Distress is a factor that can adversely affect quality of life in breast cancer patients. A rapid and non-invasive tool to accurately detect distress is therefore important. The aims of the study were (1) to describe the women's experiences after having received a breast cancer diagnosis and while awaiting primary surgery, in terms of anxiety and depression, (2) to evaluate the use of the Distress Thermometer (DT) in newly diagnosed breast cancer patients, and (3) to define an optimal cutoff score for the DT for this population.