Patterns and timing of sunlight exposure and risk of basal cell and squamous cell carcinomas of the skin--a case-control study

A prospective cohort study exploring the joint influence of sunlight exposure and tanning bed use on basal cell carcinoma, squamous cell carcinoma, and melanoma risk

Exposure to solar ultraviolet (UV) radiation and use of UV-emitting tanning devices are known risk factors for skin cancer. Few studies have explored the interaction between these risk factors, namely how the risk of skin cancer increases among those who both have been exposed to high levels of natural sunlight and regularly use tanning beds. Nurses' Health Study II followed 116,430 women, aged 25-42, from 1991 to 2011. Cumulative average UV exposure was based on participants' residences at follow-up periods. History of severe sunburn during ages 15-20 was used as a proxy for early-life sunlight exposure. Tanning bed use in early life data was collected. Participants reported melanoma, basal cell carcinoma (BCC), and squamous cell carcinoma (SCC) diagnoses. We built multivariable Cox regression models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for risk of skin cancer associated with joint effects of sunlight exposure and tanning bed use. Participants with high sunlight exposure and tanning bed use during high school/college had an increased risk of BCC (HR = 1.53, 95% CI 1.37-1.71, Pinteraction=0.01; vs. low sun exposure and no tanning bed use). Participants with a history of severe sunburns and tanning bed use during high school/college were at increased risk of BCC (HR = 1.62, 95% CI 1.47-1.79, Pinteraction=0.02; vs. no sunburns and no tanning bed use). No significant interactions were found between sunlight exposure and tanning bed use on SCC and melanoma risk. We found significant interactions between sunlight exposure and tanning bed use on the risk of BCC.

Risk Factors and Innovations in Risk Assessment for Melanoma, Basal Cell Carcinoma, and Squamous Cell Carcinoma

Skin cancer is the most frequently diagnosed cancer globally and is preventable. Various risk factors contribute to different types of skin cancer, including melanoma, basal cell carcinoma, and squamous cell carcinoma. These risk factors encompass both extrinsic, such as UV exposure and behavioral components, and intrinsic factors, especially involving genetic predisposition. However, the specific risk factors vary among the skin cancer types, highlighting the importance of precise knowledge to facilitate appropriate early diagnosis and treatment for at-risk individuals. Better understanding of the individual risk factors has led to the development of risk scores, allowing the identification of individuals at particularly high risk. These advances contribute to improved prevention strategies, emphasizing the commitment to mitigating the impact of skin cancer.

Occupational solar exposure and basal cell carcinoma. A review of the epidemiologic literature with meta-analysis focusing on particular methodological aspects

BACKGROUND

Numerous epidemiologic studies and a few systematic reviews have investigated the association between occupational solar exposure and basal cell carcinoma (BCC). However, previous reviews have several deficits with regard to included and excluded studies/risk estimates and the assessment of risk of selection bias (RoSB). Our aim was to review epidemiologic studies with a focus on these deficits and to use meta-(regression) analyses to summarize risk estimates.

METHODS

We systematically searched PubMed (including MEDLINE) and Embase for epidemiologic studies. Study evaluation considered four main aspects of risk of bias assessments, i.e. Selection of subjects (selection bias); Exposure variables; Outcome variables; Data analysis.

RESULTS

Of 56 identified references, 32 were used for meta-(regression) analyses. The overall pooled risk estimate for BCC comparing high/present vs. low/absent occupational solar exposure was 1.20 (95% CI 1.02-1.43); among studies without major deficits regarding data analysis, it was 1.10 (95% CI 0.91-1.33). Studies with low and high RoSB had pooled risk estimates of 0.83 (95% CI 0.73-0.93) and 1.95 (95% CI 1.42-2.67), respectively. The definitions of exposure and outcome variables were not correlated with study risk estimates. Studies with low RoSB in populations with the same latitude or lower than Germany had a pooled risk estimate of 1.01 (95% CI 0.88-1.15).

CONCLUSION

Due to the different associations between occupational solar exposure and BCC among studies with low and high RoSB, we reason that the current epidemiologic evidence base does not permit the conclusion that regular outdoor workers have an increased risk of BCC.

Childhood sunburn and risk of melanoma and non-melanoma skin cancer: a Mendelian randomization study

Previous evidence has suggested that childhood sunburn could be a risk factor for cutaneous malignant melanoma (MM) and non-melanoma skin cancer (NMSC). However, existing observational studies could not reveal the causal associations genetically. This study aimed to investigate whether there was a genetic causal relationship between childhood sunburn and skin cancers. Univariable Mendelian randomization (MR) and Causal Analysis Using Summary Effect analysis was carried out for causal estimates and evaluation for the horizontal pleiotropy. Multivariable MR and the mediation effects analysis were used to test whether the causal associations were mediated by potential confounders. A suggestively significant causal association between childhood sunburn and MM was indicated (OR = 4.74; 95% CI: 1.31-17.19; p = 1.79E-02). Genetically predicted childhood sunburn was significantly associated with increased risk of overall melanoma in situ (MIS) (OR = 4.02; 95% CI: 2.00-8.08; p = 9.40E-05), MIS of face (OR = 18.28; 95% CI: 5.28-63.35; p = 4.59E-06), and MIS of trunk (OR = 7.05; 95% CI: 2.06-24.13; p = 1.88E-03). Similar trends were found for childhood sunburn and NMSC (OR = 8.16; 95% CI: 6.07-10.99; p = 1.53E-20), including both basal cell carcinoma (BCC) (OR = 3.76; 95% CI:2.96-4.77; p = 2.19E-08) and squamous cell carcinoma (SCC) (OR = 7.44; 95% CI: 5.09-10.87; p = 2.19E-08). After adjustment for hair and skin color, facial ageing, vitamin D levels, body mass index, alcohol consumption, and smoking status, childhood sunburn showed an independent association with MIS, MIS of face, MIS of trunk, as well as NMSC, including both BCC and SCC. Mediation analysis showed no significant mediation effect. This study demonstrated a causal relationship between childhood sunburn and the risk of both MM and NMSC, which suggested that enhanced screening and prevention for childhood sunburn could contribute to the early detection and decreased risk of MM and NMSC.

Impact of UV Modifying Factors on the Incidence of Keratinocyte Carcinomas in Solid Organ Transplant Recipients: A Systematic Review

INTRODUCTION

Solid organ transplant recipients (SOTR) are at an increased risk for developing keratinocyte carcinomas (KC). Four ultraviolet (UV) modifying factors have been identified that impact the incidence of KC: Fitzpatrick Skin Type (FST), race, sun exposure, and sun-protective factors.

