Malignant Melanoma

What is Melanoma?

Melanoma, also known as Malignant Melanoma is a type of cancer of the melanocytes; which are pigment forming cells contained predominantly in the skin.

Melanoma can arise from a long standing mole or de novo (in an area with previously normal skin).

Melanoma can occur anywhere on the body but is most commonly found on the sun-exposed areas. The primary cause of Melanoma is sunlight (UV radiation). UV radiation can cause sunburn. Sunburn is a sign of damage occurring to the DNA in the skin cells. Repeated DNA damage can cause cells to grow out of control and lead to cancer. 

Changes in a mole that could indicate that they are becoming abnormal include; change in size, shape, colour or symptoms. Symptoms can include bleeding and itching. The ABCDE signs are routinely used as warning signs of when to seek a medical opinion. A Melanoma may show all of these signs or none of these signs, but if you are concerned it is always best to seek an opinion from someone trained. There are a number of different subtypes of Melanoma. These include superficial spreading, nodular, amelanotic and subungal. 

Asymmetry

Asymmetrical lesion shape

Border

Irregular border

Colour

Multiple variations of colour

Diameter

Increased size (>6mm)

Evolving

Changing size/shape/colour

Diagnosis and Staging

In order to diagnosis Melanoma, the mole itself will be removed with a narrow border of normal tissue. This will diagnose whether it is a Melanoma, the subtype of Melanoma, whether it has been fully removed and the thickness of the tumour (known as the Breslow thickness). 

Following a consultation with a Melanoma specialist, the type of Melanoma and plan for further treatment will be discussed. First line treatment of Melanoma of the skin can include a wider excision of the Melanoma scar and a Sentinel Lymph Node Biopsy (SNB). A wide excision of the scar aims to reduce the chance of the Melanoma coming back at that site. A SNB aims to establish whether the Melanoma has already spread to your lymphatics local to that scar. A SNB can be offered to those patients with a Breslow Thickness of >1mm if deemed appropriate by yourself and the operating surgeon. If the SNB is negative it puts you into a lower risk group of having a recurrence in the future. If the SNB is positive it puts you into a higher risk group which may suggest further treatment is required. 

Further treatment of Melanoma in patients with a positive SNB (i.e. evidence of Melanoma in the SNB) can include drug treatment (systemic anti cancer treatment). At present this treatment is categorised into immunotherapy and targeted therapy. Immunotherapy aims to boost your immune system to recognise Melanoma cells that are hiding in the body and attack them. In most centres targeted therapy currently is offered to those with a BRAF mutation. A BRAF mutation occurs in around 40% of patients with Melanoma and can be used as target for BRAF Inhibitors. Those patients without a BRAF mutation and therefore can not usually have targeted therapy are referred to as having a BRAF wildtype Melanoma. If systemic anti cancer treatment is required these will be discussed at length by the Oncology team. A CT Scan tends to be performed before these drugs are given to check for any evidence of any cancer in the rest of the body. When drugs are used following SNB they are referred to as being in an adjuvant setting. This essentially means, that there is no evidence of any Melanoma left in the body, but the is aim to treat small areas that may be in the body but not currently detectable on a scan.

The Future

The treatment of Melanoma is changing every day. The regimen of drug treatments and the drugs that are available continue to evolve. This means the literature available to you may have changed by the time it is published. It may also mean that one patient in the waiting room may have had or be on a different treatment to you. Please discuss with your specialist the most up to date information

Some patients who present with evidence of Melanoma in their lymph nodes require a lymph node dissection; this includes patients who present with a lump in a lymph node basin (usually axilla, groin or neck), those who have had a scan which demonstrates a lump and is confirmed to be Melanoma or in a small number of patients who have had a positive SNB. This is essentially removing all of the lymph nodes in that area of the body; axilla, groin/pelvis or neck. 

A lymph node dissection takes between 1 - 3 hours depending on the complexity and site but tends to have standard risks. These include normal surgical risks (scar, bleeding, infection, and problems with wound healing) and those specific to a lymph node dissection. These are nerve injury, seroma (collection of fluid following surgery) and lymphoedema (swelling of the limb following surgery). As the lymphatics essentially drain fluid from their adjacent limb, the surgeon will put a drain (tube connected to a bag) after surgery. This can be in for a number of weeks, but does not mean you need to stay in hospital for this time. Despite this intervention fluid can still collect after surgery or in the limb until the body works out how to deal with this new fluid demand. Following surgery most patients will be referred to the Oncologists for further drug treatment. 

Patients with more advanced disease, referred to as unresectable Stage III (in a localised area but no longer operable) or Stage IV disease are often referred for Systemic Anti Cancer treatment. The drugs can be similar in nature to the drugs referred to above but are often given in a different regimen to the previous 'adjuvant' setting. 

​Alternative Treatments

There are a number of additional treatments that can be used in Melanoma depending on the type of Melanoma and site. These will be discussed by your Melanoma team. Some of these treatments include; Electrochemotherapy (ECT), Isolated limb infusion (ILI)/ Isolated limb perfusion (ILP) and TVEC.

Electrochemotherapy

Is a technique of delivering chemotherapy to Melanoma cells using electroporation. Electroporation uses an electrical current to make the Melanoma cells more permeable to chemotherapy; essentially temporarily breaking down the wall of the Melanoma cell and allow drugs to infiltrate. This may require a general anaesthetic (asleep) but in many cases can be performed as a daycase local anaesthetic (awake, with injections only). 

ILI, ILP

An alternative means of delivering high concentrations of chemotherapy to the Melanoma by isolating that limb with a use of catheters (large needles) or direct into the vessels in that limb and a tourniquet. This surgery tends to a take a few hours under a General anaesthetic and is only performed in a few centres in the United Kingdom. It is usually suitable for those patients who have disease in a limb which is not surgically resectable (can't be cut away) and can lead to significant improvement of the disease in that limb.

TVEC

Again usually given to those patients, where the disease can not be surgically removed. TVEC involves local injection of immunotherapy. Your Melanoma specialist will only this to you if you are suitable. 

Radiotherapy

Not a mainstay treatment in Melanoma but can be indicated in those patients with unresectable disease for symptom control.

Melanoma resources

Melanoma Focus UK - https://melanomafocus.org/

Cancer Research UK - https://donate.cancerresearchuk.org/

DermNet NZ - https://dermnetnz.org/

The following resources are not affiliated with this website but provide uptodate information on Melanoma and non-Melanoma Skin Cancer.