Questions still swirl about alcohol and cancer risk.
While head and neck cancers, esophageal cancer, liver cancer, breast cancer, colon cancer, and rectal cancer have the clearest associations with alcohol consumption, a new study suggests that melanoma could join the ranks.
The link between drinking alcohol and developing cancer has been well studied. In the United States, alcohol consumption is associated with approximately 3% of cancer deaths, and alcohol itself is classified as a known human carcinogen by the Department of Health and Human Services.
But the study, published in the journal Cancer Epidemiology, Biomarkers & Prevention, asserted that alcohol intake was associated with a “modest increased risk” of melanoma. This conclusion is confounding, though, says Bhuvanesh Singh, Director of the Laboratory of Epithelial Cancer Biology at MSK, adding that more research should be conducted.
We spoke with Dr. Singh and Irene Orlow, a scientist who leads the Molecular Epidemiology Laboratory at MSK, to learn more about the relationship between alcohol and cancer and to put the findings from this particular study into context.
The Risk of Developing Melanoma
This analysis, which looked at 210,252 individuals prospectively, showed a greater association between alcohol consumption and melanoma in women compared with men. Dr. Singh points out that only white individuals were studied, and women in this group were more likely to have a family history of melanoma and red or blonde hair, which also raises skin cancer risk.
These individuals — who are at higher risk of developing melanoma regardless of alcohol consumption — should have their skin screened regularly and should practice safe sun behavior, Dr. Singh says. Regarding alcohol consumption, he says, the study data is not clear enough for him to recommend additional precautionary measures beyond advising moderate consumption.
“I am not sure that the data presented here are sufficient to warrant a change in general health recommendations,” he adds. “Given the known detrimental effects of alcohol use, however, moderation is always recommended.”
Location, Location, Location
Another key conclusion drawn by the study authors, who hailed from Brown University, Harvard Medical School, and Indiana University, was that the “association between alcohol and melanoma was strongest for parts of the body that typically receive less sun exposure.” The authors argued that the effect of alcohol consumption on the risk of developing melanoma may be independent from sun exposure.
But this, too, cannot be concluded definitively, says Dr. Singh. He points out that though the study showed a greater association of alcohol consumption and melanoma risk in women, the risk of melanoma on an area of the body that typically receives less sun exposure — the trunk — was more strongly seen in men. In women, melanoma risk was still higher for the head, neck, and extremities.
Dr. Singh says this information confirms a well-known fact: that melanoma risk is related to sun exposure.
Though the authors took into consideration UV-B exposure, additional sun exposure is still possible, Dr. Orlow argues. Future studies should include a more robust and comprehensive measurement of each individual’s sun exposure.
Grape Expectations
The study authors categorized individuals into one of five groups based on the number of alcoholic drinks they consumed per week. Their study concluded that the risk of melanoma increased by 14% with each drink per day.
But the quantity of alcohol consumed is a more complex question, Dr. Orlow says. “The potential carcinogenic effect depends not only on consumption, also on the individual’s metabolism.”
In a related commentary, one of the study’s authors singled out white wine as “the only drink independently associated with increased risk of melanoma.” She added that it’s possible that higher levels of acetaldehyde — an organic chemical compound found in both red and white wine as well as in beer or spirits, but at lower levels — could be a contributing factor to the increased risk. Antioxidants in red wine offset that risk, making white wine the greater offender.
Dr. Singh asserts that this hypothesis is getting ahead of what the data actually showed. He says that it’s unknown what type of white wine the individuals drank and, frankly, it could just be a statistical anomaly.
The Bottom Line
Dr. Orlow says the knowledge of alcohol as a carcinogen seems to be following a similar path as smoking tobacco. It was once a common belief that smoking was associated only with lung cancer, Dr. Orlow says. But the medical community has learned — through well-designed research — that smoking is strongly associated with head and neck cancers, kidney cancer, colon cancer, and bladder cancer, among others.
We’ve also learned in recent years that alcohol consumption is related to other cancers beyond those of the head and neck, Dr. Orlow says. She adds that also, not all melanomas can be attributed to sun exposure. There needs to be more research into how the remaining melanomas are caused.
“Alcohol consumption has been associated with the development of many different types of cancers — and several other medical issues — and it is probably best to consume it in moderation,” Dr. Singh reiterates. “Whether the association is stronger with melanoma as well remains to be seen.”
