Typically, following a lumpectomy for breast cancer, patients receive radiotherapy (RT) to the breast to reduce the chance of cancer recurring in the breast. This is now often given in five daily treatments (called fractions) over one week based on the results of a large study from the UK which showed this approach was safe and effective.
There are, however, some patients with cancers that are at increased risk of recurrence after lumpectomy. They need a higher dose of RT called a “boost” to the tumour cavity after surgery. Typically, this boost is given with five to eight additional daily treatments over one to two weeks “sequentially,” after the whole breast RT of one week. This boost treatment can potentially also be given at the same time as the whole breast RT, using advances in radiation planning to give a higher dose to the tumour bed on each of the five days of treatment, called “simultaneous integrated boost” (SIB). This would shorten treatment by one to two weeks and allow for improved patient convenience, reduced costs to patients and the healthcare system, and potentially fewer side effects.
This is a pilot study of SIB to the tumour bed delivered together with the typical five-fraction treatment to the whole breast, for five treatments total. The pilot study will provide preliminary data to facilitate the planning of a larger trial comparing SIB to the longer “sequential” boost approach to breast RT, and collect data on toxicity, and cosmetic outcome and local recurrence.
