What is melanoma?
Melanoma is a form of skin cancer, that originates in the skin's pigment cells (melanocytes). In a melanoma skin cancer melanocytes become malignant and increase in number. An important cause of melanoma is excessive exposure to ultraviolet light both from sunlight and sunbeds.
Melanocytes make a brown/black pigment (known as melanin), therefore the first sign of a melanoma can be an existing mole changing colour or development of a new brown/black lesion. Most commonly the pigmented lesion becomes darker in colour but rarely there can be loss of pigmentation with pale areas or red areas of skin developing. This melanoma on the skin is known as the primary melanoma.
Melanoma is often thought to be the most serious type of skin cancer because it is more likely to spread (metastasise), from the skin to other parts of the body, than other types of skin cancer. If melanoma spreads to other parts of the body, this is known as secondary melanoma or metastasis.
Diagnosis and initial treatment
Melanoma can be serious, however the majority of melanomas are caught at an early stage and once removed do not cause any further problem. If a melanoma is not caught early, then there is a greater risk of the melanoma spreading to other parts of the body, which can reduce life expectancy.
If a pigmented lesion is suspected to be a melanoma, the initial treatment is to cut out (excise) the whole lesion. This first excision surgery is to find out if it is a melanoma or not, and if it is a melanoma how thick it is, so the lesion is excised with a narrow margin of normal skin surrounding it. The specimen is sent to a pathology laboratory, so it can be examined under a microscope. Pathologists will report if the lesion that has been removed is a melanoma and how thick it is. This is the only way a diagnosis of melanoma can be confirmed.
How is melanoma staged?
A staging system is used by doctors to convey melanoma severity which in turn gives an indication of both the prognosis and the best treatment. In the UK melanoma are described using stages 1 to 4. Stage 1 is the earliest stage of melanoma development and stage 4 is the most advanced. The stage is higher if melanoma from the skin has spread to other parts of the body.
Stage 1 and 2 melanomas are confined to the skin only and have not spread anywhere else in the body. Stage 3 and 4 melanomas have already spread to other parts of the body. The pathologist will look under the microscope to assess certain features of the melanoma. These include the Breslow thickness (named after the doctor who described it). The Breslow thickness is a measure of how deep into the skin the melanoma cells have grown (or invaded). The pathologist will also record a number of other characteristics of the melanoma when examined under the microscope. A pathology (histology) report is written which forms part of the staging process. Stage 1 is considered a thin melanoma. If you would like to know more, please discuss this in more detail with the consultant from London Skin Cancer Centre team who is looking after you.
What happens next?
The London Skin Cancer Centre is one of the few private clinics in London that have the full complement of doctors required to safely provide high quality skin cancer care. This is called a multi-disciplinary team and includes dermatologists, plastic surgeons, pathologists and oncologists. Our team discusses each melanoma skin cancer which allows consensus regarding the diagnosis and the best treatment option. One of the consultants will then explain the outcome of this multidisciplinary team meeting (MDT) and what the next step is.
How is melanoma treated?
Excision (surgical removal) of the melanoma results in the best chance of a complete cure, and this treatment alone is usually successful in stage 1 melanoma. Patients do NOT generally need either radiotherapy or chemotherapy.
Wide Local Excision Following removal of the melanoma and subsequent MDT, patients will usually be offered a second surgical procedure to remove more skin from around and underneath the melanoma scar. The size of the margin of normal skin removed from around the first operation scar depends on the characteristics of the primary melanoma, including Breslow thickness. This second operation is called a Wide Local Excision (WLE). The purpose of the WLE is to try and ensure no melanoma cells are left behind in the nearby skin.
What scar(s) can I expect following a wide local excision? The resultant scar will vary depending on the site and type of surgery. The WLE might result in a similar scar that is larger than the one created by the excising the original melanoma. However sometimes more complicated surgical techniques are used during the WLE; such as creation of a skin flap or graft, this will result in a scar with a more complex shape. This will be discussed by your surgeon prior to the WLE.
Regular follow up After a diagnosis of melanoma , it is important to have regular reviews with your Dermatologist. The exact frequency and duration of the follow up schedule will vary depending on the stage of the melanoma. With advanced melanoma, follow up may involve regular scans, but this is not the case in early stage melanoma. The intention of the follow up is to pick up signs of melanoma recurrence earlier but also to review the patient's other skin lesions at the same time in order to detect new skin cancers. If you wish to know more precisely the risk a particular melanoma recurring then please discuss this with the doctor looking after you.
Sentinel Lymph Node Biopsy (SLNB)
Following diagnosis of a thicker melanoma, patients may be offered a SLNB. This is an additional investigation to help determine the stage of the melanoma by assessing if it has spread from the original site to the nearest lymph node. If a melanoma does spread, it most commonly spreads to the nearest lymph nodes (also known as lymph glands). For example a melanoma on the leg can spread to the lymph nodes in the groin, or a melanoma on the back could spread to the lymph nodes either in the armpit or the groin. It usually goes to the closest lymph node. The melanoma cells in the lymph node may be so small that they cannot be felt, or seen on a scan, therefore the SLNB may be the most accurate way of detecting any spread of melanoma cells.
A SLNB will usually be undertaken at the same time as a WLE, under a general anaesthetic . A radioactive liquid is injected at the site of the original melanoma. A very small amount of radioactivity is used for this test which is of no risk to you or your close contacts. A scan is then carried out to see which node or nodes the liquid reaches. The first (or sentinel) node/s is identified. A blue dye is then injected at the same place as the radioactive liquid, which allows the surgeon to see the sentinel node/s more easily which can then be removed. The node/s removed are sent to the pathology lab where they are examined to assess for presence of any melanoma cells.
A positive SLNB is where melanoma cells are found in the lymph node. In this situation a further procedure is normally required where all the nodes in that areas are removed ; a procedure called a “completion lymphadenectomy or lymph node clearance”.
SLNB has both advantages and disadvantages and therefore currently is an optional procedure. In its favour is the greater information it gives the patient and doctor. A negative SLNB result can be reassuring and in this situation approximately 85% of patients will have no further trouble from the melanoma.
Following a positive SLNB result, the melanoma is then considered stage 3 disease and in this situation around half of patients may have a recurrence of the melanoma. A positive result may also make patients eligible for clinical trials of new drugs designed to improve prognosis. There is however no evidence so far that having a sentinel lymph node biopsy improves the chances of survival.
The disadvantages of SLNB are having to have a general anaesthetic and having an additional scar/s. Without a SLNB a WLE alone can often be done under local anaesthetic. Removing a lymph node may result in a localised accumulation of lymph fluid (a seroma) at the biopsy site, as the lymph drainage has been altered by the surgery. A seroma can take a while to settle down following surgery and rarely may persist.
What can you do to decrease the risk of melanoma?
1. Avoid sun burn.
2. Protect your skin with clothing and a wide brimmed hat.
3. Stay out of the sun between midday and 3pm.
4. Use factor 50 UVB sunscreen which also has a UVA circle logo and/or 4 or 5 UVA stars.
5. Use the sunscreen before going out in the sun, and reapply every two hours.
6. No sun screen will provide complete protection and they are no substitute for shade or clothing.
7. Keep babies and young children out of direct sunlight.
8. If you are concerned about a changing mole or non healing patch of skin consult your Dermatologist.
9. Consider taking Vitamin D tablets; as strictly avoiding sunlight can reduce Vitamin D levels.