The Burden of Multiple Basal Cell Carcinomas: A Population-wide Study.

Basal cell carcinoma (BCC) is a common skin cancer type and affected individuals are known to be at risk of developing multiple consecutive tumours. Research into BCC multiplicity has, thus far, been challenging, due to a lack of national registration. This registry-based cohort study aimed to analyse the occurrence of multiple BCCs in Sweden, and risk factors for subsequent primary BCCs. Data regarding all histopathologically verified, primary BCC tumours in Sweden from 2004 to 2017 was extracted from the Swedish BCC Registry. Risk of developing a subsequent BCC in relation to person-related factors was estimated with Cox regression analysis. Cumulative risk of BCC development after 1 or 3 earlier BCCs was estimated. In total, 39.9% of individuals with a registered BCC had at least 2 registered tumours. The risk of developing a subsequent BCC increased significantly in males, older age, and with residence in southern Sweden. The cumulative 5-year risk of developing an additional BCC after first diagnosis was approximately 30% in males and 27% in females and increased after multiple previous BCCs. This study showed the cumulative risk of a subsequent BCC to increase with a history of multiple BCCs, indicating the need for clinical surveillance in these individuals.

Incidence and trends of basal cell carcinoma in Sweden: a population-based registry study.

BACKGROUND: Basal cell carcinoma (BCC) is the most common skin cancer. Incidence is largely unknown because of incomplete, or lack of, registration in most countries. OBJECTIVES: To assess current incidence rates and recent trends for BCC in the Swedish population. METHODS: Patient- and tumour-related features of all histologically confirmed BCC tumours diagnosed in Sweden from 2004 to 2017 were extracted from the population-based Swedish BCC Registry. Incidence rates were standardized to the 2013 European Standard Population and trends were analysed using Poisson regression models. RESULTS: The age-standardized person-based incidence rate of BCC in Sweden was 405 per 100 000 in 2017, rising from 308 per 100 000 in 2004, corresponding to an annual relative increase of 1·8% (women, 2·1%; men, 1·4%). Incidence was highest in elderly people and the most common tumour site was the head and neck. In 2017, the most common BCC subtypes were nodular and micronodular/infiltrative BCC (each 31%). Incidence of aggressive BCC subtypes increased faster than other subtypes. CONCLUSIONS: BCC incidence rates in Sweden are relatively high and increasing. The increasing trends were more pronounced in women and for aggressive BCC subtypes. What is already known about this topic? Basal cell carcinoma (BCC) is the most common skin cancer in white populations and its incidence is increasing. BCC is seldom registered in national population-based cancer registries, therefore incidence estimates are extrapolated from small studies or incomplete registers. BCC occurs more often in men than in women and occurs most commonly on the head and neck, followed by the trunk. What does this study add? This study provides current BCC incidence rates for an entire European population. Sex-specific trends show that BCC incidence is increasing faster in women in Sweden. Aggressive BCC subtypes appear to be increasing faster than other subtypes.

Validity of ABCD Rule of Dermoscopy in Clinical Practice.

The ABCD rule of dermoscopy was developed to facilitate the dermoscopic differentiation between benign and malignant melanocytic lesions. However, there is a lack of studies on its validity in clinical practice. The aim of this study was to evaluate the accuracy of the algorithm used bedside, compared with the accuracy of the preliminary preoperative diagnosis, and to rate physicians' level of confidence in the diagnosis. Melanocytic tumours were preoperatively scored bedside, according to the ABCD algorithm; 309 cases (46 melanomas and 263 naevi) were included. A sensitivity of 83% and specificity of 45% were found for the ABCD algorithm. A comparable sensitivity (74%), but a significantly higher specificity (91%), was found for the preliminary diagnosis. Interestingly, there was a considerable percentage (19.6%) of early melanomas for which a malignant diagnosis was not preoperatively expected, indicating that it is important to maintain generous indications for excision or to practise short-term follow-up of ambiguous lesions in order to detect early melanomas.

Diagnosis of pigmented skin tumours in a dermatological setting: different aspects of the number needed to excise as a measure of efficiency.