OBJECTIVES

We conducted a systematic review to summarize the association between UV modifying factors and the incidence of KC in SOTR.

METHODS

We systematically searched PubMed, Scopus, and Web of Science databases, and after screening for inclusion and exclusion criteria, we included 13 studies with 6,910 solid organ transplant recipients in our analysis.

RESULTS

Our review found that lower FST (I-II), white and Latinx populations, lack of regulated sunscreen application, and occupational and residential sun exposure are individual risk factors among solid organ transplant recipients for KC incidence. Although previous studies showed an in-creased SCC:BCC ratio, some studies found a contradictory increased BCC:SCC ratio. Limitations include few research studies that analyze these UV modifying factors and a lack of incorporating both varying immunosuppressant factors and transplantation follow-up times.

CONCLUSIONS

These findings support the need for dermatological advice in increased risk patient demographic populations, lower FST and white and Latinx populations, and subsequently moderating sun exposure and protective factors.

A meta-analysis of sunburn and basal cell carcinoma risk

Basal cell carcinoma (BCC) is the most common cancer in the United States. Sunburn is a modifiable risk factor for BCC. The objective of this project was to synthesize research on BCC and sunburn to quantify the impact and severity of sunburn at different life stages on BCC risk in the general population. A systematic literature search of four electronic databases was conducted and data were extracted by two independent reviewers using standardized forms. Data from 38 studies were pooled using both dichotomous and dose-response meta-analytic methods. BCC risk increased with ever experiencing a sunburn in childhood (OR=1.43, 95% CI: 1.19, 1.72) and with ever experiencing a sunburn in life (OR= 1.40, 95% CI: 1.02, 1.45). Every five sunburns experienced per decade in childhood increased BCC risk by 1.86 (95% CI: 1.73, 2.00) times. Every five sunburns experienced per decade in adulthood increased BCC risk by 2.12 (95% CI: 1.75, 2.57) times and every five sunburns per decade of life increased BCC risk by 1.91 (95% CI: 1.42, 2.58) times. The data on sunburn exposure and BCC show that an increase in number of sunburns at any age increased the risk of BCC. This may inform future prevention efforts.

Sun Protection Behavior Following Skin Cancer Resection and Reconstruction

Increased exposure to ultraviolet radiation (UVR) is associated with an increased risk of nonmelanoma skin cancer. Cutaneous surgery can be negatively influenced by UVR, causing delayed wound healing, hyperpigmentation of the scar, and an increased incidence of additional skin cancers. By changing sun protection behavior, these risks can be limited. Therefore, this study evaluates changes in patients' sun protective behavior after Mohs micrographic surgery (MMS). Patients undergoing MMS between December 2017 and November 2019 were included. Patients were asked to complete the FACE-Q Skin Cancer - Sun Protection Behavior checklist before and 3 months and 1 year post-surgery. A total of 125 patients completed the pre-operative and 3-months post-operative checklists, and 89 (71.2%) completed the 1-year post-operative checklist. Reported sun protective behaviors increased post-surgery at all time points (p < 0.001). Patients with a prior history of facial skin cancer demonstrated a larger increase in sun protection behaviors after surgery than patients without a history of facial skin cancer (p = 0.04). Patients with defects located on the ear or scalp demonstrated a lesser increase in sun protection behaviors than patients with defects located in more conspicuous areas as the face (p = 0.02). Our study demonstrates a change in sun protection behavior, with an increase in sun protection behavior over time in patients after MMS. However, more improvement is possible. Targeted counseling can increase sun protection behavior in patients without a history of facial skin cancer and patients with skin cancer located on the ears or scalp.

An Exploration of the Use and Impact of Preventive Measures on Skin Cancer

Background: Skin cancer is the most common form of cancer, and both clinical and epidemiological data link cumulative solar dosages and the number of sunburns to skin cancer. Each year, more than 5.4 million new cases of skin cancer are diagnosed, incurring a significant health and financial burden. Recommended preventive measures for skin cancer include the use of sunscreen, sun avoidance, and protective clothing. This study used a national database to examine the association of preventive measures with the prevalence of skin cancer, specifically analyzing the preventive measures of sunscreen use, staying in the shade, and wearing long-sleeved shirts. The second aim was to determine which characteristics, if any, correlated with using prevention measures. Methods: This study analyzed data from the National Health and Nutritional Examination Survey 2015−2016 cycle to examine the association of three preventive measures (using sunscreen, staying in the shade, and wearing long-sleeved shirts) with skin cancer. Logistic regression and chi-square tests were utilized to examine the relationship between skin cancer and these prevention methods. Results: Sunscreen use (OR = 3.752; p < 0.05) was statistically associated with a lower prevalence of skin cancer, while wearing long-sleeved shirts (OR = 6.911; p = 0.064) and staying in the shade (OR = 0.646; p = 0.481) did not emerge as factors significantly associated with a lower prevalence after controlling for gender, race/ethnicity, marital status, income, health insurance, and general health. Additionally, men and individuals of color were less likely to use sunscreen. Conclusion: Sunscreen use was associated with a lower prevalence of skin cancer, while wearing long-sleeved shirts and staying in the shade was not significantly linked to lower rates of skin cancer, suggesting that these measures may not be as effective as sunscreen for preventing skin cancer. Men and individuals of color were significantly less likely to use sunscreen. These findings can help guide future education efforts and research regarding skin cancer prevention and suggest the need to develop male-oriented programs to mitigate the gender disparity in employing sun-protection measures.

Sunscreens With High Versus Low Sun Protection Factor and Cutaneous Squamous Cell Carcinoma Risk: A Population-Based Cohort Study

Evidence on sunscreen use and cutaneous squamous cell carcinoma (cSCC) risk is limited. Most studies have not taken sun protection factor (SPF) into consideration and used nonusers of sunscreen as the reference group. Nonusers are likely a priori at lower cSCC risk than users. No study has investigated the effect of high- versus low-SPF sunscreens on cSCC, appropriately adjusting for time-varying confounding. Using data from the Norwegian Women and Cancer Study (1991–2016), we investigated whether use of SPF ≥15 versus SPF <15 sunscreens reduces cSCC risk. We used a marginal structural Cox proportional hazards model with inverse probability of treatment and censoring weights to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). During follow-up of 148,781 women (mean follow-up, 14.3 years), 653 women were diagnosed with cSCC. The effect on cSCC risk of sunscreens with SPF ≥15 versus SPF <15 was close to the null when used at any latitudes (HR = 1.02, 95% CI: 0.82, 1.27) and when used in lower-latitude settings (HR = 1.05, 95% CI: 0.84, 1.32). In conclusion, we found no indication that sunscreens with SPF ≥15 reduced Norwegian women’s cSCC risk more than sunscreens with SPF <15, suggesting that either there is no difference in their effects long-term or the difference is diluted by incorrect application.

