Thousands of Canadian women in their 40s may have died needlessly from breast cancer due to a lack of access to mammographies as a result of two “skewed” studies that informed guidelines recommending against screening for this age group, a team of researchers says. In a commentary published in the Journal of Medical Screening on Nov. 23, researchers from five universities said they have new evidence that the Canadian National Breast Screening Study trials conducted in the 1980s were not randomized properly, leading to unreliable results.  Results at the time found that routine mammograms did not reduce deaths in women aged 40 to 49. A second trial involving women from 50 to 59 was also carried out with similar results.  The researchers from the University of Toronto, University of Ottawa, University of British Columbia, University of Alberta, and Harvard Medical School said they are concerned about “serious errors in trial …