The cancer effects of alcohol intake are poorly quantified and understood. In a study published in 2019, the authors comment that there is no lower limit of safe alcohol consumption for health.1
Alcohol is associated with carcinoma of the oropharynx, larynx, oesophagus, colorectum, liver and breast.
Using UK data the authors calculated that one bottle of wine per week was equivalent to 5 cigarettes per week for men and 10 cigarettes for women. The increased risk for women is due to the effect of breast cancer, with men at much lower risk for this.
The authors state that drinking alcohol in moderation is in no way equivalent to smoking. Smoking kills up to two-thirds of its users, with cancer just one of the many serious health consequences. This study purely addresses cancer risk in isolation.