Melanoma

Melanoma is the most serious skin cancer and can be lethal with delayed diagnosis and advanced disease. With early detection simple surgical excision with wide margins can be enough and all that is necessary as well as ongoing surveillance.

There is wide variation to the appearance of a melanoma and melanomas can be coal black, red, blue, white and even salmon pink or amelanotic. Fortunately only 2% of melanomas are amelanotic as these can lead to delays in diagnosis because of sometimes false reassurance. All are dangerous and potentially lethal.

The following criteria are commonly accepted as hallmarks of a suspicious lesion, the so called ABCs of melanoma.

  • Asymmetry or odd shape, not a perfect circle
  • Border irregularity
  • Colour irregularity within a lesion
  • Diameter, 5mm or larger
  • Evolution, that is growing or increasing in size

Any skin lesion including mole or pigmented patch that has changed in colour, size, shape or become irritated should be regarded as suspicious and considered for biopsy or complete excision for accurate histopathological or tissue diagnosis.

Melanomas can occur anyway on the surface of the body even hidden in odd locations including non sun-exposed anatomical area such under toe or fingernails and in the white zone covered by underwear. Do not assume that the skin has to be sun-tanned to have a melanoma. Of course sun-tanned skin zones are more likely to have a melanoma than non sun-exposed anatomical locations but melanomas can occur in these non-sunned exposed zones of the body.

In men the commonest sites for melanomas are on the torso or trunk front and back, particularly the back and in women the commonest sites are the legs on both sides, front & back. These areas of course require a higher degree of surveillance but the same rule applies. Any change in a skin lesion in size, shape, colour or border should be regarded as suspicious and a biopsy or excision should be considered.

There are four main types of melanomas:

  • Superficial spreading melanoma
  • Nodular melanoma
  • Lentigo maligna melanoma
  • Acral melanoma

Superficial spreading melanoma is the commonest type accounting for approximately 75% of all melanomas with nodular melanoma accounting for 15% and lentigo maligna melanoma accounting for approximately 5-10% with the least common type being acral melanoma which affects the hands and feet.

Management of melanoma involves:

  • History and examination
  • Diagnostic excision
  • Discussion about the pathology report
  • CT/PET staging
  • Wide local excision, either under local anaesthetic or as a day surgical in-hospital procedure requiring simple but large excision, excision with skin flaps or skin grafting to close the defect created by the excision.
  • Sentinel node biopsy if melanoma >1mm thick or adverse features
  • Completion lymphadenectomy of axilla or groin or removal of lymph nodes from the armpit and groin
  • Radiotherapy if indicated
  • Referral to a cancer care centre such as Peter MacCallum Cancer Centre for special care if required for advanced melanoma, such as neurosurgery for brain metastases or thoracic surgery for lung metastases and also for inclusion in melanoma clinical therapy trials.

After excision and appropriate treatment of a melanoma follow-up needs to the undertaken for the detection of local recurrence or to detect regional recurrence of melanoma in draining lymph node basins, usually in the groin and axilla. Imaging may need to be done at the same time and also needle sampling or cytology of any lump for cellular diagnosis.

Interval surveillance is usually conducted on a lengthening schedule at 1 week, 1 month, 6 months, 1 year and on a yearly basis thereafter for 5 years.

Having had one melanoma puts a patient at an increased risk of having another melanoma or non-melanoma skin cancer and close surveillance needs to be undertaken and not allowed to lapse.

Computer generated recall and reminders are issued from Fitzpatrick House and the Gippsland Melanoma and Skin Cancer Clinic at specified intervals after each appointment. SMS appointment reminders can be issued to a patient’s mobile phone number the day prior to an appointment.