Malignant Neoplasm of Skin

Melanoma and non-melanoma skin cancers are the most common types of skin cancer, with non-melanoma skin cancers being more prevalent but less deadly than melanoma.

Diagnosis

Melanoma:

  • Clinical Evaluation:
    • The first step is usually the visual inspection of the skin.
    • We use the ABCDE rule to evaluate moles or growths on the skin:
      • Asymmetry: One half of the mole doesn’t match the other.
      • Border: Edges are irregular, ragged, notched, or blurred.
      • Color: The color is not the same all over and may include shades of brown or black, sometimes with patches of pink, red, white, or blue.
      • Diameter: The spot is larger than 6 millimeters across although melanomas can sometimes be smaller than this.
      • Evolving: The mole is changing in size, shape, or color.
    • Dermoscopy: A dermatoscope is used to examine suspicious lesions more closely.
  • Biopsy:
    • Any suspicious lesion should be biopsied
    • The NHMRC recommend excision biopsy with 2 mm margins whenever possible.
    • An incision, punch or shave biopsy from the most suspicious area of a large pigmented lesion may be appropriate when complete excision would be difficult.

Non-Melanoma Skin Cancer (BCC and SCC)

  • Clinical Evaluation: Non-melanoma cancers are Basal Cell Carcinoma (BCC) and Squamous Cell Carcinoma. They present as a change in the skin, such as a growth, a sore that doesn’t heal, or a change in an existing skin lesion.
  • Biopsy:
    • An exision, punch or shave biopsy is performed to diagnose non-melanoma skin cancer definitively.
    • Misdiagnosis is possible with incomplete biopsies ie punch (which may miss the cancerous cells) or shave (which may not be deep enough to see the cancerous cells).
    • For excision biopsy margins of 2mm are suggested.

Management

The management of skin cancers depends on the type, stage, and location of the cancer, as well as the patient’s overall health.

Melanoma

  • Surgical Removal:
    • The primary treatment for melanoma is surgical removal of the tumor with an appropriate margin of normal skin
      • The initial excision biopsy margin should be 2mm and down to subcutaneous fat
    • Melanoma wide excision margins (after initial excision biopsy) recommended in the Clinical Practice Guidelines for the Management of Cutaneous Melanoma in Australia and New Zealand
    • Breslow thickness* Surgical margin Melanoma in situ 5 mm Melanoma <1.0 mm 1 cm Melanoma 1.0–4.0 mm 1–2 cm* Melanoma >4.0 mm 2 cm  * For melanomas 2–4 mm thick, it may be desirable to take a 2 cm margin where possible
    • Note that re-excision is required for all melanomas diagnosed with a 2mm margin excision biopsy as the minimum margin is 5mm
  • Sentinel Node Biopsy: For melanomas of intermediate thickness, sentinel node biopsy may be considered to evaluate the spread to nearby lymph nodes, particularly for melanomas > 1mm in thickness
  • Staging: CT or PET are NOT recommended unless Stage 3 (metastatic disease)
  • Further Treatment: Additional treatments after surgery might include immunotherapy, targeted therapy, chemotherapy, or radiation therapy.
  • Follow-up: Regular follow-up visits are crucial for monitoring recurrence.


Non-Melanoma:

  • Surgical Excision: Small, localized cancers can often be completely removed with excisional surgery.
  • Mohs Surgery: This precise technique is especially useful for cancers that have a high risk of recurrence or are in areas where it’s important to preserve as much healthy tissue as possible ie nasal BCCs
  • Cryotherapy: For small lesions, especially in older patients, freezing the cancer cells with liquid nitrogen may be an option.
  • Topical Treatments: Some very superficial BCCs or SCCs may be treated with topical chemotherapy (5-Fluorouracil) or immune response modifiers (Imiquimod).
  • Radiation Therapy: This may be used where surgery isn’t an option, or to improve cosmetic outcomes for lesions on the face.
  • Photodynamic Therapy (PDT): PDT uses a combination of laser light and a drug that makes cancer cells sensitive to light.
  • Electrodesiccation and Curettage (ED&C): This method involves scraping the tumor away and using electricity to kill any remaining cancer cells.
  • Follow-up: Regular skin checks are important to catch any new or recurrent skin cancers early.

Prevention and Education

For both melanoma and non-melanoma skin cancers, prevention and patient education are key. Patients should be advised to:

  1. Avoid excessive sun exposure, especially during peak hours.
  2. Use broad-spectrum sunscreen with an SPF of at least 30.
  3. Wear protective clothing, sunglasses, and hats when outdoors.
  4. Avoid tanning beds.
  5. Perform regular self-examinations of their skin for new growths or changes in existing moles.
  6. Attend regular skin checks with a healthcare professional.

Early detection of skin cancer, particularly melanoma, is vital because it significantly improves the chances of successful treatment.