Dietary components and the risk of non-melanoma skin cancer: A systematic review of epidemiological studies

Non-melanoma skin cancer (NMSC) is the most common cancer among white-skinned people. The main environmental risk factor for all types of skin cancer is ultraviolet (UV) exposure to the sun. However, significant modifiable risk factors, such as diet, have been studied about NMSC risk. Several original studies have been conducted on the link between various dietary components and the risk of NMSC in the past decade, but have not been systematically reviewed. This review focuses on the potential impact of dietary components in the prevention of NMSC and evaluates the findings of epidemiologic evidence for dietary factors. We conducted a systematic search of three databases, including Scopus, ISI Web of Science, and PubMed, to identify relevant epidemiological studies published between 2000 and July 6, 2021. Finally, forty-three articles were included. Because of the inherent limitations of epidemiological studies, no definitive conclusions can be drawn; however, the links between folate, citrus, caffeine, and alcohol with BCC are notable; thus, high dietary folate intake, as well as citrus and alcohol consumption, are associated with an increased risk of basal cell carcinoma (BCC), whereas caffeine is associated with a lower risk. More research is required to reach a definitive conclusion.

New Developments in the Management of Cutaneous Squamous Cell Carcinoma

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. List important prognostic features that affect cutaneous squamous cell carcinoma risk. 2. Summarize the changes to the AJCC Cancer Staging Manual, Eighth Edition, staging system for cutaneous squamous cell carcinoma. 3. Evaluate the draining nodal basin with appropriate imaging modalities. 4. Recommend adjuvant radiation therapy in the correct clinical setting for high-risk tumors. 5. Recognize the currently available treatments for advanced cutaneous squamous cell carcinoma.

SUMMARY

This continuing medical education article reviews the features, management, and prognosis of cutaneous squamous cell carcinoma with an emphasis on high-risk squamous cell carcinoma and data from the past 3 years. This review will discuss the primary tumor management, high-risk features of a squamous cell carcinoma, changes to the American Joint Committee on Cancer staging system, and the utility of sentinel lymph node biopsy, and critically review the evidence regarding adjuvant therapy.

Ultraviolet Radiation and Basal Cell Carcinoma: An Environmental Perspective

Ultraviolet radiation (UVR) is a known carcinogen participated for the development of skin cancers. Solar UVR exposure, particularly ultraviolet B (UVB), is the mostly significant environmental risk factor for the occurrence and progress of basal cell carcinoma(BCC). Both cumulative and intermittent high-grade UVR exposure could promote the uncontrolled replication of skin cells. There are also exsiting other contributing environmental factors that combine with the UVR exposure to promote the development of BCC. DNA damage in formation of skin cancers is considered to be a result of UVR toxicity. It is UVR that could activate a series of oncogenes simultaneously inactivating tumor suppressor genes and aberrant proliferation and survival of keratinocytes that repair these damages. Furthermore, mounting evidence demonstrates that inflammatory responses of immune cells in the tumor microenvironment plays crucial role in the skin tumorigenesis as well. In this chapter, we will follow the function of UVR in the onset and development of BCC. We describe the factors that influence BCC induced by UVR, and also review the recent advances of pathogenesis of BCC induced by UVR from the genetic and inflammatory aspects.

Association of Lifetime Indoor Tanning and Subsequent Risk of Cutaneous Squamous Cell Carcinoma

Importance

No study, to our knowledge, has prospectively investigated a dose-response association between lifetime indoor tanning and risk of cutaneous squamous cell carcinoma (SCC).

Objective

To investigate the dose-response association between lifetime indoor tanning and SCC risk, the association between duration of use and age at initiation with SCC risk, and the association between age at initiation and age at diagnosis.

Design, Setting, and Participants

This cohort study included data from women born from 1927 to 1963 from the Norwegian Women and Cancer study, established in 1991 with follow-up through December 31, 2015. Baseline questionnaires were issued to participants from 1991 to 2007, with follow-up questionnaires given every 5 to 7 years. Data analysis was performed from January 2, 2018, to March 2, 2019.

Exposures

Participants reported pigmentation factors. Sunburns, sunbathing vacations, and indoor tanning were reported for childhood, adolescence, and adulthood.

Main Outcomes and Measures

Information on all cancer diagnoses and dates of emigration or death were obtained through linkage to the Cancer Registry of Norway, using the unique personal identification number of Norwegian citizens.

Results

A total of 159 419 women (mean [SD] age at inclusion, 49.9 [8.3] years) were included in the study. During follow-up (mean [SD], 16.5 [6.4] years), 597 women were diagnosed with SCC. Risk of SCC increased with increasing cumulative number of indoor tanning sessions. The adjusted hazard ratio (HR) for highest use vs never use was 1.83 (95% CI, 1.38-2.42; P < .001 for trend). A significantly higher risk of SCC was found among women with 10 years or less of use (HR, 1.41; 95% CI, 1.08-1.85) and more than 10 years of use (HR, 1.43; 95% CI, 1.16-1.76) and among women with age at initiation of 30 years or older (HR, 1.36; 95% CI, 1.11-1.67) and younger than 30 years (HR, 1.51; 95% CI, 1.18-1.92) vs never users. No significant association was found between age at initiation and age at diagnosis (estimated regression coefficient, -0.09 [95% CI, -1.11 to 0.94] for age at initiation of ≥30 years and -0.02 [95% CI, -1.27 to 1.22] for <30 years vs never use).

Conclusion and Relevance

The findings provide supporting evidence that there is a dose-response association between indoor tanning and SCC risk among women. The association between cumulative exposure to indoor tanning and SCC risk was the same regardless of duration of use and age at initiation. These results support development of policies that regulate indoor tanning.

