In Reply: Most of the points made in Dr Kopans' letter were also made in our article. We pointed out that the imbalance of the 19 women in the mammography group vs 5 in the control group suggested a problem with randomization.
We pointed out that the initial trials were never intended to permit subset analysis of women aged 40 to 49 years, and thus the 12 policy groups appropriately initially recommended screening in the age groups covered by the clinical trials.