Nationwide study of cutaneous basal cell carcinoma incidence trends in Norway, 2012–2022

Abstract

Background Basal cell carcinoma (BCC) is the most common cancer in fair-skinned populations world-wide. However, population-based incidence is rarely reported as most countries do not register BCC. In Norway, melanoma and non-melanoma skin cancers (excluding BCC) are the cancers with the steepest incidence increase since 2000. However, the incidence of BCC remains unknown due to lack of registration. Objectives We aimed to utilize archived pathology reports in the Cancer Registry of Norway (CRN) to estimate the national BCC incidence. Methods The CRN receives pathology reports for all verified malignant diagnoses. Using those reports, we identified BCCs diagnosed in Norway 2012–2022 and estimated annual person-based (the first pathology report per person only) and tumour-based (first pathology report per person per year) incidence rates. We stratified by sex, age (0–49, 50–59, 60–69, 70–79 and 80+ years) and health regions (south-eastern, western, central and northern Norway). Changes over time were analysed using Poisson regression and expressed as the average annual percentage change (AAPC) with 95% confidence interval (CI). For validation, we estimated person-based melanoma incidence rates using pathology reports and compared with the officially published incidence rates. Results During 2012–2022, we identified 70,830 individuals (54.6% women) diagnosed with a first primary BCC (person-based), including 170,308 BCC diagnoses (tumour-based) (52.1% in women). The person-based incidence rate (per 100,000 person-years) increased from 106.8 to 213.3 in women and from 111.6 to 201.3 in men (AAPCs 6.2 (CI: 5.9–6.6) and 6.5 (CI: 6.1–6.8) respectively). Tumour-based rates increased from 242.5 to 421.9 in women (AAPC 4.9 (CI: 4.7–5.1) and from 284.8 to 436.5 in men (AAPC 4.5 (CI: 4.2–4.7)). Steepest increase was seen for ages <60 years and in the northern region. The estimated melanoma incidence rates, based on pathology reports, were higher than the officially published rates, but differences were small. Conclusion During 2012–2022, the BCC incidence almost doubled in Norway. Tumour-based incidence was nearly twofold the person-based, demonstrating that person-level incidence substantially underestimates the BCC burden on healthcare systems, patients, and society. This underscores the need for effective resource planning and prevention strategies.