Epidemiology

Of note in the epidemiology of malignant melanoma (MM):

• the incidence
  • has doubled every ten years in recent times
  • in Mediterranean countries it is 3-5/100,000/year while in Nordic countries it is 12-20/100,000 and is still rising (1)
  • this rapid increase in incidence is also seen in countries which historically had low incidence rates (2)
  • Australia has the highest incidence of MM worldwide (in western and northern Australia) e.g. in Queensland the cumulative incidence in people more than 50 years is 1 in 19 for men and 1 in 25 for women (2)
    
    
• it is rare among deeply pigmented ethnic groups in contrast to fair-skinned people of northern European - Celtic – origin (2).
  • incidence in this group has increased considerably over the last two decades
  • melanoma in the non white population is most likely to occur in acral locations such as the palmar or plantar surface or the nail bed (3)
  • noncutaneous melanomas (e.g.-mucosal) are commoner in non white races (2)
    
    
• very common disease in albinos
  
  
• incidence is non-linearly related to sun exposure - short intense periods of exposure are more common in melanotic patients. Cumulative sun exposure may be more relevant in lentigo malignant melanoma (MM)
  
  
• genetic predisposition to MM may also occur, with approximately 1-5% of patients with MM having a family history
  • rare high-risk genes occur that are inherited as autosomal dominants, and these may manifest as multiple primary tumours in an individual and/or clustering in families
  • in the general UK population, individuals with multiple moles (the atypical mole syndrome (AMS) also known as dysplastic naevus syndrome) are at increased risk of MM and this is thought to be genetic, probably due to low-penetrance susceptibility genes
    • phenotype is common and patients with the AMS require education about prevention, both primary (sun avoidance) and secondary (signs and symptoms)
    • patients with AMS have a relative risk of MM of around 10 compared with those who have very few moles (lifetime risk of MM in the UK is approximately 1 in 150; patients with AMS have an estimated 1 in 20 lifetime risk compared with a person with an average number of moles. Their risk is lower when compared, for example, with those with xeroderma pigmentosum, but as 2% of the general population have the AMS these patients 'explain' a significant proportion of the disease (1)

In UK:

• the lifetime risk for an individual developing the disease is 1:120 for men and 1:95 for women (2)
• around 8500 new cases and 1800 melanoma related deaths are reported annually (3)

Sex and age of onset:

• MM is more common in females than in males (4)
• in 2001 there were 6432 new cases of MM registered in England and Wales
  • age-standardised incidence of MM has been steadily increasing over the past three decades in both males and females with rates of 11.7 (females) and 10.1 (males) per 100,000 population by 2001 (4)
• MM is rare before puberty
  • the incidence increases steadily from the age of 15 years in both men and women and peaks at around the age of 50
  • around 80% of lesions are seen in people between the ages 20 -74 years (3)
    • the median age of diagnosis in men was 62 years while in women it was 60 years (4)
• age-specific mortality rates for MM of the skin are higher in men than in women in the older age groups, and the increase in mortality with age mirrors the increase in incidence (4)
  • male mortality rates from MM have risen steadily since 1970 and had more than doubled by 2001 (1.0/100,000 in 1970, 2.6/100,000 in 2001)
  • mortality in females increased across the same time period, but to a smaller extent (from 1.4/100,000 to 2.0/100,000 population)
• lower leg is the most common site in females but in males, the trunk is most affected. Other common sites are the head and neck

Reference:

• (1) Dummer R et al. Melanoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol. 2010;21 Suppl 5:v194-7
• (2) Markovic SN et al. Malignant melanoma in the 21st century, part 1: epidemiology, risk factors, screening, prevention, and diagnosis. Mayo Clin Proc. 2007;82(3):364-80
• (3) Bristow IR et al. Clinical guidelines for the recognition of melanoma of the foot and nail unit. J Foot Ankle Res. 2010;3:25
• (4) NICE (February 2006).CSG Improving Outcomes for People with Skin Tumours including Melanoma: The Manual