Thanks for the question.
A number of things went on, including a randomized controlled trial, which is supposed to be the gold standard. There were issues with that randomization. There are papers that have shown that to be the case. There were other issues as well as that non-randomization.
Of course, one of the main things, even if the study was equal and perfect, was the fact that they used 98% white women—Dr. Narod agreed in the House of Commons last time—when we know that this is not reflective of the Canadian population today.