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Table 1 Estimated probabilities, sensitivity values and sources

From: Modelling the healthcare costs of skin cancer in South Africa

Probabilities Used in model Sensitivity valuesa Sources/assumptions
Melanoma    
 Proportion of cases of suspected melanoma are seen in public or private setting 20 %/80 % 15 %/85 %, 25 %/75 % Expert opinion, persons with white skin are more susceptible to skin cancers and seen in private settings
 Proportion of cases seen by GP who suspects a melanoma refers to a dermatologist or surgeon 80 % 70 %, 90 % Assumption based on convenience and high likelihood in public hospital to refer to specialist
 Proportion of suspected melanoma that were malignantb 80 % 75 %, 85 % Expert opinionc, Fong 2014 [12]
 Melanoma is surgically excised 100 % 87.9 % Expert opinion (all melanomas including advanced) Vallejo-Torres 2014 [10]
 Melanoma is greater than 1 mm thick 30 % 20 %, 40 % Expert opinionc
 Melanoma greater than 1 mm thick has metastasized 20 % 15 %, 25 % Expert opinionc
 Melanoma with no metastases is treated with interferon 2b alpha 3 % 2 %, 4 % Expert opinionc, Fong 2014 [12]
 Melanoma greater than 1 mm thick has metastases in lymph nodes 30 % 25 %, 35 % Expert opinionc, published literature - ranges from 4 to 44 %
 Melanoma with lymph node metastases is treated with radical LND 100 % Expert opinionc: All those with SLNB get RLND.
 Melanoma is treated by radiotherapy 5 % 4 %, 6 % Expert opinionc, most with metastases will only get palliative care, Fong 2014 [12]
 Melanoma is treated with chemotherapy 10 % 5 %, 7 % Expert opinionc, Fong 2014 [12]
Non-melanoma (NM)SCC or BCC    
 NM is treated by a GP in the public setting 100 % Expert opinionc, all seen first by a GP, (same for Aust. and England)
 NM case is referred to a dermatologist 60 % 50 %, 70 % Expert opinionc 60 % for dermatologist or surgeon
 Suspected NM is confirmed to be malignantc 85 % 80, 90 % Expert opinionc
 SCC is >2 cm diameter 10 % 8 %, 12 % Expert opinionc
 Large SCC is positive and surgeon treats by radical LND 20 % 15 %, 20 % Expert opinionc, Fong 2014 [12]
 NM is treated by:    
  Surgical excision 80 % 86.0 % Expert opinionc, Vallejo-Torres 2014 [10], Fong 2014 [12]
  Cryotherapy 10 % 3.1 % As above
  Curette and diathermy/electrodesiccation 5 % 7.5 % As above
  Topical cream 3 % 0.5 % As above
  Photodynamic therapy 1 % 0.8 % As above
  Radiotherapy 1 % 1.7 % As above
  1. LND lymph node dissection, GP general practitioner, SCC squamous cell carcinoma, BCC basal cell carcinoma
  2. aThe sensitivity values are the high and low estimates used in the sensitivity analysis. These are based on sources in the literature or judged as plausible ranges around the best estimate used in the model base case. For probabilistic sensitivity analyses, beta distributions were assigned to probabilities to account for uncertainty
  3. bExpert opinion is from practicing dermatologists and practicing doctors
  4. cLesions suspected of being Malignant are often investigated and later diagnosed as benign
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