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neo_skin

skin cancer

Introduction

  • 95% and 99% of skin cancers in Australia are caused by exposure to the sun
  • the average age at diagnosis for non-melanoma skin cancers in Australia is 76 years old

Basal cell carcinoma

  • 70% of non-melanoma skin cancers
  • begins in the lower layer of the epidermis
  • generally slow growing local spreading cancers which rarely metastasize
    • may be a pearly lump
    • may be a scaly, dry area that is shiny and pale or bright pink in colour
  • most commonly develops on parts of the body that receive high or intermittent sun exposure (head, face, neck, shoulders and back)
  • excisional Rx generally requires 3 to 5 mm margin of normal skin around the tumour
  • types:
    • Nodular BCC
      • these are the most common types and are the classic shiny pearly edged ones mainly on the face and may have central ulceration and blood vessels over the surface
    • Superficial BCC
      • in younger adults esp. on upper trunk and shoulders
      • slightly scaly, irregular plaque with multiple microerosions and thin, translucent rolled border
    • Morphoeic BCC
      • usually mid-facial
      • waxy, scar-like with indistinct borders
      • wide and deep subclinical extension and may infiltrate nerves
      • higher recurrence rates
      • usually managed best with Moh's surgery
    • Basosquamous carcinoma
      • mixed BCC/SCC with infiltrative growth and more aggressive behaviour

Cutaneous squamous cell carcinoma

  • less common than BCC accounting for 30% of non-melanoma skin cancers
  • begins in the upper layer of the epidermis
  • usually appears where the skin has had most exposure to the sun (head, neck, hands, forearms and lower legs)
  • generally grows quickly over weeks or months
  • suggestive features:
    • thickened red, scaly spot
    • rapidly growing lump
    • looks like a sore that has not healed
    • may be tender to touch

Keratinocyte dysplasias

  • includes solar keratoses, Bowenoid keratosis and squamous cell carcinoma in-situ (Bowen's disease)
  • may develop into non-melanoma skin cancers
  • rare for a solitary actinic keratosis to evolve to squamous cell carcinoma (SCC) 1)
  • the risk of SCC occurring at some stage in a patient with more than 10 actinic keratoses is thought to be about 10 to 15%
    • a tender, thickened, ulcerated, or enlarging actinic keratosis is suspicious of evolution to SCC
  • the number and severity of actinic keratoses can be reduced by taking nicotinamide (vitamin B3) 500 mg twice daily 2)

Merkel cell carcinoma

  • ~80 cases per year in Queensland
  • 5 year survival 41% (compared with 93% for melanoma)
  • related to UV exposure
neo_skin.txt · Last modified: 2023/06/24 11:42 by gary1

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