Newton-Bishop and Lorigan have raised important questions about the role of technology in improving patient outcomes (1). Technology seduces patients and providers, yet again is lacking an evidence base. Responses to this article reveal the tensions between a rising skin cancer incidence, increasing patient awareness, and appropriate referral amidst austerity measures. The spotlight is squarely focused on primary care.

However, little data is published on secondary care diagnostic performance. Whilst the profile of referrals to secondary care would ideally reflect a higher specificity and sensitivity of pickup in primary care, dermatologists have largely not declared their diagnostic performance when processing these referrals. This could be easily done through a declaration of surgical histology results. Are dermatologists sifting referrals to distinguish the good from the bad and the plain ugly? Are they providing PCTs and future commissioning groups with a good value surgical service?

Part of the problem lies in poor existing measures of diagnostic performance. The most widely used indices, the benign:malignant ratio (the number of benign naevi divided by the total number of melanomas) and the number needed to treat (number of melanocytic lesions excised for each melanoma), are weak surrogate markers of specificity at best (2). Neither reflects detection of thin melanoma which, although harder to diagnose, carries a better prognosis if excised, and is a surrogate for diagnostic sensitivity.

The time is ripe for General Practice to put the pressure on secondary care departments to be more transparent about their diagnostic performance and surgical services. Part of this will necessitate validated and acceptable measures of performance that will demonstrate that dermatologists can distinguish melanoma from benign lesions, and excise early melanoma. Such data is beginning to emerge (3), however commissioning groups will need to press harder for answers.

References:

1. Newton-Bishop J, Lorigan P. Identifying melanomas in primary care: can we do
better? BMJ [Internet]. 2012 Jul 4 [cited 2012 Sep 9];345(jul04 1):e4244–e4244.

2. Chia ALK, Simonova G, Dutta B, Lim A, Shumack S. Melanoma diagnosis:
Australian dermatologists’ number needed to treat. The Australasian journal of
dermatology [Internet]. 2008 Feb [cited 2012 Sep 9];49(1):12–5.

3. Sidhu S, Bodger O, Williams N et al. The number of benign moles excised for
each malignant melanoma: the number needed to treat. Clin Exp Dermatol
2012 Jan;37(1):6-9

Competing interests: None declared