What Is Mucosal Melanoma

The word “melanoma” represents the most severe form of skin cancer. Even though it only covers 0.03% of cancer cases, it is a highly deadly type of cancer.^1,2 Whereas ‘Mucosal’ represents less frequently occurring melanoma skin cancers.³ 

UV light is a common factor which causes skin cancers. However, mucosal melanoma occurs on your skin without being influenced by exposure to UV light.⁴ This is the key difference between other skin cancers, such as cutaneous melanomas and mucosal melanomas. 

Mucosal melanoma has been found to appear on your membranes, a highly sticky substance called mucous.⁴

Factors such as your age, ethnicity, and gender can determine your risk of having mucosal melanoma, which can also affect your chances of living with the disease. 

Therefore, if you are aware of the risks, you can take precautions to improve the quality of your life. 

The following sections will further explain these factors and the management of these details to develop your awareness of this topic further.

Risk factors

There are several risk factors that are linked to mucosal melanoma formation:^1,4,5

• Smoking
• Inhaling/ingesting tobacco-containing products and other carcinogens (substances or agents that can cause cancer formation)
• Exposure to chemical irritants - this can cause inflammation on your skin as well as mucosal melanoma. These chemical irritants can be found in your house cleaning, self-care or industrial products.
• Viral infections - such as HIV. However, this still remains controversial among the scientists.
• Chronic inflammatory diseases
• Age -over 65% of the patients are above the age of 60.
• Ethnicity 
• Gender - people assigned to women at birth are higher in diagnosis rate than people assigned to men at birth.

Survival rates

Unfortunately, mucosal Melanoma is a very lethal disease with a 5-year chance of survival after diagnosis lower than 25%.

The size of your tumour does not determine your chance of survival in mucosal melanoma.⁶ However, the location of your tumour affects your survival rate - it can either increase or decrease your chance of survival. 

Detection of cancer at its later stage can decrease your chance of survival.⁷ Therefore, regular check-ups accompanied by early diagnosis can help you improve your quality of life. This is dependent on the specific group of mucosal melanoma you are diagnosed with.

Sites of tumour formation

The primary location of a cancer is the place where the tumour first occurs. The secondary site is where it is located after it metastasises (movement of cancer cells to various locations around your body) when it progresses. The primary sites of melanoma:^5,8

• Oral cavity 
• Oesophagus (the tube that connects the mouth and stomach)
• Rectum (last section of your large intestine)
• Anal canal (connects rectum with the outside of the body where faeces are get rid of)
• Nasal cavity (includes all the area inside your nose)
• Cervix (narrow passage between your womb and uterus)
• Vulva (external part of vagina outside of the body)
• Reproductive organs such as the vagina or penis
• Urethra (tube where the urine exits the body from the bladder)
• Bladder 

These locations can be grouped into four main categories:^5,8

1. Head and neck mucosal melanoma (MM) - oral cavity, nasal cavity, oesophagus
2. Gastrointestinal MM - rectum and anal canal
3. Genital MM - cervix, vulva, penis, and scrotum
4. Urinary MM - urethral and bladder. T

Depending on the location, the metastasis site can change. As an example, head and neck MM metastasize to the lungs and liver.^5,8 

Head and neck MM is the most common type and occurs in over 50% of MM cases. Whereas genital MM is the least prevalent MM.⁸

Symptoms

Understanding the symptoms of mucosal melanoma is important for detecting signs and allows you to seek help for further evaluation if needed. 

During the early stages of the disease, most of the signs are hidden.¹ 

Although, as the disease develops, there are several symptoms of MM, depending on its location, such as in:⁵ 

• Nasal MM: Usually, nose bleeding, lump formation, or blockage of the airway can be experienced. However, on some occasions, there may be symptoms of double vision, change in the appearance of the face and either swelling or protrusion of the eyeball(s) outside of the eye pockets.
• Oesophagus MM: the most common symptoms are weight loss and feeling an ache behind your breast bones. Even though they are rarely observed, few can experience vomiting blood or dark stool.
• Rectal NM: these symptoms include rectal bleeding, the formation of a mass on the anus (the last part of the rectal canal) and pain in the rectal canal.
• Vulvar MM: bleeding, vulvar mass, pain, burning while urinating, severe itching of the skin.
• Vaginal or cervix MM: they have similar symptoms such as vaginal discharge, vaginal bleeding, lump on the vagina and pain inside the vagina.
• Oral MM: it has no symptoms at an early stage, but as it progresses, the symptoms can arise as instability of teeth, pain, swelling, bleeding and wounds around the oral cavity.

You should seek help from health professionals as soon as you feel like you are displaying symptoms, as early detection can improve your quality of life. 

Diagnosis

It is particularly important to diagnose MM early before the symptoms arise because early onset tends to lack symptoms. Hence, if you have family members diagnosed with the disease, if you are exposed to chemicals or smoking - regular checks are strongly advised. Common diagnostic methods include:

• Biopsy (removal of the lump, or part of the lump, or section of the skin lesion sent to a laboratory for diagnosis)
• Blood test (to look for cancer proteins in your blood)
• PET scan
• MRI scan
• CT scan

Treatment options

Treatment is decided by your doctor and health professionals, depending on your individual case and health conditions. The most common treatments currently in use for MM patients include:^2,9,10

• Chemotherapy - uses chemical drugs to kill cancer cells
• Surgical resection - removal of cancer cells and surrounding tissue to prevent reoccurrence of cancer
• Immunotherapy - uses our immune system to help fight cancer cells
• Electrochemotherapy - electric pulses are used to deliver chemotherapy drugs to cancer cells, which allows for more precise targeting of cancer cells only so it doesn’t kill other healthy cells in the body 
• Drug treatment - may involve drugs that specifically cancer cells or cells that cancer cells produce 
• Radiotherapy
• Monoclonal antibodies
• Signalling inhibitors
• Clinical trials 
• Genetic testing

If your doctor decides that the currently available treatments will not benefit you then you can apply for clinical trials. During clinical trials, a new drug currently being assessed can be applied to you, and the prognosis of your disease can be observed. 

Additionally, genetic testing can determine the presence of mutated genes and proteins specific to your cancer type to predict better which smart drug can target specific abnormalities in your body.¹⁰

Furthermore, surgery is the most common treatment during the initial stages, where the tumour or the lesion is removed along with the extra tissue to prevent remnants of any cancer cells.⁹ 

After the surgery, immunotherapy or drug treatment is applied to ensure the cancer cells have been killed.^2,9 

Current research and hope

mRNA vaccines have been evaluated as cancer vaccines to see whether they will be able to treat various. However, there is still a lot of research left to be done, so success rates have been low. A type of mRNA vaccine for cutaneous melanoma is under clinical trial and has already shown promising results.⁸ 

Therefore, this gives us hope for future treatment of mucosal melanoma patients in the hopes of improving their quality of life. 

Conclusion and summary

Despite having a low prevalence rate, mucosal melanoma is highly lethal and requires further research to fully understand the behaviour of the disease. 

This can help us find better treatment methods. However, certain precautions can be made to improve your chances of early diagnosis to prevent the disease from developing further. 

For example, avoiding smoking using chemical cleaning products with precaution can help. 

If you ever feel like you may be showing symptoms of MM, make sure you contact your healthcare professional, who can guide you further.