Cutaneous viral infections associated with ultraviolet radiation exposure

The complex interplay between ultraviolet radiation (UVR) and cutaneous viral infections in the context of cancer etiology is challenging to unravel, given the limited information on the independent association between UVR and cutaneous viral infections. Using multiple biomarkers of infection with 24 types of cutaneous human papillomavirus (HPV) and 4 types of polyomaviruses (HPyV), we investigated cross-sectional associations with recent UVR exposure, using skin pigmentation measured by spectrophotometer. Age- and sex-adjusted associations between UVR and viral seropositivity, viral DNA present in eyebrow hairs (EBH) and skin swabs (SSW) were estimated using logistic regression. Beta-HPV seropositivity was associated with viral DNA positivity in EBH (OR = 1.40, 95% CI = 1.05-1.88) and SSW (OR = 1.86, 95% CI = 1.25-2.74). Similar associations were observed for Merkel cell polyomavirus. Participants in the highest tertile of UVR exposure were more likely to be seropositive for beta-HPV (OR = 1.81, 95% CI = 1.16-2.38), and have beta-HPV DNA in EBH (OR = 1.57, 95% CI = 1.06-2.33) and SSW (OR = 2.22, 95% CI = 1.25-3.96), compared to participants with the lowest tertile of UVR exposure. UVR exposure was positively associated with three different markers of beta-HPV infection. Therefore, future studies of HPV associated KC development should address more directly the role of HPV and UVR exposure as potential co-carcinogens.

Assessment of sun-related behavior and serum vitamin D in basal cell carcinoma: Preliminary results

Ultraviolet radiation (UV), mainly from sunlight, is the main risk factor of the most common human skin cancer, basal cell carcinoma (BCC). A positive effect of UV on the skin is its contribution to the synthesis of vitamin D, which is important in sustaining general health, but having high levels of vitamin D is considered a risk factor for BCC. However, vitamin D receptor has antagonistic effects to UV radiation in regulating Sonic Hedgehog pathway. This is a pilot study aimed at characterizing the sun-related behavior and vitamin D status of 52 BCC patients and 59 controls from our geographical area. Patients were included in 4 subgroups: Single, multiple, recurrent, and both multiple and recurrent BCCs. Patients, more than controls, had at least one sunburn in childhood and lentigines (P<0.001). Also, they spent daily, on average, more time in the sun than controls (P<0.001) (3.00-8.00 and 1.50-4.00 h respectively). Outdoor work was similar in both groups. Participants had lower vitamin D serum levels than expected. Due to the small number of cases, no statistically significant differences were found between the subgroups but some tendencies were noted. Patients with only one recurrent BCC had less sunburns than the ones who also developed tumors at multiple sites (P=0.2). Patients with multiple and recurrent tumors had slightly lower vitamin D levels compared with single BCC patients (P=0.1) although they used more vitamin D supplements after the BCC diagnosis (P=0.2). Having a diagnosis of BCC, made patients more compliant to the use of sunscreen cream, but even so, half of them still did not use it. In conclusion, more effort should be invested in sun-related education and public health actions should focus on vitamin D deficiencies.

Global evidence on occupational sun exposure and keratinocyte cancers: a systematic review

Individual studies have suggested that the association between occupational exposure to solar ultraviolet radiation (UVR) and the development of keratinocyte cancers (KCs) may only be valid in populations of European ancestry living in certain geographical regions. Comparative global data are scarce and so this review aimed to summarize current evidence on the association between occupational exposure to solar UVR and the development of KCs, with a specific focus on geographical location and skin colour. Ovid MEDLINE, PubMed, Embase and Web of Science were searched for potentially relevant records. Extracted data were summarized by study, country and region. We included one prospective cohort study and 18 case-control studies (n = 15 233) from 12 countries in regions where the majority of the population is white skinned (Americas, Europe and Oceania). Eighteen of the 19 studies reported effect estimates suggesting an increased risk of basal cell carcinoma (BCC) and/or squamous cell carcinoma (SCC) among outdoor workers. Only 11 studies found a significantly increased risk and many had imprecise estimates. There was a significantly increased risk of BCC and SCC in individual studies in North America, Latin America and the Caribbean, Western Europe and Southern Europe, but not across regions or countries. Overall, 95% of studies reported higher risks among outdoor workers, although the increases in risk were statistically significant in just over half of the studies. Well-designed and sufficiently powered occupational case-control and cohort studies with adequate adjustment for confounding factors and other risk factors are required to provide more accurate risk estimates for occupational KC.

Summer sun-exposure in Australian childhood cancer survivors and community reference groups

PURPOSE

Sun-exposure can cause health problems, including melanoma and nonmelanoma skin cancer, especially in Australia where the incidence of skin cancer is particularly high. Childhood cancer survivors (CCSs) have an augmented risk due to previous cancer history and treatment. Despite recommendations advising sun protection, CCSs may be placing themselves at risk. We considered daily summer sun-exposure in an Australian cohort of CCSs and in community reference groups, and identified factors associated with sun-exposure in these populations.

METHODS

Summer sun-exposure data were collected on 471 CCSs (119 parents of survivors aged <16, and 352 survivors aged ≥16) and a reference group of 470 participants from the community (155 parents of children aged <16, and 355 adults aged ≥16). Survivors completed paper questionnaires and the reference groups completed an online survey. Medical records confirmed survivors' clinical information. Ordinal logistic regressions identified factors associated with daily summer sun-exposure.

RESULTS

More daily summer sun-exposure was reported by both parents reporting for the young survivors (U = 5,522.5, P < .001; U = 31,412, P < .001) and by older survivors (U = 5,039.5, P < .001; U = 29,913, P < .001). Among younger participants greater sun-exposure was associated with being a CCS, while in older participants, greater sun-exposure was associated with being a CCS, a male, smoker/ex-smoker and was also increased in those with more sensitive skin reaction to sunlight. Focusing only on the CCSs, when treatments were considered, none statistically predicted sun-exposure in young CCSs while older CCSs who received radiotherapy were less likely to spend excess time in the sun.

CONCLUSION

CCSs have sun-exposure at times of day when sun-related skin damage is highest, despite advice to avoid highest risk times. This data can inform sun-protection programs and lifestyle advice aimed at ameliorating the potential increased risk of skin cancer in CCSs.

Assessment of Predictors of Sun Sensitivity as Defined by Fitzpatrick Skin Phototype in an Ecuadorian Population and Its Correlation with Skin Damage

BACKGROUND

The Fitzpatrick skin phototype scale (FSPTS) is a widely used instrument to assess skin type.

