Women who have had breast cancer should stick to three alcoholic drinks or less a week to reduce the chance of the disease returning, researchers suggest.
Breast cancer is the most common cancer in the UK
A US study of 1,900 women who had recovered from breast cancer found that moderate drinking was linked to a 30% higher risk of recurrence.
The eight-year study found the strongest link in women who were post-menopausal or overweight.
UK charities said alcohol is known to increase the risk of cancer in general.
Presenting the research at the American Association for Cancer Research breast cancer conference, the researchers said few studies had been done on the risk of alcohol consumption and the recurrence of cancer.
The study looked at women diagnosed with breast cancer between 1997 and 2000, and compared recurrence of the disease in those who drank alcohol with those who abstained.
Over the course of the research there were 349 breast cancer recurrences.
The increased risk found in those who drank at least three to four drinks a week was apparent regardless of the type of alcohol drunk.
But alcohol consumption was not associated with overall mortality.
Study leader Dr Marilyn Kwan, from the Kaiser Permanente Division of Research in Oakland, California, said other studies were needed to check the validity of the findings.
But she added: "These results can help women make more informed decisions about lifestyle choices after a diagnosis of breast cancer.
"Women previously diagnosed with breast cancer should consider limiting their consumption of alcohol to less than three drinks per week, especially women who are postmenopausal and overweight or obese."
Dr Caitlin Palframan, policy manager at Breakthrough Breast Cancer, said it would advise women to be aware of how much alcohol they consumed and to drink in moderation.
"We already know that regularly drinking alcohol can increase a woman's chances of developing breast cancer.
"This study may suggest that alcohol consumption could also play a role in the likelihood of the disease coming back.
"The good news is that alcohol consumption is something we can change."
Dr Jodie Moffat, health information manager at Cancer Research UK, said: "It's important to understand the things that influence the odds of breast cancer returning, but as yet we can't say for sure that alcohol plays a part in this.
"We already know that alcohol increases the chances of developing several different types of cancer, including breast cancer - so cutting down on alcohol is certainly an important thing people can do to reduce their cancer risk."