Over the past two decades the number of new cases of skin cancer worldwide has risen substantially, increasing demand for healthcare. In the UK, the three commonest skin cancers are cutaneous melanoma (CM), basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). CM is less common but requires early recognition and treatment, otherwise 5-year survival rates can be as low as 45%. BCC and SCC are much commoner and seldom cause death, but can lead to disfigurement and recurrence.
We currently rely on cancer registries to estimate how common different cancers are; however, there is under-reporting of skin cancers in such registries, particularly SCC and BCC. A better understanding of the burden of common skin cancers across the UK and in primary care can inform policies and efforts to improve the management of skin cancer, e.g. ensuring enough resources are provided for GPs to care for such patients.
This study will use data from a general practice records database (CPRD) to study how frequently skin cancers are diagnosed, as well as studying whether rates of such cancers are increasing.
This work aims to quantify the burden of skin cancer in UK primary care and to inform system-level policies in skin cancer management. It aims to use primary care data from the Clinical Practice Research Datalink (CPRD) to study the epidemiology and primary health care burden of melanoma and non-melanoma skin cancers in a UK primary care population.
A retrospective cohort analysis will be conducted to estimate the age-adjusted incidence, prevalence, and all-cause mortality of the three commonest skin cancers - cutaneous melanoma (CM), squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) - over a ten-year timeframe (2004-2014).
Health Outcomes to be Measured:
The primary outcome will be:
Prevalence for the study end year (2014) will be determined by the presence of a skin cancer medcode (as defined by the appendix) in the patient's history. This is consistent with Cancer Research UK's definition of skin cancer prevalence as those who are living with or surviving cancer at a particular point in time24. The denominator will be the mid-year CPRD population in 2014.
Incidence will be defined as a first-ever MM, BCC, or SCC medcode in their file between January 1, 2004 and December 31, 2014 amongst patients with an active registration at any point between January 1, 2004 and December 31, 2014. Denominators for incidence will be obtained from year-specific CPRD denominator files. To avoid misclassifying a patient as an incident case when they are an ongoing case that has transferred into the CPRD cohort, only patients with at least one year of history in CPRD will be considered.
All-cause mortality will be calculated as the age-standardised mortality rate, using dates of death for patients who have died according to ONS data. All-cause mortality rate is defined as the number of deaths amongst patients with a history of a skin cancer diagnosis medcode.