More and more melanoma
There is a debate — like for many cancers — about whether much or all of the increase in melanoma rates reflects increases in ‘real melanomas’ or changes in diagnostic habits. I do not think the evidence is robust enough to decide absolutely. I wrote something in the BMJ many years ago on this topic and, to a large extent, what has happened since has not changed my views too dramatically. I think there is a bit of both going on.
A recent paper by Mistry and colleagues in the British Journal of Cancer (open access) makes interesting reading if you deliver health care however. The authors have attempted to model what will happen to cancer rates for the common cancers over the next 20 years or so in the UK. Predicted changes will include changes in incidence and changes due to demographic shifts. For melanoma, the number of cases is expected to double by 2030: half of this increase is due to predicted changes in age specific incidence and half due to demographic change. By 2030 melanoma will account for almost 5% of all male cancers, and be the fourth most common cancer in men.
Of course the prognosis for melanoma is very good compared with most other cancers (see the excellent CRUK pages for more on this), and perhaps this reflects that many of the lesions might be biologically fairly non-aggressive, or that we are better at diagnosing them early. The absolute numbers are sobering however: numbers of cases in men for the years 1984, 2007 and 2030 are 987, 5010, 10939. The changes in females are similar. This is an astonishing change in caseload. The clinical problem is that to diagnose a single melanoma those of us in secondary care see between 10 and 30 patients who are referred from primary care. So, from a narrow service perspective, the increase between now and then is not 10,000 (5000 each for men and women) but 10,000 times 20 = 200,000 visits. At present overall, there are around 500,000 referrals from primary care to secondary care for all skin patients.
Melanoma is not the end of the issue however. Other types of skin cancer such as basal cell carcinoma and squamous cell carcinoma are much more common, but the number of patients you ‘screen’ to find a single case is smaller than for melanoma. Nonetheless, my guess is that just like for melanoma we will see a doubling of caseload. We need to think hard about how this is all going to be handled.