that has spread to multiple sites or advanced within the body may require a combined approach.
Treatment options for melanoma will depend on the overall health of the individual, their specific medical circumstances and the advancement of their melanoma. After melanoma has been removed, if this is possible, periodical screenings are often necessary in order to check whether melanoma has come back (recurrent melanoma). This is carried out with MRI and/or CT scans, and is called surveillance imaging.
Recurrent melanoma after successful treatment for early-stage melanoma is rare, but possible; people who have already been affected by melanoma are at greater risk of melanoma than the general population. Consult the medical staff involved in the treatment for a personalized estimate of the likelihood of recurrent melanoma.
People who have been treated for advanced melanoma are particularly encouraged to call their doctor to arrange a check-up or scan if they are worried about anything related to their health. The likelihood of melanoma returning increases the more advanced a person’s melanoma is when they begin treatment.
Treatment for melanoma may include any, or a combination, of the following approaches:
Wide excision surgery
This type of surgery can usually be performed under local anesthetic as an outpatient procedure. It involves cutting away the mole or area of skin affected by melanoma in its entirety, as well as a band of healthy skin around the edge of the affected area. The size of skin removed depends on the thickness of the melanoma, and where the affected area of the body is.
In some cases, a skin graft, i.e. healthy skin taken from another area of the body, will be used to cover the skin removed during wide excision surgery.
Lymph node dissection (surgery to remove the lymph nodes)
If melanoma is found in the lymph nodes; i.e. a sentinel lymph node biopsy is carried out and the results are positive; this kind of surgery will remove the lymph nodes to which melanoma has spread.
Usually carried out under general anesthetic, lymph node dissection involves making an incision in the area where the infected lymph nodes are, e.g. the armpit or groin. Careful monitoring during recovery is needed to prevent complications such as lymphedema; the buildup of undrained lymph in the area where the nodes were removed.
As an adjuvant (additional) treatment to lymph node dissection, some doctors will recommend an immunotherapy treatment called interferon alpha (IFN-α), targeting the area where the melanoma had infected the lymph nodes.
Adjuvant treatments are therapies prescribed in addition to the primary procedures, aimed to help lower the chances of recurrent melanoma. Periodical check-ups will be scheduled after surgery in order to ensure that the affected person is recovering properly, to prevent complications and to screen for recurrent melanoma (melanoma that returns) and new melanomas. These follow-up appointments will usually be scheduled to take place every two to three months, and annually after five years have passed.
If melanoma has advanced to another area of the body, for example, an organ or another area of skin, this is called secondary melanoma. It may be possible to remove the secondary melanoma via a surgical operation, depending on where in the body it is. A person’s medical care team will assess criteria such as how likely the surgery is to be successful, and whether the affected person is otherwise fit and healthy enough to undergo the necessary procedure, before recommending this approach.
Surgery is most likely to be carried out when melanoma is believed to have spread to only one other site in the body, rather than multiple areas.
Also known as radiotherapy, radiation therapy kills cancer cells using high-energy waves. This treatment is usually carried out to treat melanoma which has spread. It is not usually used at the primary site, except in cases where surgical removal of the melanoma is considered unsuitable for the affected person.
When it is recommended, radiation therapy is most often used to treat the following types of secondary melanoma:
- Melanoma in the skin
- Ocular melanoma
- Mucosal melanoma
Radiation therapy can also be recommended as a preventative measure after surgical removal of melanoma, to help reduce the risk of recurrence.
This is a fairly new treatment for melanoma, which is an innovation on standard chemotherapy medications. These approaches are usually used to treat melanoma which has spread, and/or in cases where surgery is not feasible, or has been unsuccessful.
Targeted therapy is considered to be more effective for treating melanoma than chemotherapy, which kills all quickly dividing cells. Like chemotherapy, targeted therapy is systemic. The medication is infused into the bloodstream intravenously, and travels throughout the entire body.
However, unlike chemotherapy, targeted therapy is designed to target only the parts of cancerous cells that make them different from normal cells, shutting them down. Due to this difference, targeted therapy also has less severe side-effects.
