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 % | |
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 |