Study Design
Employees signed a consent form for participation in the study and completed a standardized questionnaire. The questionnaire was based on surveys used in a prior study18 and collected information on current and prior skin lesions, prior dermatological screening, personal and family history of skin tumors, frequency of UV exposure, and type of UV protection used. For the question on measures taken for protection from UV radiation, possible answers included with sunscreen cream, with suitable sun-protective clothing, and by staying in the shade, or no measures were taken. In contrast to the other questions, multiple answers were accepted for this question. Answering no automatically excluded other possible answers. Participants also were asked to assess their own Fitzpatrick skin type19; the questionnaire included explanations of each skin type (I–IV).
The participants were then called in for examination by the dermatologist at 15-minute intervals. All clothing was removed and the skin was examined. Dermatoscopes were used for closer examination of suspicious skin lesions. The clinical results of the examinations were recorded on a standardized form.
An estimation of the number of melanocytic nevi—≤20, 21–49, or ≥50—was recorded for each patient. Suspicious skin lesions were assigned to one of the following categories: nevus requiring future checkup (Nc), nevus requiring excision (Ne), suspected malignant melanoma (MM), suspected squamous cell carcinoma, suspected basal cell carcinoma (BCC), suspected other skin tumor, and precancerous lesion. Fitzpatrick skin type also was assessed for all participants and recorded by the dermatologist carrying out the examination. Each participant was assigned to a risk group—low, moderate, or high risk—based on their individual risk for developing a skin tumor. Factors that were considered when determining participants’ risk for developing skin cancer included Fitzpatrick skin type, number of melanocytic nevi, personal and family history, leisure activities, UV protection used, and current clinical diagnosis of skin lesions.
After the skin examination, participants were informed of recommended treatment but were not given any additional dermatologic advice. Participants could arrange an appointment at the Department of Dermatology, University Hospital Erlangen, for the excision and histological analysis of the skin lesions. All recorded data were collected in a computerized spreadsheet program. When evaluating the questionnaires, questions that were not answered or were answered incorrectly (participant chose more than 1 answer) were ignored.
Statistical Analysis
Statistical analysis was carried out using SPSS software version 16.0. The majority of the data were nominal or ordinal. Metric data were checked for normal distribution using the Shapiro-Wilk test before carrying out parametric tests. Statistical tests were carried out using the χ2 test and the t test for independent samples. Non-nominal distributed data were checked using the Mann-Whitney U test. P<.05 was considered statistically significant in the exploratory data analysis.
Results
Of 783 employees included in the study, 288 (36.8%) were female and 495 (63.2%) were male (Table 1). In comparison with the total workforce, a significantly higher proportion of women than men took part in the cross-sectional study (P<.01). The average age (SD) was 42.3 (9.5) years (range, 18–64 years). Female participants (average age [SD], 39.8 [10.2] years) were significantly younger than male participants (average age [SD], 43.8 [8.8] years; P<.01). Forty-one percent of participants had a prior skin cancer screening. One percent of participants had a personal history of skin cancer, with 1 participant reporting a history of MM; 6.5% had a family history of skin cancer, of which 39.2% had a family history of MM.
The results of the clinical examinations showed that 43.8% of participants had 20 or fewer melanocytic nevi, 43.4% had 21 to 49 melanocytic nevi, and 12.8% had 50 or more melanocytic nevi. Significantly more women than men had 20 or fewer melanocytic nevi (P<.05).
Approximately 92% of participants assessed themselves as having Fitzpatrick skin types II (35.2%) or III (56.7%), while only approximately 3.6% and 4.5% assessed themselves as having skin types I and IV, respectively. The results of the Fitzpatrick skin type assessments made by dermatologists were similar: 96.9% of participants were assessed as having Fitzpatrick skin types II (43.0%) and III (53.8%); approximately 1.9% and 1.3% were assessed as having Fitzpatrick skin types I and IV, respectively. Results showed that 80.2% of all participants assessed their skin type in the same way as the dermatologist; 13.5% assessed their skin type as darker and 6.3% (49/783) assessed it as lighter. A quantitative analysis of Fitzpatrick skin type and sex showed that significantly more male participants than female participants assessed their Fitzpatrick skin type darker than their actual skin type (P<.01).
Overall, 47.6% of participants reported having had sunburn rarely in the past, while 36.9% and 14.0% had experienced sunburn once per year and several times per year, respectively. Approximately 1.4% of participants reported never having a sunburn. More of the male participants made use of comprehensive sun protection using all methods listed (34.5%; P<.05) or a combination of sunscreen and sun-protective clothing (14.9%; P<.01) than the female participants who relied more frequently on sunscreen alone (29.5%; P<.01) or a combination of sunscreen and staying in the shade (29.5%; P<.01)
In general it was clear that sunscreen, either alone or in combination with other sun-protection methods, was used most frequently (88.0%); 58.0% protected themselves by staying in the shade, while 48.0% used suitable sun-protective clothing. Only 3.6% of participants did not protect themselves using any of the suggested methods.
A total of 661 categorized skin lesions were found in 377 participants. Of these lesions, 491 were Nc and 121 were Ne. Twenty-four of the skin lesions were suspected precancerous lesions, 13 were suspected BCC, 2 were suspected MM, and 10 were suspected other skin tumor (Table 2). Overall, male participants who were diagnosed with at least 1 skin lesion (average age, 44.0 years) were significantly older than the women (average age, 39.3 years)(P<.01). Similar findings were observed in participants with at least 1 Nc (men, 43.3 years; women, 38.7 years; P<.01) and at least 1 Ne (men, 44.2 years; women, 38.0 years; P<.05). With regard to the individual risk for developing skin cancer, 32.6% of participants were considered to be at low risk, 64.9% were at moderate risk, and 2.6% were at high risk.
Approximately 61.5% of 377 participants who were diagnosed with at least 1 categorized skin lesion were advised to have a specific skin lesion checked by a dermatologist or to have a full examination for skin cancer once every 12 months. Furthermore, 22.5% were advised to follow-up biannually and 11.7% were advised to follow-up once every 2 years. Of the remaining participants who were advised to have follow-ups, 0.3% were advised to have a skin examination once every 3 months after having had MM, and 4.0% were advised to have follow-up once every 18 months. Overall, follow-up was recommended within 1 year in 84.4% of cases and within 1 to 2 years in 15.6% (Table 3).
Subsequent histological analysis of the excised tissue resulted in a diagnosis of only 21 clinically significant skin conditions. One case of Bowen disease and 1 case of BCC was confirmed. Histological analysis identified the remaining 19 excised skin lesions, which included the 2 suspected MMs, as dysplastic nevi.