Chemotherapy will usually only be offered in order to treat advanced melanoma which has not responded well to other treatments. Newer types of biologic treatment, such as targeted therapy, will usually be recommended first. Chemotherapy is systemic, meaning that it circulates throughout the body via the bloodstream, and the side-effects can be severe, including nausea, hair loss, fatigue, and a compromised immune system which results in increased susceptibility to infections. For more information, see this resource on chemotherapy side-effects.
Good to know: It is possible to undergo regional chemotherapy, in which the chemotherapy drug used is confined to a limb, rather than circulating throughout the rest of the body. This generally minimizes the side effects of the chemotherapy. Regional chemotherapy can be carried out if the the recurring melanoma develops in an arm or leg, very close to the primary melanoma.
Clinical trials for new treatments
Research is continually being carried out in order to develop new treatment methods that may be more effective than current ones at treating melanoma that has spread significantly. People with stage III or IV melanoma may wish to take part in a clinical trial in order to access the latest treatment innovations. More information about clinical trials can be found in this resource from the American Cancer Society.
Being sunburnt intensely or regularly, even at a young age, is a risk factor for developing melanoma in adulthood. For this reason, it is important that all people, even newborn babies, are protected against sun damage. Actions that can help reduce a person’s risk of melanoma include:
- Covering up the skin with protective clothing when spending time in the sunlight, including wide-brimmed hats, t-shirts and UV-protective sunglasses
- Always wearing a sunscreen with broad spectrum protection, against UVA and UVB rays of sun protection factor (SPF) 30, or above
- Using a water-resistant sunscreen when swimming or during high-intensity activities, such as sports
- Avoiding tanning, especially UV tanning beds
- Seeking shade, especially between 10AM and 4PM
- Taking extra care to wear adequate sunscreen in reflective environments; sea, snow and sand all magnify the effects of harmful UVB radiation
- Being aware that certain medications can leave a person more vulnerable to sun damage; always check the guidelines of any new medications and consult a doctor about the risks of sun exposure
- Examining the skin once a month for signs of melanoma
- Consulting a doctor yearly for a professional skin examination
Q: Can melanoma return after successful treatment?
A: The sooner melanoma is diagnosed in its development, the less it will have spread before treatment begins and the smaller the risk that it will return. For example, Stage 0-I melanomas are most often fully treatable and unlikely to return, whereas the likelihood of Stage IV melanoma returning is greater. When melanoma returns, this is called recurrent melanoma. There are two situations in which a person may experience recurrent melanoma:
- Due to initial treatment for melanoma having been inconclusive, i.e. some cancerous cells have remained in their body.
- Following successful treatment of the initial melanoma, a person can develop new, local outbreaks of melanoma.
People who have a medical history of melanoma and/or other types of cancer are more likely to develop recurrent melanoma than those who do not. A person’s treatment plan for recurrent melanoma will usually involve one or more of the treatment options for initial melanoma, and will depend on where in the body the melanoma has spread to, and how far it has advanced.
Q: What happens if a person develops melanoma during pregnancy?
A: According to the American Academy of Dermatology, melanoma can in some cases be safely treated during pregnancy. If melanoma is diagnosed in the early stages, it can be removed using local anesthetic, which does not pose health risks to the developing baby. The sooner melanoma is diagnosed, the easier it will be to treat the expectant mother without posing risks to the baby. This is because most of the treatment methods that are used to treat advanced melanomas are not recommended for pregnant people. For example, radiation therapy is only recommended for treating the head and neck of pregnant women; if it is applied to the pelvic area, there is a risk of birth defects. Always consult a doctor if melanoma is suspected, to help ensure that it can be detected and treated promptly.
Q: Can a baby be born with melanoma, if the mother is affected during pregnancy?**
A: It is very rare, but possible, for a baby to be born with melanoma. It is an unlikely outcome even if a mother has stage IV melanoma during pregnancy, but it is possible because melanoma can cross the placenta; the organ which transmits nutrients and carries waste away from the fetus in the womb. If a pregnant person is being treated for melanoma, the placenta should be examined after birth. if melanoma is detected, the baby should receive regular check-ups from a dermatologist.
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