METHODS

A cross-sectional survey collected responses from 254 subjects from Quito regarding self-reported FSPTS, gender, age, education, and tobacco and alcohol consumption. Univariate and multivariate logistic regression analyses were performed to determine if ethnicity, hair color, and eye color significantly predict FSPTS. In addition, we studied the correlation between FSPTS and the SCINEXA scale with Pearson's correlation coefficient.

RESULTS

Ethnicity, eye color, and hair color are significant independent predictors of FSPTS (p < 0.0001).

CONCLUSIONS

Patient self-reported race and pigmentary phenotypes are inaccurate predictors of sun sensitivity as defined by Fitzpatrick skin phototype. Our study does not fully represent the population of the country. There are limitations to using patient-reported race and appearance in predicting individual sunburn risk.

Health Characteristics of the Wayuu Indigenous People

INTRODUCTION

The identified number of isolated populations with unique medical characteristics is growing. These populations are difficult to study. Civil-military humanitarian operations are part of our medical force readiness training, and are also a venue through which unique populations can be simultaneously served and evaluated. Continuing Promise 2017 was a collaborative effort between the US Navy, non-governmental organizations, and the Colombian Ministry of Health, Navy and Army to provide primary medical care to the Wayuu indigenous people in the La Guajira Department of Colombia.

MATERIALS AND METHODS

In the course of providing primary care services, demographic and health data of the Wayuu people were collected. Descriptive statistics were used to generate averages, and t-tests were used to compare Wayuu means with age and gender matched US means for weight and age in children and blood pressure in adults. Observational data on skin afflictions and arthritis were also collected. This project was approved by Naval Medical Center Portsmouth Institutional Review Board.

RESULTS

Although the Wayuu live in an arid desert with chronic sun exposure, they have no apparent affliction from squamous cell carcinoma or melanoma. They live almost exclusively through manual labor, yet rarely develop osteoarthritic joint disease. Their incidence of hypertension is 35% lower than their US age and gender matched cohort. Although their region is known for extreme poverty and malnutrition, their weight-for-age curve from 2 months through 17 years is similar to their US cohort.

CONCLUSIONS

This study is the first to document the general health characteristics of the Wayuu people. It demonstrates that in addition to providing important readiness training to our own personnel, humanitarian missions can provide medical care and explore unique, isolated populations. Although retrospective and limited in size, it can be used to shape future medical missions to their region, and will hopefully stimulate formal research into their remarkable characteristics.

Extremity nevus count is an independent risk factor for basal cell carcinoma and melanoma, but not squamous cell carcinoma

BACKGROUND

The presence of nevi portends an increased risk for melanoma.

OBJECTIVE

We sought to examine the association between extremity nevus count and the risk of melanoma and keratinocyte cancers.

METHODS

We evaluated prospective cohorts of 176,317 women (the Nurses' Health Study, 1986-2012 and the Nurses' Health Study 2, 1989-2013) and 32,383 men (Health Professionals Follow-up Study, 1986-2012). Information on nevus count (none, 1-5, 6-14, ≥15) on the extremity was collected at baseline.

RESULTS

There were 1704 incident cases of melanoma, 2296 incident cases of squamous cell carcinoma, and 30,457 incident cases of basal cell carcinoma, with a total of 4,655,043 person-years for melanoma and 4,267,708 person-years for keratinocyte cancers. The presence of an extremity nevus was associated with an increased risk of melanoma in all anatomic areas and increased risk of basal cell carcinoma (BCC). Individuals with ≥15 nevi had the highest risk of melanoma and BCC compared to those without any extremity nevi (melanoma hazard ratio 2.79 [95% confidence interval 2.04-3.83]; BCC HR 1.40 [95% confidence interval 1.32-1.49]). No significant association was observed for squamous cell carcinoma.

LIMITATIONS

Limitations of our study included self-reported nevus count and detection bias.

CONCLUSIONS

Extremity nevus count is a helpful clinical marker in risk-stratifying individuals for BCC and melanoma on all body sites.

Nonmelanoma skin cancer in women

Men continue to develop nonmelanoma skin cancer (NMSC) at higher rates than women, but the epidemiologic pattern of NMSC development is evolving. We present a selective, narrative review of the literature showing that there is a trend toward a development of basal cell carcinomas in women at younger ages, and highlight potential causes of this trend. We review evidence that indoor tanning is associated with the development of NMSC and show that young women use indoor tanning more than any other age-sex group. We discuss societal factors that relate to the tanning behavior of young women. Finally, we argue that facial NMSCs may have more of a negative impact on quality of life in women than in men.

Promoting sunscreen use and skin self-examination to improve early detection and prevent skin cancer: quasi-experimental trial of an adolescent psycho-educational intervention

Background

Skin cancer rates are increasing. Interventions to increase adolescent sunscreen use and skin self-examination (SSE) are required.

Methods

Quasi-experimental design; 1 control and 4 intervention group schools in Scotland, UK. Participants were 15–16 year old students on the school register. The intervention was a theoretically-informed (Common-Sense Model and Health Action Process Approach) 50-min presentation, delivered by a skin cancer specialist nurse and young adult skin cancer survivor, to students in a classroom, supplemented by a home-based assignment. Outcome variables were sunscreen use intention, SSE intention/behaviour, planning, illness perceptions and skin cancer communication behaviour, measured 2 weeks pre- and 4 weeks post- intervention using self-completed pen and paper survey. School attendance records were used to record intervention up-take; students self-reported completion of the home-based assignment. Pearson’s chi-square test, analysis of variance, and non-parametric Wilcoxon Signed Ranks Test were used to measure outcomes and associations between variables. Focus groups elicited students’ (n = 29) views on the intervention. Qualitative data were analysed thematically.

Results

Five of 37 invited schools participated. 639 (81%) students in intervention schools received the intervention; 33.8% completed the home-based assignment. 627 (69.6%) of students on the school register in intervention and control schools completed a questionnaire at baseline; data for 455 (72.6%) students were available at baseline and follow-up. Focus groups identified four themes – personal experiences of skin cancer, distaste for sunscreen, relevance of SSE in adolescence, and skin cancer conversations. Statistically significant (p < 0.05) changes were observed for sunscreen use, SSE, planning, and talk about skin cancer in intervention schools but not the control. Significant associations were found between sunscreen use, planning and 2 illness perceptions (identity and consequence) and between SSE, planning and 3 illness perceptions (timeline, causes, control).

