Incidence of Melanoma and Non-melanoma Skin Cancer in People With Vitiligo

Study Overview
=================
Brief Summary
-----------------
This study examines melanoma and nonmelanoma skin cancer in people diagnosed with vitiligo compared to matched controls.

Detailed Description
-----------------
For the primary analysis, this study examines the risk of melanoma and nonmelanoma skin cancers: squamous cell carcinoma and basal cell carcinoma in people diagnosed with vitiligo. It also examines actinic keratoses. In secondary analysis, this study examines the prevalence of skin cancer in people diagnosed with vitiligo compared to matched controls. This study also examines whether the susceptibility to melanoma and nonmelanoma skin cancer may vary between different patient subgroups, e.g. ethnicity, those who undergo phototherapy or treatment with the new targeted biologic immunosuppressive therapies.

Official Title
-----------------
Incidence of Melanoma and Non-melanoma Skin Cancer in People With Vitiligo: A Case-control Study in the United Kingdom, 2009-2020

Conditions
-----------------
Vitiligo, Melanoma (Skin), Nonmelanoma Skin Cancer, Squamous Cell Carcinoma, Basal Cell Carcinoma, Actinic Keratoses

Intervention / Treatment
-----------------
* Other: Exposure of skin cancer of interest


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: All eligible adult patients (aged ≥ 18) registered with General Practioner (GP) practices contributing data to OPCRD between January 1, 2010 and December 31, 2020, were eligible for inclusion in the study. People diagnosed with vitiligo prior to the study period (prevalent vitiligo) and people newly diagnosed with vitiligo during the study period (incident vitiligo) are included as cases. Exclusion Criteria: People actively registered with the GP practice at that date without a history of vitiligo require a minimum one-year registration with their GP practice.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Cases<br>Patients with a confirmed diagnosis of Vitiligo within the study period will be included as cases for analysis. | Other: Exposure of skin cancer of interest<br>* Melanoma and nonmelanoma skin cancers: squamous cell carcinoma, basal cell carcinoma and actinic keratoses.<br>|
| Controls<br>The controls will be defined by matching cases with people who have never been diagnosed with vitiligo either prior to or during the study period, by age and sex, at General Practice level. | Other: Exposure of skin cancer of interest<br>* Melanoma and nonmelanoma skin cancers: squamous cell carcinoma, basal cell carcinoma and actinic keratoses.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Risk of new onset skin cancer in adult people diagnosed with vitiligo | Risk of new onset skin cancer assessed prospectively in vitiligo cases and matched controls. The skin cancer outcome comprises of the composite of melanoma and nonmelanoma skin cancers: squamous cell carcinoma and basal cell carcinoma. | 10 years from the index date | 
| Risk of new onset skin cancer in adult people diagnosed with vitiligo by sociodemographic subgroups | Risk of new onset skin cancer assessed prospectively in vitiligo cases and matched controls. Sociodemographic subgroups defined by age, sex, socioeconomic status and ethnicity. | 10 years from the index date | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Prevalence of skin cancer in adult people diagnosed with vitiligo | Skin cancer is defined as the composite of melanoma and nonmelanoma skin cancers: squamous cell carcinoma and basal cell carcinoma. | At index date | 
| Prevalence of individual skin cancers in adult people diagnosed with vitiligo | Melanoma and nonmelanoma skin cancers: squamous cell carcinoma and basal cell carcinoma, and actinic keratoses. | At index date. |