Second, it should be noted that breast cancer incidence rates are not increasing, and mortality rates have been decreasing in all age groups over the last two decades as result of improved treatment.
Writing in the Lancet, Professor Martin Schrappe of the University Medical Centre Schleswig-Holstein said the 20% difference seen between the twogroups was "one of the largest improvements ever achieved by a single modification of treatment".
This study randomly divided patients into twogroups - one received the antibiotic and the other was given a placebo, an inert treatment in the form of a sugar pill, three times a day for seven days.