Conclusions

It is feasible to promote sunscreen use and SSE in the context of an adolescent school-based psychoeducation intention. Further research is required to improve study uptake, intervention adherence and effectiveness.

Trial registration

ISRCTN11141528

Electronic supplementary material

The online version of this article (10.1186/s12889-018-5570-y) contains supplementary material, which is available to authorized users.

Patterns of Ultraviolet Radiation Exposure and Skin Cancer Risk: the E3N-SunExp Study

BACKGROUND

While ultraviolet (UV) radiation exposure is a recognized risk factor for skin cancer, associations are complex and few studies have allowed a direct comparison of exposure profiles associated with cutaneous melanoma, basal-cell carcinoma (BCC), and squamous-cell carcinoma (SCC) within a single population.

METHODS

We examined associations between UV exposures and skin cancer risk in a nested case-control study within E3N, a prospective cohort of 98,995 French women born in 1925-1950. In 2008, a lifetime UV exposure questionnaire was sent to all reported skin cancer cases and three controls per case, which were matched on age, county of birth, and education. Analyses were performed using conditional logistic regression and included 366 melanoma cases, 1,027 BCC cases, 165 SCC cases, and 3,647 controls.

RESULTS

A history of severe sunburns <25 years was associated with increased risks of all skin cancers (melanoma: OR 2.7; BCC: OR 1.7; SCC: OR 2.0 for ≥6 sunburns vs. none), while sunburns ≥25 years were associated with BCC and SCC only. While high-sun protection factor sunscreen use before age 25 was associated with lower BCC risk (Ptrend = 0.02), use since age 25 and reapplication of sunscreen were associated with higher risks of all three types of skin cancer. There were positive linear associations between total UV score and risks of BCC (Ptrend = 0.01) and SCC (Ptrend = 0.09), but not melanoma. While recreational UV score was strongly associated with BCC, total and residential UV scores were more strongly associated with SCC.

CONCLUSIONS

Melanoma, BCC, and SCC are associated with different sun exposure profiles in women.

Emerging concepts and recent advances in basal cell carcinoma

Basal cell carcinoma (BCC) is the most common malignancy worldwide, arising from non-keratinizing cells within the basal layer of the epidermis. The incidence of BCC continues to rise annually, increasing the burden of management of these carcinomas and the morbidity associated with their treatment. While surgical interventions such as Mohs micrographic surgery and surgical excision are the standard of care and yield the highest cure rates, the number of non-surgical interventions approved for the treatment of BCC continues to expand. We review various surgical and non-surgical approaches to the treatment of BCC, focusing on targeted molecular therapies that are approved for locally advanced or recurrent disease.

Mitochondrial DNA deletion percentage in sun exposed and non sun exposed skin

The percentages of mitochondrial genomes carrying the mtDNA³⁸⁹⁵ and the mtDNA⁴⁹⁷⁷ (common) deletion were quantified in sun exposed and non sun exposed skin biopsies, for five cohorts of patients varying either in sun exposure profile, age or skin cancer status. Non-melanoma skin cancer diagnoses are rising in Ireland and worldwide [12] but most risk prediction is based on subjective visual estimations of sun exposure history. A quantitative objective test for pre-neoplastic markers may result in better adherence to sun protective behaviours. Mitochondrial DNA (mtDNA) is known to be subject to the loss of a significant proportion of specific sections of genetic code due to exposure to ultraviolet light in sunlight. Although one such deletion has been deemed more sensitive, another, called the mtDNA⁴⁹⁷⁷ or common deletion, has proved to be a more useful indicator of possible risk in this study. Quantitative molecular analysis was carried out to determine the percentage of genomes carrying the deletion using non sun exposed and sun exposed skin biopsies in cohorts of patients with high or low sun exposure profiles and two high exposure groups undergoing treatment for NMSC. Results indicate that mtDNA deletions correlate to sun exposure; in groups with high sun exposure habits a significant increase in deletion number in exposed over non sun exposed skin occurred. An increase in deletion percentage was also seen in older cohorts compared to the younger group. The mtDNA³⁸⁹⁵ deletion was detected in small amounts in exposed skin of many patients, the mtDNA⁴⁹⁷⁷ common deletion, although present to some extent in non sun exposed skin, is suggested to be the more reliable and easily detected marker. In all cohorts except the younger group with relatively lower sun exposure, the mtDNA⁴⁹⁷⁷ deletion was more frequent in sun exposed skin samples compared to non-sun exposed skin.

Coffee, tea and caffeine intake and the risk of non-melanoma skin cancer: a review of the literature and meta-analysis

PURPOSE

Laboratory studies suggested that caffeine and other nutrients contained in coffee and tea may protect against non-melanoma skin cancer (NMSC). However, epidemiological studies conducted so far have produced conflicting results.

METHODS

We performed a literature review and meta-analysis of observational studies published until February 2016 that investigated the association between coffee and tea intake and NMSC risk. We calculated summary relative risk (SRR) and corresponding 95 % confidence intervals (95 % CI) by using random effects with maximum likelihood estimation.

RESULTS

Overall, 37,627 NMSC cases from 13 papers were available for analysis. Intake of caffeinated coffee was inversely associated with NMSC risk (SRR for those in the highest vs. lowest category of intake: 0.82, 95 % CI 0.75-0.89, I ² = 48 %), as well as intake of caffeine (SRR 0.86, 95 % CI 0.80-0.91, I ² = 48 %). In subgroup analysis, these associations were limited to the basal cell cancer (BCC) histotype. There was no association between intake of decaffeinated coffee (SRR 1.01, 95 % CI 0.85-1.21, I ² = 0) and tea (0.88, 95 % CI 0.72-1.07, I ² = 0 %) and NMSC risk. There was no evidence of publication bias affecting the results. The available evidence was not sufficient to draw conclusions on the association between green tea intake and NMSC risk.

CONCLUSIONS

Coffee intake appears to exert a moderate protective effect against BCC development, probably through the biological effect of caffeine. However, the observational nature of studies included, subject to bias and confounding, suggests taking with caution these results that should be verified in randomized clinical trials.

Long-term ultraviolet flux, other potential risk factors, and skin cancer risk: a cohort study

BACKGROUND

Few prospective studies have examined the relationship between sun exposure, other potential risk factors, and risk of different skin cancers [including basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma] simultaneously.

