Johan Sieborg

Keratinocyte carcinoma (KC) places a considerable and growing burden on healthcare systems. Given the KC population’s heterogeneity, tailored clinical pathways are needed to accommodate diverse management needs. This study applied machine learning (ML)-based phenomapping to identify distinct real-world subgroups within a national KC population using demographic and medical history variables. The study included KC patients treated in publicly-funded, office-based dermatology practices and registered in the Danish Skin Cancer Registry (2014–2022). In 106,490 KC patients, 7 ML-derived clusters were identified. One cluster (22.2%; n=23,590) consisted primarily of young, well educated high-income medically noncomplex females presenting with low-risk basal cell carcinomas (BCCs). Four clusters (55.2%; n=58,736) comprised patients with a greater dermatological disease burden, characterized by facial BCCs, multiple BCCs, a greater proportion of squamous cell carcinomas (SCCs), a history of skin cancer or previous actinic keratosis-related treatment. The remaining 2 clusters (22.7%; n=24,164) comprised highly comorbid patients with a greater proportion of SCCs, a high number of KCs on the head and neck and high immunosuppressive drug exposure. ML-derived phenomapping of a national KC population identified distinct, clinically relevant KC subgroups, providing a basis for tailored clinical pathways with differentiated resource needs.

Despite the rising incidence of basal cell carcinoma (BCC), few studies have compared treatment outcomes or predicted recurrences using nationwide real-world datasets. Hence, the objective was to investigate and compare recurrence rates of nodular BCC (nBCC) and superficial BCC (sBCC) following treatment with standard excision (SE), curettage, cryotherapy, photodynamic therapy and imiquimod. Additionally, we identified predictors of BCC 2 year recurrence using machine-learning. The study examined BCCs treated in state-funded, office-based dermatology practices registered in the Danish Skin Cancer Registry from 2014 to 2024. A total of 131,119 tumours were included, comprising 100,221 nBCCs and 30,898 sBCCs. For nBCC, the lowest rate of recurrence was observed for SE, with an 8-year cumulative recurrence rate (CRR) of 16.5% (95% confidence interval: 14.4–19.0%) and hazard ratio of 0.80 (0.76–0.84) compared with curettage. For sBCC, both SE and curettage had similarly low 8 year CRRs of 16.3% (12.7–20.8%) and 16.3% (15.2 17.5%), respectively, with no significant difference in hazard. The machine-learning model identified key predictors of BCC recurrence, including facial location, larger tumour size, having a high number of hospital-registered diagnoses and short distance to dermatological clinics. These findings highlight the impact of treatment selection and patient-specific factors in guiding dermatologists towards optimal BCC management.

In this nationwide Danish cohort study, mild-to-moderate chronic hand eczema (CHE) was not associated with major adverse cardiovascular events (MACE). Severe CHE showed a marginally increased risk of MACE, including ischaemic stroke and mainly in hyperkeratotic and dyshidrotic subtypes, most likely reflecting residual confounding.

The incidence of basal cell carcinoma is increasing globally, with Denmark showing a 220% rise between 2013 and 2021, underscoring the need to optimize treatment strategies. Curettage with or without electrodesiccation (C±E) is commonly used, yet updated tumour-specific recurrence data are limited. Using the Danish Skin Cancer Registry, we assessed long-term recurrence after C±E for 47,358 basal cell carcinomas treated in office-based dermatological practices between 2013 and 2022. Follow-up began one year after treatment, and recurrence was evaluated using Kaplan–Meier analysis and Cox regression to estimate cumulative recurrence rates and hazard ratios (HR) by tumour characteristics. The 5-year recurrence rate was 9.9% (95% CI 9.4–10.3), increasing to 13.3% (12.6–14.1) at 8 years. Head and neck tumours had the highest recurrence (25.1% at 8 years; HR 2.25, 2.00–2.53), as did tumours >10 mm (16.7% at 8 years; HR 1.80, 1.62–1.99), while superficial basal cell carcinomas had the lowest recurrence (8.4% at 8 years; HR 0.46, 0.38–0.56). Incomplete follow-up may have introduced bias in recurrence estimates. This nationwide study, the largest to date with up to 8 years of follow-up, shows that C±E remains a viable treatment, but careful tumour selection is essential to optimize long-term outcomes.