The increasing incidence of melanoma prompts a need for efficient management of this patient group. In this study, we use the number needed to excise (NNE), as a measurement of the efficiency of diagnosing melanoma. From January 2009 to December 2012, postoperative records from all patients were prospectively registered. All excised tumours with the histopathological diagnosis of naevus, melanoma or seborrhoeic keratosis were included. NNE values, both excluding and including seborrhoeic keratosis, changes over time, as well as patient- and tumour-related factors influencing NNE were determined. In total, 1,717 cases were included. The overall NNE value was 6.5, and the value fell significantly (r = 0.959, p = 0.041) during the 4-year study period from 8.2 to 4.8. NNE values decreased with increasing patient age to 1.8 in patients ≥ 80 years of age. The overall NNE value including seborrhoeic keratosis was 6.8.

Accuracy of clinical skin tumour diagnosis in a dermatological setting.

The aim of this study was to evaluate the accuracy of preoperative diagnosis of skin tumours in a dermatological setting. Patients undergoing skin surgery at the Department of Dermatology without preoperative biopsy were prospectively enrolled. Preoperatively, a single clinical diagnosis was registered. The histopathological diagnosis, performed after excision, was registered as the correct diagnosis. The sensitivity and positive predictive value of the clinical diagnosis were calculated. A total of 2,953 tumours were included. Altogether, 55.1% of the excised lesions were malignant. Excision margins for malignant tumours were free from tumour cells in 96.0% of cases. The sensitivity for diagnosis of malignant tumour was 98.0% and the positive predictive value was 85.3%. In line with previous studies, the sensitivity and positive predictive value were highest for basal cell carcinoma, 95.4% and 85.9%, respectively. For squamous cell carcinoma, the corresponding values were 68.0% and 67.3%, and for melanoma, 70.6% and 51.3%.

Gold trichloride and gold sodium thiosulfate as markers of contact allergy to gold.

The usefulness of a trivalent gold salt, gold trichloride (GTC), was evaluated as a marker of contact allergy to gold. Patients patch test-positive or patch test-negative to gold sodium thiosulfate (GSTS), 13 subjects of each, were patch tested with dilution series of GTC and equimolar concentrations of GSTS. In order to avoid false-positive and false-negative test reactions, the salts were buffered and placed on polypropene chambers. Allergic reactions were registered in 9/13 gold-allergic patients with GSTS and in 2/13 with GTC. The sum of positive reactions was 18 with GSTS and 5 with GTC. Irritant reactions were none with GSTS and 2 with GTC in the gold-allergic patients. It is concluded that GTC can elicit positive patch test reactions in patients with gold allergy but to a lesser degree when compared with GSTS. Thus, GTC cannot be recommended in patch testing, and GSTS is still the test agent of choice.

Gold concentration in blood in relation to the number of gold restorations and contact allergy to gold.

Previous studies have demonstrated an association between gold allergy and the presence of dental gold restorations. The aim of the present study was to investigate the relationship between the concentration of gold in blood (B-Au) and the number of tooth surfaces with gold alloys in subjects with and without contact allergy to gold. In 80 patients referred for patch testing because of eczematous disease, blood samples were taken and analyzed for B-Au using inductively coupled plasma mass spectrometry. The detection limit for the Au determination was 0.04 microg/L. In addition, a dentist made a clinical and radiological examination of the patients and registered the number of dental gold surfaces. Patients with dental gold restorations had a statistically significantly higher B-Au in Mann-Whitney U test (P = 0.025), (range < 0.04-1.07 microg/L) than patients without (range < 0.04-0.15 microg/L). Furthermore, a positive correlation was found between B-Au and the number of dental gold surfaces (P < 0.01). There was no statistically significant difference in B-Au between persons with and without contact allergy to gold. The study thus indicates that gold is released from dental restorations and taken tip into the circulation.

Contact allergy to gold is correlated to dental gold.

Questionnaire studies have indicated that patients with dental gold will more frequently have contact allergy to gold. This study aimed at investigating the relationship between contact allergy to gold and the presence and amount of dental gold alloys. A total of 102 patients were referred for patch testing because of suspicion of contact allergy. Patch tests were performed with gold sodium thiosulphate 2% and 5%. The patients underwent an oral clinical and radiological examination. Contact allergy to gold was recorded in 30.4% of the patients, and of these 74.2% had dental gold (p=0.009). A significant correlation was found between the amount of gold surfaces and contact allergy to gold (p=0.008), but there was no statistical relationship to oral lesions. It is concluded that there is a positive relationship between contact allergy to gold and presence and amount of dental gold alloys.