Désirée Ratner

Background An epidemic of BCCs has led to a significant healthcare burden in Caucasian populations. Objectives To provide an update on incidence‐rates and tumor‐burden in an unselected, geographically isolated population that is exposed to a low level of UV radiation. Methods A whole population study using a cancer registry containing records of all BCC cases in 1981‐2017. We assessed BCC incidence according to age, residence and multiplicity and assessed trends using joinpoint‐analysis. Age‐standardized and age‐specific incidence rates were calculated along with cumulative and lifetime‐risks. Results Throughout the study period, the age standardized incidence rates increased from 25.7 to 59.9 for men, and from 22.2 to 83.1 for women (per 100.000). Compared to the single tumor‐burden, total tumor‐burden in the population was 1.72 times higher when accounting for multiplicity. In the beginning of the study period, the world‐standardized‐rates in men and women were similar, but by the end of the study period the rates were 39% higher in women (83.1, 95% CI [77.9‐88.3]) compared to men (59.9, 95% CI [55.6‐64.2]). This increase was most prominent in women years on sites that are normally not exposed to UV radiation in Iceland, the trunk and legs. Conclusions This is the only reported population in which the incidence of BCC is significantly higher in women than in men. The period of notable increase in BCC lesions correlates with the period of increase in tanning bed and travel popularity. The high multiplicity rates suggest that total tumor burden worldwide might be higher than previously thought.

BACKGROUND: Melanocytic immunostains can assist in margin evaluation of melanoma in situ (MIS) excisions; however, their accuracy and reliability relative to hematoxylin & eosin (H&E) is yet to be determined. OBJECTIVE: The objective of this study was to evaluate the sensitivity, specificity, and concordance of 4 melanocyte-specific immunostains for diagnosing MIS occurring on chronically sun-damaged skin. MATERIALS AND METHODS: Serial permanent sections from representative areas of negative margin and residual tumor were stained using H&E, MITF, MART-1, SOX10, and R21 and examined in a blinded fashion. The study set included 100 digital microscopy images from 10 cases of MIS excisions from the face. Two board-certified dermatopathologists, 4 fellowship-trained Mohs surgeons, 2 Mohs fellows, and 2 dermatology residents independently reviewed the 100 images. RESULTS: The average melanocyte density was 11 versus 28 melanocytes per 0.5 mm for chronically sun-damaged skin versus residual MIS on H&E, respectively. Statistically significantly higher melanocyte densities were observed using MITF, MART-1, and SOX10 on negative margins. The sensitivity and interobserver concordance was highest using MITF and SOX10. The intraobserver agreement on 4 duplicate images was 85%. CONCLUSION: In conclusion, the nuclear immunostains (MITF and SOX10) show the most promise for improving the diagnosis of MIS in chronically sun-damaged skin.