METHODS

We evaluated the association between a number of potential risk factors and skin cancer risk in a cohort of 108,916 US women, the Nurses' Health Study II (1989-2009).

RESULTS

During 2.05 million years of follow-up, we identified 6,955, 880, and 779 diagnoses of BCC, SCC, and melanoma, respectively. Compared with participants in the lowest quintile of cumulative ultraviolet flux in adulthood, participants in the highest quintile had multivariable-adjusted relative risks (RR) of 2.35 (Ptrend < 0.0001) for BCC, 2.53 (Ptrend = 0.009) for SCC, and 0.68 (Ptrend = 0.38) for melanoma. In contrast, the RRs were 1.68 (95% CI, 1.55-1.82) for BCC, 1.68 (95% CI, 1.34-2.11) for SCC, and 1.80 (95% CI, 1.42-2.28) for melanoma for participants with ≥5 blistering sunburns when compared with participants without sunburn between ages 15 and 20 years. We found significant interactions between family history of melanoma, number of blistering sunburns between ages 15 and 20 years and BCC risk, and between sunburn reaction as a child/adolescent and SCC risk (all Pinteraction < 0.05).

CONCLUSION

In a cohort of U.S. women, we found that sun exposures in both early life and adulthood were predictive of BCC and SCC risks, whereas melanoma risk was predominantly associated with sun exposure in early life.

IMPACT

Our results may have potential implications for the prevention of skin cancers. Cancer Epidemiol Biomarkers Prev; 23(6); 1080-9. ©2014 AACR.

History of Severe Sunburn and Risk of Skin Cancer Among Women and Men in 2 Prospective Cohort Studies

Few studies have assessed the relationship between sunburn and risk of different skin cancers (melanoma, squamous cell carcinoma (SCC), and basal cell carcinoma (BCC)) in prospective studies simultaneously, and little is known about the association of severe sunburns at different body sites with skin cancer risk. We used data on 87,166 women in the Nurses' Health Study (1982-2010) and 32,959 men in the Health Professionals Follow-up Study (1992-2010) to investigate skin cancer risk associated with history of severe sunburns at different body sites (face/arms, trunk, and lower limbs). After adjustment for other risk factors, overall baseline history of severe sunburn was more apparently associated with risk of melanoma than with risk of SCC and BCC in men (multivariable-adjusted hazard ratios were 2.41 (95% confidence interval (CI): 1.32, 4.41) for melanoma, 1.48 (95% CI: 1.08, 2.03) for SCC, and 1.18 (95% CI: 1.06, 1.32) for BCC) but not in women. Sunburn on the trunk appeared to be more closely associated with melanoma risk, but not risk of SCC and BCC, when compared with sunburns at other body sites (face/arms and lower limbs). These differences were more apparent in men than in women. Pending further investigation, our findings add novel insights to the existing literature on sunburn history and skin cancer risk.

Nasal basal cell carcinomas. Can we reduce surgical margins to 3mm with complete excision?

BACKGROUND

The purpose of this study was to evaluate the incomplete excision rate of nasal basal cell carcinomas (BCC) resected with different margins to demonstrate that 3-mm surgical margins could be used as safety margins to reduce esthetic consequences with a low risk of incomplete excision.

METHODS

All patients with BCC of the nose excised from January 1st 2008 to December 31st 2011 were included. Data were analyzed and reviewed retrospectively. Tumors were treated with different surgical margins of excision: 3mm, 4mm, and 5mm. The primary outcome variable was the rate of incomplete excision. Other study variables were the histologic subtype, size, and recurrent lesions.

RESULTS

Of the 132 patients, 115 were included corresponding on with 127 BCC. Median age was 75.5 (64-83) and sex ratio M:F=1.05. Of the 127 BCC, 80 were aggressive histologic subtype (63%), and 11 were recurrent (8.7%). The overall rate of incomplete excision was 17.3% (n=22). Of these 22, 17 (77.3%) were of an aggressive subtype. The incomplete excision rates within the groups were 12.5% (n=4), 22.2% (n=10), and 16% (n=8), respectively within the group with 3-, 4- and 5-mm surgical margins. No significant difference was observed between the groups (P=.519). The incomplete excision rate was not independently associated with the surgical margins, histologic subtype and recurrent type (P>.05).

CONCLUSION

Three-millimeters margins could possibly be used to treat nasal BCC in chosen cases. Regarding the high rate of incomplete excision, reconstruction should be performed after receiving the pathologic report.

A Case-Control Study of Involvement of Oxidative DNA Damage and Alteration of Antioxidant Defense System in Patients with Basal Cell Carcinoma: Modulation by Tumor Removal

Oxidative damage has been suggested to play a role in the pathogenesis of basal cell carcinoma (BCC). This study illustrated an involvement of oxidative DNA damage and changes in antioxidant defenses in BCC by conducting a case-control study (24 controls and 24 BCC patients) and assessing urinary 7,8-dihydro-8-oxo-2′-deoxyguanosine (8-oxo-dGuo), plasma antioxidant defenses including catalase (CAT), glutathione peroxidase (GPx), NQO1, and total superoxide dismutase (SOD) activities, and glutathione (GSH) levels before surgery and 1 month after surgery. 8-oxo-dGuo expressions as well as protein and mRNA expressions of DNA repair enzyme hOGG1 and antioxidant defenses (CAT, GCLC, GPx, Nrf2, and MnSOD) in nonneoplastic epidermis of control and BCC tissues were also determined. This study observed induction in urinary 8-oxo-dGuo, increased 8-oxo-dGuo expression, and reduced hOGG1 protein and mRNA in BCC tissues, decreased activities of CAT, GPx, and NQO1, but elevated SOD activities and GSH levels in BCC patients and reduction of all antioxidant proteins and genes studied in BCC tissues. Furthermore, decreased plasma antioxidant activities in BCC patients were restored at 1 month after operation compared with preoperative levels. Herein, we concluded that BCC patients were associated with oxidative DNA damage and depletion of antioxidant defenses and surgical removal of BCC correlated with improved redox status.

Basal cell carcinoma of the skin (part 1): epidemiology, pathology and genetic syndromes

Basal cell carcinoma (BCC) is the most common skin cancer worldwide with increasing incidence, but difficult to assess due to the current under registration practice. Despite the low mortality rate, BCC is a cause of great morbidity and an economic burden to health services. There are several risk factors that increase the risk of BCC and partly explain its incidence. Low-penetrance susceptibility alleles, as well as genetic alterations in signaling pathways, namely SHH pathway, also contribute to the carcinogenesis. BCC associate with several genetic syndromes, of which basal cell nevus syndrome is the most common.

