Sequencing of chemotherapy and radiotherapy for women following surgery for early breast cancer

Both chemotherapy and radiotherapy reduce the risk of breast cancer recurring and the risk of dying from breast cancer. Generally these therapies are given after surgery but there is uncertainty about whether they should be given at the same time (concurrently) or one after the other (sequentially). If they are used sequentially, the radiotherapy or the chemotherapy could be used first and concerns have been expressed that the effectiveness of the therapy that is delayed might be reduced. However, it has also been suggested that using chemotherapy and radiotherapy at the same time will be less beneficial than keeping them separate. This review examined current evidence on the best way to administer chemotherapy and radiotherapy following breast conserving surgery. We were able to include three randomised trials. Two of these, with a total of 853 women, assessed radiotherapy and chemotherapy given at the same time versus chemotherapy given first followed by radiotherapy. The third trial randomised 244 women to radiotherapy followed by chemotherapy versus chemotherapy followed by radiotherapy. The evidence produced by these three well conducted trials suggests that recurrence of a woman's cancer and her chances of dying from breast cancer are similar regardless of the order of the treatments, provided that both radiotherapy and chemotherapy are commenced within seven months of the surgery. The trials provided limited information regarding adverse events, side effects, or quality of life associated with the different sequences of treatment, but the limited evidence available does suggest that the frequency and severity of side effects of chemotherapy and radiotherapy are similar regardless of which sequence is used. It should be noted, however, that the women in these trials were treated, on average, ten years ago. As a result the trials do not assess the modern types of radiotherapy, and newer types of chemotherapy (such as taxanes) or other drugs (such as Herceptin). We will add relevant trials which include these newer treatments to future updates of this review.