Background: Many patients with melanoma experience worry, anxiety and distress. Screening for psychological distress can facilitate early identification and management. However, little is known about such distress in melanoma survivors and patients at high risk of developing melanoma. Objectives: The primary outcome was to assess the melanoma-related worry in melanoma survivors and patients at high risk of melanoma. Additionally, a secondary outcome was to determine the optimal Distress Thermometer (DT) cutoff for identifying those needing psycho-oncological support. Methods: We prospectively collected the distress-related patient-reported outcomes at the Department of Dermatology of the University Hospital in Basel, Switzerland between January 2021 and January 2024. Validated questionnaires including the DT, Melanoma Worry Scale, Patient Health Questionnaire, and Generalized Anxiety Disorder were used to assess the primary outcome. For the secondary outcome, receiver operating characteristic (ROC) analysis was used to estimate the optimal DT cutoff. Results: The study population comprised 430 individuals, including 175 (41%) melanoma survivors and 255 (59%) patients at high risk for melanoma. Worry about getting a primary or subsequent melanoma was more prominent in melanoma survivors (26%) compared with patients at high risk for melanoma (16%). Patients at high risk for melanoma had less melanoma worry compared with melanoma survivors, with an odds ratio (OR) of 0.56 [95% confidence interval (CI) 0.34–0.93]. Melanoma worry predictors included being divorced (OR 3.08, 95% CI 1.28–7.38) and younger age (OR 0.97, 95% CI 0.95–0.99). Patients at high risk of melanoma showed significant higher distress [median DT 4, interquartile range (IQR) 2–6] compared with melanoma survivors (DT 2, IQR 1–5) (P < 0.001). ROC analysis estimated a DT score of 3 as the optimal cutoff for melanoma survivors, whereas a DT score of 6 was optimal in patients at high risk of melanoma. Conclusions: This study found that melanoma survivors exhibit greater disease-specific worry, whereas patients at high risk for melanoma show increased general distress, underscoring their distinct psycho-oncological needs. Adopting tailored DT cutoffs (≥ 3 for melanoma survivors, ≥ 6 for patients at high risk for melanoma) may improve the detection of clinically relevant distress. Importantly, interest in psychological support was observed across all DT scores, indicating the need for flexible, patient-centred approaches. These findings highlight the unmet need for psychosocial care in both melanoma survivors and patients at high risk of melanoma, and could aid dermatologists in screening patients for psychological distress.

A mainstay treatment of head and neck basal cell carcinoma (BCC) is excision with a fixed surgical margin. Large-scale evaluation of post-surgical margin status is necessary to improve outcomes. This cross-sectional study assessed margin outcomes following excision of head and neck BCCs across Danish healthcare settings, including risk factors for tumour-positive margins. Histopathology records on BCCs excised by all medical specialities between 1 January–31 December 2022 were retrieved from The Danish Pathology Bank. Cases with intraoperative microscopic margin assessment were excluded. Descriptive analyses and multivariable logistic regression determined complete excision proportions and risk factors for positive margins. Including 9,291 BCC excisions in 7,741 patients, the tumour-free proportion was 80.0% (95% CI: 79.2–80.8%). Significant variation occurred by histologic subtype, with tumour-free margins ranging from 60.6% in morpheaform to 83.6% in nodular BCCs. Multivariable analyses also identified morpheaform, micronodular, infiltrating, and superficial subtypes, auricular/postauricular locations, small specimen size, and advancing age as risk factors for tumour-positive margins. The nose was a risk factor in univariable analysis. Simple excision of head and neck BCCs shows notable variation in margin outcomes by patient, tumour, and specimen profile. To minimise recurrence and optimise resources, increased awareness of positive margins is essential.

