The purpose of arimidex (an other aromatase inhibitors)
is to try to prevent cancer recurrence – not only
for the duration that the drug
is used but in years beyond. The purpose of the clinical trial is to ask the question if 10 years is better than 5. While there are recurrences in people who are taking arimidex and other medications, the data is looked at not individually but in large numbers to see if overall, 10 years would be better than 5.