A drink of alcohol a day increases the risk of breast cancer in women of all ages and also causes other cancers

See:  https://www.cancer.gov/about-cancer/causes-prevention/risk/alcohol/alcohol-fact-sheet

The following is taken directly from the National Cancer Institute website.

     Clear patterns have emerged between alcohol consumption and the development of the following types of cancer:

• Esophageal cancer: Alcohol consumption is a major risk factor for a particular type of esophageal cancer called esophageal squamous cell carcinoma (2). In addition, people who inherit a deficiency in an enzymethat metabolizes alcohol have been found to have substantially increased risks of alcohol-related esophageal squamous cell carcinoma.

• Liver cancer: Alcohol consumption is an independent risk factor for, and a primary cause of, liver cancer (hepatocellular carcinoma) (6). (Chronic infection with hepatitis B virus and hepatitis C virus are the other major causes of liver cancer.)

• Breast cancer: More than 100 epidemiologic studies have looked at the association between alcohol consumption and the risk of breast cancer in women. These studies have consistently found an increased risk of breast cancer associated with increasing alcohol intake. A meta-analysis of 53 of these studies (which included a total of 58,000 women with breast cancer) showed that women who drank more than 45 grams of alcohol per day (approximately three drinks) had 1.5 times the risk of developing breast cancer as nondrinkers (a modestly increased risk) (7). The risk of breast cancer was higher across all levels of alcohol intake: for every 10 grams of alcohol consumed per day (slightly less than one drink), researchers observed a small (7 percent) increase in the risk of breast cancer.

The Million Women Study in the United Kingdom (which included more than 28,000 women with breast cancer) provided a more recent, and slightly higher, estimate of breast cancer risk at low to moderate levels of alcohol consumption: every 10 grams of alcohol consumed per day was associated with a 12 percent increase in the risk of breast cancer (8).

• Colorectal cancer: Alcohol consumption is associated with a modestly increased risk of cancers of the colon and rectum. A meta-analysis of 57 cohort and case-control studies that examined the association between alcohol consumption and colorectal cancer risk showed that people who regularly drank 50 or more grams of alcohol per day (approximately 3.5 drinks) had 1.5 times the risk of developing colorectal cancer as nondrinkers or occasional drinkers (9). For every 10 grams of alcohol consumed per day, there was a small (7 percent) increase in the risk of colorectal cancer.
• Research on alcohol consumption and other cancers:Numerous studies have examined the association between alcohol consumption and the risk of other cancers, including cancers of the pancreas, ovary, prostate, stomach, uterus, and bladder. For these cancers, either no association with alcohol use has been found or the evidence for an association is inconsistent.However, for two cancers—renal cell (kidney) cancer and non-Hodgkin lymphoma (NHL)—multiple studies have shown that increased alcohol consumption is associated with a decreased risk of cancer (10, 11). A meta-analysis of the NHL studies (which included 18,759 people with NHL) found a 15 percent lower risk of NHL among alcohol drinkers compared with nondrinkers (11). The mechanisms by which alcohol consumption would decrease the risks of either renal cell cancer or NHL are not understood.