So, the two groups being compared may have been significantly different at the start in ways that can not be measured using retrospective data. (sciencemediacentre.org)
The 15 - year study is designed to collect retrospective data at enrollment, and participants will then be followed prospectively every six months. (hivresearch.org)
«Although this study is based on retrospective data with much detailed data, and residual confounding factors can not be ruled out completely, we believe that this information will have potential to greatly improve shared treatment decision - making for future breast cancer patients in those aged over 50 years and those with comorbidity,» says Prof Siesling. (sciencedaily.com)