There is an almost uncontested link between alcohol consumption and cancer, recognised by the World Cancer Research Fund, and now confirmed in further research published in the British Medical Journal (April 2011), and a recent Catalan Institute of Oncology in Barcelona study linking alcohol consumption drinking to stomach cancer in particular.

The research links alcohol consumption to many types of cancer. The World Cancer Research Fund 2007 report into diet and cancer gives very clear advice.
The evidence on cancer justifies a recommendation not to drink alcoholic drinks. The evidence shows that all alcoholic drinks have the same effect. Data do not suggest any significant difference depending on the type of drink. This recommendation therefore covers all alcoholic drinks, whether beers, wines, spirits (liquors), or other alcoholic drinks.
In 2007 The Lancet published a report on the link between alcohol and disease and "identified the consumption of alcohol as one of the top-10 risks for worldwide burden of disease". It continues:

Many studies of different design and in different populations around the world have consistently shown that regular alcohol consumption is associated with an increased risk for cancers of the oral cavity, pharynx, larynx, and oesophagus. Daily consumption of around 50 g of alcohol increases the risk for these cancers by two to three times, compared with the risk in non-drinkers.
In it's 2007 study The International Agency for Research on Cancer added to the list of cancers already related to alcohol (oral cavity, pharynx, larynx, oesophagus, and liver cancer) with two of the most common cancers—female breast and colorectal cancer.

Now (April 2011) major European research published in the British Medical Journal reports on 520,000 people from 10 countries and quantifies further the now well established link between alcohol consumption and cancer. The EPIC (European Prospective Investigation into Cancer and Nutrition) research shows that 10 per cent of cancers in men and 3 per cent of cancers in women are linked to alcohol consumption.

As the study concludes:
"Alcohol has long been thought to account for a substantial number of deaths worldwide, with Europe and America showing the highest alcohol attributable fractions of 6.5% and 5.6%, respectively. Chronic diseases, especially cancer, contribute markedly to this burden".
The report's recommendations are straightforward:
"A considerable proportion of the most common and most lethal cancers is attributable to former and current alcohol consumption, especially to consumption above the recommended upper limit. This strongly underlines the necessity to continue and to increase efforts to reduce alcohol consumption in Europe, both on the individual and the population level.

In a study conducted by the Catalan Institute of Oncology in Barcelona  (discussed on the Health Tree website) researchers analyzed stomach cancer records of 521,000 people, checking alcohol consumption against severity of cancer.  Those who drank 60 grams of alcohol a day were 65 percent more likely to suffer from stomach cancer, and beer drinkers were 10 percent more likely again.  In summary, people who drink two to three beers a day increase their chance of getting stomach cancer by 75 percent .