Psoriasis is a chronic skin condition that is typically characterised by raised plaques with silvery scales on the skin. Beyond these direct symptoms, the condition is also associated with a number of other conditions, such as heart disease and depression. A less well understood association is that between psoriasis and cancer.
In examining a possible link between psoriasis and risk of cancer, it is important to consider the presence of additional risk factors. Perhaps the most noteworthy of these factors is the role of psoriasis severity, with some earlier studies suggesting that risk of experiencing some cancers may differ according to severity of psoriasis. Furthermore, it is also possible that other cancer risk factors such as smoking, higher levels of alcohol consumption, obesity and certain treatments are also involved in any increased risk.
The aim of this study is therefore to explore the association between psoriasis and cancer, with a particular consideration for psoriasis severity and the influence of potential cancer risk factors.
The association between psoriasis and cancer remains unclear, with regards to both overall cancer and specific cancers. The aim of this study is therefore to explore whether individuals with psoriasis are at an increased risk of developing cancer, and dying due to cancer, compared to the general population.
In order to achieve these aims, retrospective matched cohort studies will be conducted using both CPRD GOLD and CPRD Aurum. Psoriasis patients will be extracted using a Read code diagnosis of psoriasis from within the health record. Psoriasis patients with linkage to HES, ONS and IMD records and placement in a practice with at least 12 months up to standard practice registration will be matched to 6 psoriasis-free comparison patients by sex, age and general practice. For psoriasis cases, follow-up will begin at the date of first psoriasis record after 1 year of registration in an up to standard practice. For controls, follow-up will begin at the same date as the psoriasis patientÂ’s index date. For both cases and comparison patients, follow up will end at the first to occur of; first cancer diagnosis (primary outcome 1), cancer death (primary outcome 2), death from any cause other than cancer, transfer out of the practice, last date of data collection or the end of the study period. Cancer outcomes of interest will be identified using both Read and ICD-10 codes. Cox proportional hazard models will be used to examine the risk of cancer and cancer mortality in patients with psoriasis compared to those without psoriasis. The analyses will examine the impact of other risk factors including psoriasis severity, smoking status, alcohol consumption and BMI.
Cancer incidence recorded in primary or secondary care; Cancer mortality; negative control outcomes (hernia operation; glaucoma operations).
Specific cancers of interest are the 20 most commonly diagnosed within the UK, with the addition of cancers previously suggested to be associated with psoriasis, smoking, alcohol consumption or obesity: bladder, brain/CNS, breast, cervical, colorectal, endometrial, gallbladder, Hodgkin lymphoma, keratinocyte, kidney, laryngeal, leukaemia, liver, lung, malignant melanoma, multiple myeloma, nasal cavity, non-Hodgkin lymphoma, oesophageal, oral cavity, ovarian, pancreatic, pharyngeal, prostate, stomach, thyroid and uterine.
Darren Ashcroft - Chief Investigator - University of Manchester
Alex Trafford - Corresponding Applicant - University of Manchester
Christopher Griffiths - Collaborator - University of Manchester
Evangelos Kontopantelis - Collaborator - University of Manchester
Rosa Parisi - Collaborator - University of Manchester
Tjeerd van Staa - Collaborator - University of Manchester
HES Admitted Patient Care;HES Outpatient;ONS Death Registration Data;Patient Level Index of Multiple Deprivation