Epidemiology
- Incidence of melanoma is doubling every 10 years
- 40 per 100,000/ year in Queensland, Australia
- 4 per 100,000/ year in Scotland
- Overall 1000 deaths / year in United Kingdom
- Education increasing the number of thin tumours detected
- Number of thick tumours detected annually remains constant
Risk factors
- Giant melanocytic naevus
- Total number of naevi
- Dysplastic naevus syndrome
- History of recurrent sunburn
- 10% autosomal dominant with reduced penetrance
Clinical features
Major Sign
- Change in size
- Change in shape
- Change in colour
- Diameter more than 7 mm
Minor signs
- Inflammation
- Bleeding
- Sensory changes
Early detection
- Lesion unlikely to be a melanoma without at least one major sign
- Educational efforts at early detection are proving successful
- Need to assess
- A = Asymmetry
- B = Border irregularity
- C = Colour variegation
- D = Diameter
Pathology
- 60% arise in pre-existing naevi
- Have initial radial and then vertical growth phase
- Determines growth characteristics of the tumour
Superficial spreading melanoma (65%)
- Occurs in middle age
- Female : male ratio 2:1
- Commonest sites - lower leg in women and trunk in men
- Usually slightly elevated lesion with variable colour
Nodular melanoma (27%)
- Aggressive tumour
- Occurs in younger age group
- Female : male ratio 1:2
- Early vertical growth phase
- Usually uniform colour, early ulceration and bleeding
Lentigo maligna melanoma (7%)
- Least malignant
- Usually found on face of elderly
- Long radial growth phase
- Presents as flat light brown macule
Acral lentiginous melanoma (1%)
- Aggressive tumour
- Commonest type found in negros and orientals
- Occurs on soles of feet and palms of hand
- Subungual melanomas included in this group
Intransit metastases
- Uncommon. Seen in <2% tumours
- Appear as intracutaneous metastases or 'satellites'
- Those within 2 cm of primary classified as part of it
- Usually associated with regional lymphadenopathy
Lymph node metastases
- Commonest metastatic presentation
- Reduces survival by 50%
- 70 - 80% patients with regional lymphadenopathy have distant disease
Tumour thickness
- Tumour thickness most important prognostic factor for local, distant
recurrence and survival
- Five year survival related to Breslow thickness:
- <0.75 mm = 95-99%
- 0.76-1.49 mm = 80-90%
- 1.5-3.99 mm = 60-75%
- >4.0 mm = <50%
- With regional lymphadenopathy 10-year survival is less than 10%
- No internationally agreed classification of definition of thin,
intermediate and thick tumours
- Review of trials and comparison of trials difficult
Melanoma surgery
Resection margins
- Until recently history rather than controlled trials have dictated
practice
- Handley (1907)
- Hunterian Lecture based on one case.
- Recommended 5 cm margin
- Butterworth and Klaude (1934)
- Found microscopic lymphatic invasion to 3 cm
- Recommended 5 cm resection margins
- Olson (1966)
- Trial of resection 1 cm vs. 3 cm resection margins
- Identical local recurrence rate but still recommended 5 cm margin
!
- WHO Melanoma Group (1990)
- Randomised controlled trial of 1 cm vs. 3 cm resection margins
- Resection margins did not influence survival
- Generally accepted resection margins based on clinical appearance
are:
- Impalpable lesions - 1 cm
margin
- Palpable lesion - 2 cm margin
- Nodular lesion - 3 cm margin
Regional lymphadenectomy
- 20% clinically palpable nodes are histologically negative
- 20% palpably normal nodes have occult metastases
- Therapeutic lymph node dissection provides regional control and
prognostic information
- No improvement in survival
- For tumours <0.75 mm thick - 90% cured by local excision alone
- For tumours >4.0 mm thick - 70% have distant metastases at
presentation
- For these two groups lymphadenectomy provides no added survival
benefit
- Lymphadenectomy for 'intermediate' thickness tumours controversial
Morbidity of lymphadenectomy
- Lymphoedema (26%)
- Seroma (
23%)
- 'Functional deficit' (8%)
- Wound Infection (5%)
- Persistent pain (5%)
Adjuvant Therapy
- Patients at high risk of recurrence should be considered for
systemic adjuvant therapy
- Patients include those with:
- Primary tumour > 4 mm thick
- Resectable positive locoregional lymph nodes
- No standard adjuvant therapy exists
- Interferon
a2b has shown promising results
- Shown to increase disease-free and overall survival
Isolated limb perfusion
- Intra-arterial chemotherapy
- Commonly used agents - melphalan +/- TNF-alpha
- Used with hyperoxygenation
- Hyperthermia with a temperature of 41-42
°C
- Perfusion generally last about 1 hour
- Usually combined with lymphadenectomy
Indications
- Intransit metastases
- Irresectable local recurrence
- Adjuvant therapy for poor prognosis tumours
- Palliation to maintain limb function
Morbidity of isolated limb perfusion
- Mortality (2%)
- Limb oedema (76%)
- Persistent pain (
60%)
- Neuropathy (25%)
- Venous thrombosis (10%)
- Septicaemia & thrombocytopenia (3%)
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