In a new study published in the British Journal of Ophthalmology, researchers said there has been a steady rise in the incidence of squamous cell carcinoma (SCC) of the eyelid in England since 2000. They believe that behavioral changes and medical advances may underlie the increase.

The researchers examined more than 4000 cases of primary eyelid cancer diagnosed over a 14-year period. They found that the incidence of the disease, which can cause disfigurement and, occasionally, death, has increased by around 2% per year. The study also showed that the risk for eyelid SCC doubles with every decade in individuals aged over 60 years and that men are almost twice as at risk as women.

The researchers show that the epidemiology of eyelid SCC has strong similarities with SCC of the skin and with eyelid BCC [basal cell carcinoma] but less so with cutaneous melanoma. Although the incidence of overall SCC has increased over the past 20 years, and there is an association between SCC incidence and male sex, age, sun exposure, and higher socioeconomic status, there are no recent data on the incidence and associated factors for eyelid SCC.

The researchers, therefore, examined data from the UK National Cancer Registration and Analysis Service to identify all cases of incident primary eyelid SCC in England diagnosed between 2000 and 2014. Over the study period, 4022 patients were diagnosed with primary SCC of the eyelid in England. The team calculated that age-standardized incidence rate (ASR) gradually rose, at a Spearman's rank order correlation coefficient of 0.952.

This equated, on linear regression, to an increase of 0.0137 cases per 100,000 populations per year, or a rise in SCC risk of approximately 2% per year. Men were calculated to be 1.9 times more likely to be diagnosed with eyelid SCC, and this remained stable over the study period. Age was exponentially correlated with incidence, with the risk approximately doubling every decade over 60 years of age.

The association between eyelid SCC and age is likely due to cumulative exposure to environmental risk factors including UV radiation and iatrogenic causes such the use of systemic immunosuppression to treat autoimmune disease and prevent rejection of solid organ transplants. The increased UV exposure in men may play a role, although intrinsic factors, such as the protective effect of estrogen on keratinocytes, may also be involved.

The researchers continue alternatively, the behavioural factors relevant to cutaneous melanoma incidence may simply be different to those relevant to SCC of the eyelids, as demonstrated by the strong association between higher socioeconomic status and cutaneous melanoma while this effect was found to be weaker for non-melanoma skin cancer and in the present study to be completely absent for eyelid SCC.