Non-melanoma Skin Cancer in Canada Chapter 4: Management of Basal Cell Carcinoma

Background

Basal cell carcinoma (BCC) is the most common malignancy. Growth of BCCs leads to local destruction of neighbouring healthy skin and underlying tissue and can result in significant functional and cosmetic morbidity.

Objective

To provide guidance to Canadian health care practitioners regarding management of BCCs.

Methods

Literature searches and development of graded recommendations were carried out as discussed in the accompanying Introduction.

Results

Although BCCs rarely metastasize“ they can be aggressive and disfiguring. This chapter describes the natural history and prognosis of BCCs. Risk stratification is based on clinical features” including the site and size of the tumour“ its histologic subtype (nodular vs sclerosing)” and its history of recurrence.

Conclusions

Various options should be considered for BCC treatment” including cryosurgery” curettage” and topical or photodynamic approaches, as well as fixed-margin surgery and Mohs micrographic surgery. Stratification of recurrence risk for individual BCCs determines the most appropriate therapeutic course.

Basal cell carcinomas on sun-protected vs. sun-exposed body sites: a comparison of phenotypic and environmental risk factors

BACKGROUND

Basal cell carcinoma (BCC) is the most commonly diagnosed cancer in White populations. There are indications that risk factors for BCC may differ according to the anatomic site of the tumour but this is not well understood.

PURPOSE

To compare phenotypic and environmental risk factors for BCCs arising on sun-protected sites with that of those on sun-exposed sites.

METHODS

We conducted a case-case study in which people who had been diagnosed with incident BCC were recruited between February 2012 and September 2013 in Brisbane, Australia.

RESULTS

Fair skin (OR: 4.50; 95% CI: 1.22, 16.59), having more than 15 lesions frozen/burnt off compared to less than 5 (OR: 5.68; 95% CI: 1.78, 18.08) and severe acne (OR: 5.25; 95% CI: 1.34, 20.56) were associated with increased risk of BCC on sun-protected sites. The presence of more than 5 nevi on the body was associated with decreased risk (OR: 0.28; 95% CI: 0.11, 0.71).

CONCLUSIONS

BCCs on sun-protected sites arise as a result of excessive sun exposure, most likely combined with phenotypic susceptibility. The strong negative association with nevi also suggests that there are constitutional factors that underlie the propensity for BCCs to arise on these body sites.

The consequences for human health of stratospheric ozone depletion in association with other environmental factors

Ozone depletion, climate and human health.

Cumulative ultraviolet radiation flux in adulthood and risk of incident skin cancers in women

BACKGROUND

Solar ultraviolet (UV) exposure estimated based on residential history has been used as a sun exposure indicator in previous case-control and descriptive studies. However, the associations of cumulative UV exposure based on residential history with different skin cancers, including melanoma, squamous cell carcinoma (SCC), and basal cell carcinoma (BCC), have not been evaluated simultaneously in prospective studies.

METHODS

We conducted a cohort study among 108,578 women in the Nurses' Health Study (1976-2006) to evaluate the relative risks of skin cancers with cumulative UV flux based on residential history in adulthood.

RESULTS

Risk of SCC and BCC was significantly lower for women in lower quintiles vs the highest quintile of cumulative UV flux (both P for trend <0.0001). The association between cumulative UV flux and risk of melanoma did not reach statistical significance. However, risk of melanoma appeared to be lower among women in lower quintiles vs the highest quintile of cumulative UV flux in lag analyses with 2-10 years between exposure and outcome. The multivariable-adjusted hazard ratios per 200 × 10(-4) Robertson-Berger units increase in cumulative UV flux were 0.979 (95% confidence interval (CI): 0.933, 1.028) for melanoma, 1.072 (95% CI: 1.041, 1.103) for SCC, and 1.043 (95% CI: 1.034, 1.052) for BCC.

CONCLUSIONS

Associations with cumulative UV exposure in adulthood among women differed for melanoma, SCC, and BCC, suggesting a potential variable role of UV radiation in adulthood in the carcinogenesis of the three major skin cancers.

A young military pilot presents with a periocular Basal Cell Carcinoma: a case report

INTRODUCTION

Basal Cell Carcinoma (BCC) is the most common form of skin malignancy in the UK with 75, 000 new cases per year. It commonly presents as a non-healing lesion in the H zone of the face. The significant risk factors for this condition include UV radiation exposure and a history of sunburn. The gold standard treatment for BCC is Mohs Micrographic Surgery as well a variety of traditional surgical and non-surgical options.

CASE PRESENTATION

A 32 year old white male military helicopter pilot presented with a pea sized lesion which appeared highly vascularised with multiple telangiectasia on the surface. The main risk factors were regular foreign travel to regions of high UV radiation and previous episodes of sunburn.

CONCLUSION

BCC is the commonest form of eye lid malignancy and any form of non-healing lesion on the periocular area should be investigated as a possible neoplasm. The main risk factors are travel to areas of high UV radiation and exposure to UV radiation as a child. There is also a possible risk factor of occupational exposure to ionising radiation from cosmic sources although there is limited research to support this. This is an interesting case of an unusual first presentation of a BCC in a male under 40 years of age and demonstrates the important risk factors in a military population for developing a non-melanoma skin cancer.

Cutaneous squamous cell carcinomas of the lower extremity: a distinct subset of squamous cell carcinomas

BACKGROUND

Some patients develop a disproportionate number of cutaneous squamous cell carcinomas (SCCs) on their lower extremity (LE).

OBJECTIVE

We sought to characterize the clinical features, treatment, and outcome in patients who develop multiple LE SCCs.

METHODS

We identified 22 patients with 4 or more biopsy-diagnosed LE SCCs during a 4.5-year study period. The location, size, treatment, and clinical outcome of each LE SCC were recorded.

RESULTS

Of the 22 patients studied, 18 were female. Of the 360 SCCs our patients developed, 260 (72.2%) were on the LE. The incidence of SCCs in these patients was nearly 7 times greater than the incidence of basal cell carcinoma in the same patients.

LIMITATIONS

The number of patients is small and limits definitive conclusions about prevalence of SCCs on the LE in the general population.

CONCLUSIONS

LE SCCs are a distinct subset of cutaneous SCCs and may have distinctive clinical features and biologic behavior requiring additional study.