While the drug tamoxifen reduces the risk of developing breast cancer and prevents recurrence, the side-effects cause many women to discontinue their treatment. A study involving researchers at Karolinska Institutet in Stockholm has now found that a much lower dose than the standard produces a good effect with fewer adverse reactions in women who have yet to enter the menopause. The study, which has been published in the Journal of Clinical Oncology, can play a significant role in the treatment of cancer.