The current burden of non-melanoma skin cancer attributable to ultraviolet radiation and related risk behaviours in Canada.

PURPOSE: Ultraviolet radiation (UVR) is an established cause of non-melanoma skin cancer (NMSC)-basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). The aim of this study was to estimate the current burden of BCC and SCC associated with UVR and modifiable UVR behaviours (sunburn, sunbathing, and indoor tanning) in Canada in 2015. METHODS: The current burden of BCC and SCC associated with UVR was estimated by comparing 2015 incidence rates with rates of less exposed body sites (trunk and lower limbs) after adjusting for estimated surface areas. The burden associated with modifiable UVR behaviours was estimated by using prevalence estimates among Caucasians from the Second National Sun Survey, and relative risks that are generalizable to Canadians from conducting meta-analyses of relevant studies. RESULTS: We estimated that 80.5% of BCCs and 83.0% of SCCs were attributable to UVR. Adult sunburn was associated with relative risks of 1.85 (95% CI 1.15-3.00) for BCC and 1.41 (95% CI 0.91-2.18) for SCC, while adult sunbathing was associated with relative risks of 1.82 (95% CI 1.52-2.17) for BCC and 1.14 (95% CI 0.53-2.46) for SCC. We estimated that 18.6% of BCCs and 9.9% of SCCs were attributable to adult sunburn, while 28.1% of BCCs were attributable to adult sunbathing. We estimated that 46.2% of BCCs and 17.3% of SCCs were attributable to modifiable UVR behaviours combined. CONCLUSION: Our results provide quantifiable estimates of the potentially avoidable burden of NMSCs among Canadians. These estimates can be used to motivate prevention efforts in Canada.