Even moderate drinking increases the risk of breast cancer, according to the American Society of Clinical Oncology (ASCO). Moderate drinking — up to one drink a day for women and two for men — carries a 23 percent increased risk of breast cancer and 17 percent increased risk of colon cancer, the group said in a statement published in the Journal of Clinical Oncology.
“The message is not, ‘Don’t drink.’ It’s, ‘If you want to reduce your cancer risk, drink less. And if you don’t drink, don’t start,’” said Dr. Noelle LoConte, an associate professor at the University of Wisconsin-Madison and the lead author of the ASCO statement. “It’s different than tobacco where we say, ‘Never smoke. Don’t start.’ This is a little more subtle.”
The ASCO cites evidence that even light drinking can slightly raise a woman’s risk of breast cancer and increase a common type of esophageal cancer.
Heavy drinkers face much higher risks of mouth and throat cancer, cancer of the voice box, liver cancer and, to a lesser extent, colorectal cancers, the group cautions.
At least three drinks daily or eight weekly for women, and at least four daily or 15 weekly for men, increases the risk of head, neck and throat cancers five-fold, the ASCO said. Heavy drinking also more than doubles the chance of getting liver and voice box cancer.
Overall, 5.5 percent of all new cancers and 5.8 percent of all cancer deaths worldwide could be attributed to alcohol, the doctors said.
The oncology society called attention to the long-established link between alcohol and cancer after a survey last month said 70 percent of Americans didn’t know drinking was a risk factor for cancer.
The group also encouraged policy changes, such as increasing alcohol taxes, enhancing enforcement of laws banning sales to minors and eliminating “pink washing” — companies using pink ribbons or the color pink, associated with breast cancer awareness, to boost alcohol sales.
“It’s sort of like selling cigarettes to raise awareness for lung cancer,” LoConte said.
Alcohol is thought to increase the risk of head, neck, throat and voice box cancers because those tissues come into direct contact with alcohol when people drink, according to the ASCO.
One way alcohol may lead to cancer is because the body metabolizes it into acetaldehyde, which causes changes and mutations in DNA, according to the doctors. The formation of acetaldehyde starts when alcohol comes in contact with bacteria in the mouth, which may explain the link between alcohol and cancers of the throat.
Alcohol may also increase the amount of estrogen in the blood, which could explain the link to breast cancer.
Some studies have suggested that alcohol, notably red wine, can lower the risk of heart disease. But further analysis said the non-drinkers studied often had other health problems, making the drinkers only appear to be healthier, the oncology society said.
Among all cancers, head and neck cancers are somewhat common, with about 50,000 cases and 10,000 deaths expected this year, according to the American Cancer Society.
Esophagus, or throat, cancer is more unusual but considerably deadly, with about 17,000 cases and 16,000 deaths this year.
About 255,000 people will be diagnosed this year with breast cancer, and 41,000 will die, and about 96,000 will get colon cancer, with about 50,000 deaths.
If people exercise, eat well and don’t drink excessively, they shouldn’t worry too much, said LoConte, who said she has about two drinks a month.
“Life as an oncologist is all about teaching people about moderation,” she said.
