Incidence of Nonmelanoma Skin Cancers in Alberta, Canada, From 2007 to 2018

Background: Nonmelanoma skin cancer (NMSC) is the most common malignancy affecting Caucasian populations and has been seeing steady increases in incidence globally for decades. Our previous study (from Alberta, Canada) had shown a plateau in the incidence rates for NMSC. This contrasts with data from other regions within Canada and throughout the world that indicated a continued increase in incidence rates of NMSCs. Objectives: The objective of this study was to provide an update on the trends in incidence of NMSC in Alberta, Canada, from 2007 to 2018. Methods: A retrospective analysis of patients from Alberta diagnosed with NMSC from 2007 to 2018 inclusive was conducted with data retrieved from Alberta Cancer Registry. Sex-, age-, anatomical location-, NMSC subtype-, stage-specific incidence rates and trends were examined. Results: From 2007 to 2018, overall incidence rates of NMSC increased by 36%. Invasive squamous cell carcinoma (SCC) and in situ SCC demonstrated the most significant increase, invasive SCC [annual percentage change (APC) 3.48, P = .014] and in situ SCC (APC 5.61, P = .0001). In addition, we were able to determine that females had the most significant increases in NMSC incidence rates from 2007 to 2018 particularly invasive SCC (APC 3.03, P = <.0001) and in situ SCC (APC 5.08, P = <.0001). Conclusions: After initial levelling of NMSC incidence in Alberta in the early part of 21st century, the incidence of NMSC continues to increase over the past decade. The reasons for this change are not clear and likely multifactorial.