Doctors Revision

Oncology

Melanoma

A malignant tumour arising from melanocytes, the pigment-producing cells primarily found in the skin. Can also occur in eyes, mucous membranes. Less common than other skin cancers but more dangerous due to potential for metastasis.

Also known as: Malignant Melanoma, Skin Cancer (Melanoma)

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Referral and warning signs

When to refer

Urgent referral to Dermatologist/Surgeon for biopsy of ANY suspicious pigmented lesion (ABCDE criteria, changing/symptomatic mole). Refer confirmed melanoma cases to oncology/surgical oncology centre for staging and management.

Red flags

  • Pigmented lesion meeting ABCDE criteria
  • Changing mole (size, shape, colour)
  • New mole appearing after age 40-50
  • Bleeding, itching, or ulcerated mole
  • Pigmented lesion growing rapidly

Signs and symptoms

  • Appearance of a new mole or pigmented lesion.
  • Change in an existing mole - Use ABCDE criteria: A: Asymmetry, B: Border irregularity, C: Colour variegation, D: Diameter >6 mm, E: Evolving (size, shape, colour, elevation, symptoms like itching/bleeding/crusting).
  • Ulceration or bleeding of a pigmented lesion.
  • Development of satellite lesions or in-transit metastases (pigmented spots/nodules near primary).
  • Palpable regional lymph nodes.

Risk factors

  • Excessive UV radiation exposure (sunlight, tanning beds), especially intermittent intense exposure leading to sunburn.
  • Fair skin type (easily burns, rarely tans).
  • Multiple moles (nevi), especially atypical/dysplastic nevi.
  • Personal history of melanoma or other skin cancers.
  • Family history of melanoma.
  • Immunosuppression.
  • Certain genetic mutations (e.g., CDKN2A).

Diagnosis

Clinical assessment

Suspect based on clinical appearance of pigmented lesion using ABCDE criteria or any changing/symptomatic mole. Requires high index of suspicion.

Investigations

  • Dermoscopy: Examination with a magnifying tool with special lighting can help differentiate benign from suspicious lesions (requires training).
  • Excisional Biopsy: Gold standard for diagnosis. Entire suspicious lesion should be excised with narrow margins (1-3mm) down to subcutaneous fat. Allows for accurate histological assessment and measurement of Breslow thickness (tumour depth - crucial prognostic factor). Shave/punch biopsy generally discouraged unless lesion very large.
  • Histopathology: Confirms melanoma diagnosis, determines subtype, Breslow thickness, ulceration status, mitotic rate.
  • Sentinel Lymph Node Biopsy (SLNB): Considered for melanomas >0.8-1mm thick (or thinner if ulcerated/high mitotic rate) to assess for microscopic nodal metastasis (staging/prognostic).
  • Staging Investigations (for thicker/node-positive/symptomatic disease): Imaging (CT, PET-CT), LDH blood test.

Diagnostic criteria

Histopathological confirmation from biopsy.

Management

Non-pharmacological management

  • Referral to specialist (Dermatologist/Surgical Oncologist/Oncologist).
  • Surgical Excision: Wide Local Excision (WLE) with wider margins (1-2cm) after diagnosis confirmed. Sentinel Lymph Node Biopsy (SLNB) as indicated. Completion Lymph Node Dissection (CLND) if SLNB positive (role debated now). Surgery for metastatic disease (selected cases).

Pharmacological treatment

  • Adjuvant Therapy (Stage IIB/IIC/III): Immunotherapy (PD-1 inhibitors - Pembrolizumab/Nivolumab) OR Targeted Therapy (BRAF + MEK inhibitors if BRAF V600 mutated).
  • Treatment for Metastatic (Stage IV) Melanoma: Immunotherapy (PD-1 inhibitors +/- CTLA-4 inhibitors - Ipilimumab) OR Targeted Therapy (BRAF/MEK inhibitors) if BRAF mutated. Chemotherapy (limited efficacy).

Monitoring

Regular skin self-examination and clinical skin checks. Monitor regional lymph nodes. Follow-up imaging as indicated for high-risk/metastatic disease. Monitor for treatment side effects.

Complications

  • Local recurrence
  • In-transit / Satellite metastases
  • Lymph node metastases
  • Distant metastases (lung, liver, brain, bone, skin)
  • Side effects of immunotherapy/targeted therapy/chemotherapy
  • Complications of surgery (scarring, lymphoedema)

Prevention

  • Sun Protection: Avoid peak sun hours, seek shade, wear protective clothing, use broad-spectrum sunscreen (SPF 30+).
  • Avoid tanning beds.
  • Regular skin self-examination.
  • Clinical skin checks for high-risk individuals.

Patient education

  • Explain melanoma diagnosis and importance of Breslow thickness/staging.
  • Sun protection measures.
  • How to perform skin self-examination.
  • Importance of regular clinical follow-up.
  • Treatment options.
  • Signs of recurrence or new suspicious lesions to report.

Uganda-specific notes

While less common overall than in fair-skinned populations, melanoma occurs, including acral lentiginous melanoma (palms, soles, under nails) which is more common in darker skin types. Persons with Albinism are at extremely high risk. Awareness and sun protection crucial for this group. Access to specialist care, biopsy interpretation, SLNB, and modern systemic therapies (immuno/targeted) is very limited.

References

  • Uganda Clinical Guidelines (UCG) 2023

    Chapter 12, Section 12.3.2 (Listed under Adult Cancers)

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