SUMMARY: It is estimated that in the US, about 87,110 new cases of melanoma will be diagnosed in 2017 and about 9,730 patients will die of the disease. The incidence of melanoma has been on the rise for the past three decades. Alcohol related cancers account for 5.8% of all cancer deaths worldwide and there is compelling epidemiological evidence supporting that alcohol causes cancer of the oropharynx, larynx, oesophagus, liver, colon, rectum and breast (seven sites).
The mechanism of alcohol related carcinogenesis is not well understood and may vary from each target organ. Alcohol is predominantly metabolized in the liver to acetaldehyde, which is a carcinogen. Acetaldehyde is then converted into acetic acid radicals also known as acetyl radicals. There is strong evidence to suggest that acetaldehyde damages DNA. This mechanism of alcohol related carcinogenesis has been implicated in cancer of the oropharynx, larynx, esophagus and liver. With regards to breast cancer, breast tissue may be more susceptible to alcohol than other sites. Even moderate alcohol intake has been associated with increased levels of circulating sex hormones which in turn can activate cellular proliferation.
Even though the association between alcohol consumption and increased risk of numerous cancers is well known, there has been little or no evidence to associate alcohol consumption to melanoma. The authors in this study investigated whether alcohol intake was associated with risk of melanoma, by using data from three large prospective cohort studies, which included 210,252 participants. These individuals were followed for a mean of 18.3 years. The participants responded to questionnaires approximately every 4 years from 1984 to 2007 and provided information on their alcohol intake. A standard drink was defined at 12.8 grams of alcohol (one drink is considered to be 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of hard liquor).
In this pooled analysis, a total of 1,374 cases of invasive melanoma were documented during the follow up period. Higher alcohol intake was associated with an increased incidence of invasive melanoma (HR=1.14; P=0.04). When analyzed by the type of alcoholic beverages and after adjusting for other alcoholic beverages, white wine consumption was associated with an increased risk of melanoma (HR 1.13; P<0.01). It was also noted that alcohol consumption-related melanoma risk, was higher in the UV-spared sites such as the torso which receives less sun exposure, compared with UV-exposed sites such as head, neck, or extremities. Individuals who consumed 20 grams or more of alcohol a day were 73% more likely to be diagnosed with melanomas of the trunk compared to nondrinkers (HR=1.3;P=0.02), whereas only 2% of the individuals were more likely to be diagnosed with melanoma of the head, neck and extremities compared with non drinkers (HR=1.02; P=0.25).
The researchers noted that there was no evidence that age, smoking history, caffeine intake, physical activity, hair color, mole count or BMI, modified the association between alcohol intake and melanoma, when these results were stratified by those variables. It was hypothesized that white wine may have higher levels of pre-existing acetaldehyde (which gives the pleasant fruity aroma), than beer or hard liquors and the antioxidants in the red wine may offset the carcinogenic risks associated with acetaldehyde.
The authors concluded that these findings support the American Cancer Society Guidelines for Cancer Prevention, to limit alcohol intake, and alcohol consumption was associated with a modest increase in the risk of melanoma, particularly on parts of the body that are less sun exposed. Alcohol Intake and Risk of Incident Melanoma: A Pooled Analysis of Three Prospective Studies in the United States. Rivera A, Nan H, Li T, et al. Cancer Epidemiol Biomarkers Prev. 2016;25:1550-1558