The role of the radiation therapy breast boost in the 2020s
Given that most local relapses of breast cancer occur proximal to the original location of the primary, the delivery of additional radiation dose to breast tissue that contained the original primary cancer (known as a “boost”) has been a standard of care for some decades. In the context of falling relapse rates, however, it is an appropriate time to re-evaluate the role of the boost. This article reviews the evolution of the radiotherapy boost in breast cancer, discussing who to boost and how to boost in the 2020s, and arguing that, in both cases, less is more.
Delivery of additional dose to the region of breast tissue proximal to the original breast primary has a sound clinicopathological basis. In the context of falling local relapse rates, and in the absence of a survival advantage, the proportion of patients requiring a tumour bed boost should also be falling (with key suggested eligibility criteria including young age, high grade and triple negative phenotype). Where a boost is delivered, the target volume and treatment burden should be minimised for example using clip-defined simultaneous integrated photon boosts or brachytherapy, ideally delivering treatment over no more than 3–4 weeks to minimise the treatment burden for the patient and for health economies.