Malignant melanoma (MM) is a malignant tumour arising from melanocytes, which are mainly found in the skin. Its incidence is increasing worldwide including in Malta. In 2017 the incidence was reported as 11 per 100,000 population per year.1

Cutaneous MM can arise from otherwise normal appearing skin (~70% of cases) or from an existing naevus (~30%). Melanoma can grow on any part of the body, however the most frequent site in males is the back, whilst in females the lower limbs. Rarely it can also arise on the nails, mucous membranes as well as the eye and brain.

The main risk factors for developing MM are:

  1. Previous history of MM
  2. Multiple atypical melanocytic naevi – these moles are often numerous, highly variable in terms of size, shape, colour and often larger than ordinary naevi
  3. Multiple melanocytic naevi
  4. Family history of MM in a first-degree relative
  5. Organ transplant recipients
  6. Those with giant congenital naevi
  7. Previous history of other skin cancers (basal cell carcinoma and squamous cell carcinoma).

CLINICAL FEATURES OF MELANOMA

In some patients MM can present as a changing lesion. In this scenario, MM has characteristics described by the Glasgow 7-point checklist.2 A score of 3 or more should prompt referral to a specialist.

Major features (2 points each):

  1. Change in size
  2. Irregular shape
  3. Irregular colour

Minor features (1 point each):

  1. Diameter greater than 7mm
  2. Inflammation
  3. Oozing
  4. Altered sensation

An alternative rule that can be used by health professionals and patients to check for the major warning signs of melanoma is the ABCD rule:3

  1. Asymmetry – two halves of the mole look different in terms of shape or colour
  2. Border – irregular, jagged or blurred borders
  3. Colour – two or more different colours or shades, or a single colour that is different to other naevi
  4. Dimensions – any change in size, either in diameter or degree of protrusion

Nodular MM, the most dangerous type of melanoma due to the speed at which it grows into deeper tissue, can lack the above characteristics so it is also important to always consider the EFG rule4 and urgently excise a lesion that manifests such features:

  1. Elevation, and
  2. Firmness, and
  3. Growth that is persistent for a month or more.

MANAGEMENT OF MELANOMA

The initial treatment for suspicious lesions should be prompt complete excision with narrow (typically 2mm) margins. Once an initial diagnosis of MM is determined on histology, further wide local excision is required, the extent of which depends on the staging.5

The staging of MM is mainly linked to the Breslow thickness (BT) of the tumour at presentation. This is a histological measurement determined by the pathologist and is measured in millimetres. It reflects how deep the tumour invades and is a strong predictor of prognosis. The thicker the melanoma the more likely it is to metastasise.

The following table guides the multidisciplinary team as to the extent of wide local excision. Anatomical location can mean such margins are not always achievable.

Melanoma in situ             5mm

Melanoma                          <1mm BT 10mm Melanoma 1-2mm BT 10-20mm Melanoma >2mm

BT                                           20mm

Further staging may involve sentinel lymph node biopsy. This procedure involves lymphatic mapping in order to identify the first downstream node from the MM. This is generally reserved for MM over 0.8mm BT. If the sentinel node is positive, removal of the entire lymph node basin is usually offered as well as further imaging to determine the extent of metastasis. In recent years targeted molecular therapy and immunotherapy have revolutionised the treatment of metastatic MM. These treatment details are outside the scope of this article.

LONG-TERM MANAGEMENT OF MELANOMA

A vital aspect of melanoma management is patient education. Reducing their future risk through avoidance of excess ultraviolet radiation can be challenging particularly whilst living in a country like Malta. Below are key messages for your patients:

  1. Wear long sleeves, trousers, hat and sunglasses when outdoors. Ideally the clothing is tight-weaved or has an ultraviolet light protection rating.
  2. Seek shade during peak hours of the day e.g. 11am – 3pm; consider directing patients to the UVLens App6
  3. In addition to the above use sunscreen habitually. It should be at least SPF 30 with UVA cover too. Sunscreen needs to be reapplied every 2 hours as well as after swimming.

Regular ongoing follow-up is also very important particularly during the first five years after diagnosis. This allows for the earliest possible detection of locoregional recurrence but also the diagnosis of a second primary melanoma. The literature suggests a subsequent melanoma develops in up to 20% of patients.7 The aim is to detect MM as early as possible when the degree of invasion is at its thinnest. However, a major clinical challenge is finding an acceptable balance between identifying early-stage melanoma whilst avoiding too many biopsies/ excisions which are associated with a number of morbidities. Such decision-making is particularly difficult in patients with multiple atypical naevi.

Total body photography (TBP) facilitates the identification of new or changing lesions particularly in those with atypical naevi and has been shown to reduce the number of biopsies.7 Taking such images in an automated fashion enables the creation of a standardised image collection for each individual patient. This is useful for future clinic visits and also as a reference for the patients themselves to facilitate and encourage regular self-skin examinations.

In a 5-year cohort study of 977 patients with a history of melanoma, 48% of second melanomas were identified by TBP.7 Furthermore, a study of high-risk patients saw a 3.8 fold reduction in biopsies after the incorporation of TBP in their follow-up.8 This is important to avoid the potential complications associated with such procedures including infection with consequent antibiotic use, scarring and psychological trauma as well as economic costs. The use of TBP has also been shown to reduce cancer worry and as a result improve quality of life and adherence to screening.9

Dermoscopy, otherwise known as epiluminescent microscopy, is now considered standard practice in the examination of pigmented lesions. It is also increasingly used to aid diagnostic accuracy for non-melanocytic lesions and inflammatory dermatoses. It relies on a high-quality magnifying lens and a powerful lighting system in the form of a dermatoscope.

Dermoscopy use by trained clinicians improves diagnostic accuracy for melanoma compared with visual inspection alone.10 Furthermore, sequential digital dermoscopic imaging permits longitudinal dermoscopic monitoring. It is particularly useful for suspicious lesions, which do not have sufficient criteria to warrant excision biopsy. Three-month dermoscopic follow[1]up offers a safe alternative as it allows for close short term[1]monitoring of changes indicative of early stage melanoma.11 Studies have shown improved specificity for melanoma diagnosis and a 3.3 fold reduction in unnecessary biopsies with the use of sequential digital dermoscopic imaging.12 Furthermore most melanomas diagnosed using digital photography and dermoscopy are either in situ or minimally invasive (<1mm).7

The new FotoFinder technology (FotoFinder Systems GmbH, Bad Birnbach, Germany), now available locally at Saint James Burmarrad, combines TBP and dermoscopy. It creates high resolution total body photographs in a standardised manner, thus capturing all the patients’ moles for baseline referencing. This will be used as an adjunct to total body skin examination, by a dermatologist, at subsequent visits. The patient will also receive these images as a reference to aid self-skin examination. Furthermore FotoFinder records digital dermoscopic images of concerning moles thus allowing for serial close follow-ups with the aim of identifying melanomas as early as possible.

The following patients should be considered for referral to a dermatologist for consideration of FotoFinder:

  1. Personal history of malignant melanoma
  2. Patients with multiple (atypical) naevi
  3. Patients with a first-degree relative who has had melanoma
  4. Patients with a significant history of sun exposure (in particular occupational sun exposure)
  5. Patients with fair skin types (unable to tan).

References are available online.