Background: Socioeconomic status (SES) and access to dermatological care are known to influence rates of keratinocyte carcinoma (KC). However, few studies have examined the impact of these factors on the disease burden of specific KC subtypes. Objectives: To determine the impact of SES and distance to a dermatologist on the burden of KC, determined by tumour incidence rate ratios (TIRRs) and tumour size, for nodular basal cell carcinoma (nBCC), superficial BCC (sBCC), squamous cell carcinoma (SCC) and the KC precursor, Bowen disease (BD). Methods: Using data from the nationwide Danish Skin Cancer Registry, our study included 100 705 patients with 190 468 histologically or clinically verified cases of KC/BD registered in state-funded office-based dermatology practices between 2013 and 2022. Negative binomial regression was used to calculate TIRRs; the impact on lateral tumour size was estimated with log-linear quantile regression. Results: High SES was associated with increased tumour incidence and smaller tumours for all KC subtypes. Rates of nBCC and sBCC were 2.7 times and 2.4 times higher, respectively, among the top 25% earners vs. the lowest income category [nBCC 2.74, 95% confidence interval (CI) 2.69–2.79; sBCC 2.38, 95% CI 2.30–2.47], with top earners having BCC tumours that were up to 9.7% smaller (95% CI 8.5–11.0%). The impact of distance to a dermatologist varied by KC subtype. For nBCC, increasing tumour incidence was noted with shorter distances to a dermatologist, while the opposite trend was seen for SCC and BD. Individuals living further away from a dermatologist had larger nBCC and sBCC tumours. No correlation between tumour size and distance to a dermatologist was found for SCC. Conclusions: High SES was associated with increased tumour incidence and smaller tumours for all KC subtypes, reflecting either higher rates of detection or higher rates of disease occurrence. Distance to a dermatologist was an independent predictor of KC burden, with shorter distances leading to increased tumour incidence but smaller nBCC tumours and decreased incidence of SCC.

Biosimilars are designed to be analogous to the biologic originators. However, comprehensive comparisons between biosimilars are limited and lacking for patients with psoriasis. This study’s objective was to compare 1-year drug survival of the 2 adalimumab biosimilars, GP2017 with SB5, following a non-medical mandatory switch from the adalimumab originator. Based on the national clinical database DERMBIO, this nationwide cohort study included all patients with psoriasis treated with the adalimumab originator who underwent a non-medical mandatory switch to GP2017 or SB5. The study included 525 patients switching from adalimumab originator to 1 of 2 biosimilars: GP2017 (n=267 patients) or SB5 (n=258 patients). When comparing the drug survival of the biosimilars, the hazard ratio was 1.11 (95% confidence interval, 0.58–2.12) for SB5 with GP2017 as reference. In the sensitivity analysis investigating changes in PASI, no differences were found when comparing the GP2017 group and the SB5 group at 120 days of follow-up (1.9% vs 1.6% improved, 1.9% vs 2.0% worsened, and 43.1% vs 40.9% remained unchanged). When comparing GP2017 and SB5, no discernible differences were found in drug survival or effectiveness based on PASI. Determining drug survival and effectiveness could benefit patients and clinicians in treatment decisions.

Background: Rates of keratinocyte carcinoma (KC) across Europe are impacted by population demographics and geography. Regional differences in KC occurrence exist, but few European studies investigate incidences of specific subtypes in the secondary healthcare sector on a national level.Objectives: To determine geographical differences in incidence rate and lifetime risk of KC subtypes across Denmark, including nodular and superficial basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and the KC precursor, Bowen's disease (BD), identified in office‐based dermatological practice.Methods: Based on a nationwide registry (The Danish Skin Cancer Registry), all patients in Denmark's five regions with a histologically‐ or clinically verified KC or BD registered in a state‐funded office‐based dermatology practice between 2013 and 2022 were included. Trends in national‐ and region‐specific age and sex standardised tumour incidence rates (STIR) were calculated. Further, national lifetime risk of each tumour subtype was estimated.Results: Between 2013 and 2022, the combined STIR for KC/BD rose 172% nationally from 180 to 489 per 100,000 person‐years (PY). This increase reflected rising rates of nodular BCC, SCC, and BD, while superficial BCC incidence was relatively stable. Regional differences in STIR for combined KC/BD were observed, with the Capital Region and North Jutland generally demonstrating higher rates than Zealand, Southern‐ and Central Denmark (e.g., North Jutland vs. Southern Denmark: 714 vs. 405/100,000PY). While the estimated lifetime risk of developing at least one KC or BD tumour was 21.8%, risk varied with tumour subtype, resulting in subtype‐specific risks of 16.4%, 5.1%, 1.9% and 1.3% for nodular BCC, superficial BCC, SCC, and BD, respectively.Conclusions: In Denmark's secondary dermatological care sector, incidence of nodular BCC, SCC and BD continues to rise with an overall lifetime risk nearing 22%. While KC incidence is increasing in Denmark, the study detected differences in geographical trends and rate increases of specific tumour subtypes.