While cigarette smoking has decreased in recent years, the use of e-cigarettes has only grown. But what are e-cigarettes associated risks for non-melanoma skin cancer? A recent study aims to find out.
The incidence and prevalence of non-melanoma skin cancer including basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) have increased in the United States from 1990 to 2019.1 Despite this alarming fact, the rising incidence may be even greater than estimated because it is not a requirement for physicians to report non-melanoma skin cancer (NMSC) to national cancer registries.
While NMSC incidence is increasing, cigarette smoking among American adults has declined in recent years.2 However, electronic cigarettes (e-cigarettes) sales have continued to increase in the country, with 6.7% of adults reporting current use. Simultaneously, e-cigarettes are becoming the most commonly used tobacco product among youth in the United States.3,4
One reason for this recent spike in popularity is that e-cigarettes claim to be a healthier alternative to traditional cigarettes given that they may have fewer toxic substances. Moreover, e-cigarette companies have rapidly increased their advertising expenditures from $6.4 Million to $115 Million in just 3 years and are using themes targeted at youths including sex, independence, and rebellion in their marketing materials.5 Even more alarming is that about 70% of middle school and high school students have been exposed to e-cigarette advertisements through stores, magazines, TV and the internet.5 E-cigarettes and their delivered toxins appear to be harmful to various organ systems including the cardiovascular system, the respiratory system, and the immune system.6 While vapor from e-cigarettes has been shown to be toxic to human skin cells, a paucity of research has investigated the affect of its use on NMSC.7
To help answer this question, Dugan et al. analyzed data collected from the National Health Interview Survey (NHIS) with the goal of assessing whether a relationship exists between e-cigarette use and the diagnosis of NMSC.8 The NHIS is a household survey conducted every year to collect health information about the US population but excludes certain populations such as individuals living in long term care facilities. For this particular study, data from 2014 to 2018 were analyzed while establishing a control group of participants who reported never being diagnosed with any type of cancer. The questionnaire included standard demographic data along with questions about prior cancer diagnoses and exposures to cigarettes and e-cigarettes. To determine the use of e-cigarettes, responses to “ever used electronic cigarettes” were used, and to determine the use of combustible cigarettes, responses to “smoked 100 cigarettes” were used. Cigarette use, sex, and age were controlled for by the use of a multivariate model.
“E-cigarettes have become widely popular in a short period of time. Despite the rapid acceptance of e-cigarettes as an alternative, it still remains unclear what the long-term effects are on the skin,” said Jonathan Soh, MD, who is a board-certified dermatologist, mohs surgeon, and skin cancer specialist in private practice in Chevy Chase, Maryland.
The study authors included data from 155,556 participants. About 2% of participants reported a diagnosis of NMSC with a mean age for diagnosis at 67 years of age. Among the cohort who reported a positive history of NMSC, about half reported having smoked at least 100 cigarettes, and 7.2% reported engaging in the use of e-cigarettes at least once. Of those never diagnosed with any type of cancer, 38.8% reported having smoked at least 100 cigarettes, and 14.4% reported having used an electronic cigarette at least one time.
They found males and those of older age were significantly more likely to be diagnosed with NMSC compared to women and younger adults. Cigarette use was significantly associated with an increased risk of NMSC, but the authors failed to find a relationship between e-cigarettes and the diagnosis of NMSC. “While the authors did not find a significant relationship between e-cigarette use and NMSC, it is plausible that unknown [adverse effects] may be discovered in the coming years,” Soh said.
Almost all patients diagnosed with NMSC in this study were Caucasian and non-Hispanic which is consistent with another study which found that 96.3% of non-melanoma skin cancer cases were among Caucasians and 2.9% of cases were among Hispanic Americans.9 The study found that males had an increased risk of being diagnosed with NMSC. However, when examining smoking and gender, Song et. al found that gender influenced cancer risk amongst smokers, where men were suggested to have a lesser risk of BCC while women had a higher risk of BCC compared to nonsmokers.10 Despite these potentially relevant findings, the authors did not analyze the gender risk regarding smoking status or type of NMSC diagnosed. Sub-analyses, such as gender risk, are important in these types of studies because it allows physicians to counsel patients more effectively regarding their individual risk based on characteristics such as age, genetics, and ethnicity, he said.
The current study implies combustible cigarette use may be a risk factor for developing NMSC. These results are partially consistent with the results of a meta-analysis in JAMA Dermatology which suggested smoking can increase the risk for developing SCC but has no impact on the risk BCC.11
While this study failed to find a significant relationship between e-cigarette use and skin cancer, e-cigarettes still pose a risk of cutaneous disease and cutaneous injury. One review study demonstrated that e-cigarettes can lead to contact dermatitis, thermal injury, hyperplastic candidiasis, nicotine stomatitis, and other oral mucosal lesions.12
While the main research question was not answered, a longer study period and larger sample is necessary to better determine if a significant relationship exists between e-cigarette use and NMSC. Limitations of the current study included recall bias, the lack of information regarding the precise amount of e-cigarette use, and given the recent popularity of e-cigarettes, more time may be needed before a significant relationship is apparent. Significant results could be found after patients experience longer and more sustained exposures to e-cigarettes and their resulting toxins. Therefore, more research is needed to better understand the deleterious health effects of e-cigarette use, especially its effect on the skin. “This will be an interesting topic in epidemiology to track and follow up on”, Soh concluded.