Abstract ES5-1: Emerging Radiation Techniques — The Fast and the Furious

Abstract

Abstract The equivalence of breast conserving therapy (BCT) to mastectomy in the treatment of women with early-stage breast cancer has been demonstrated in several phase III trials with over 25 years of follow-up. Despite the undisputed efficacy of this treatment approach, recent investigations have explored methods to either reduce the overall time, inconvenience or toxicity of its application. These approaches have included (1) accelerating the dose delivery scheme, (2) reducing the treatment target to less than whole breast, or (3) identifying subgroups of women in which adjuvant radiation therapy (RT) following lumpectomy can be safely omitted Accelerated partial breast irradiation (APBI) has been investigated as a possible option that incorporates both a decrease in the overall treatment time and a reduction in the amount of normal tissue irradiated. Several different treatment techniques have been developed for the delivery of APBI. Within the United States, three ‘classic’ techniques dominate and include multicatheter interstitial brachytherapy, balloon catheter brachytherapy and three-dimensional conformal external beam radiotherapy (3D-CRT). In Europe, in addition to multicatheter brachytherapy, intraoperative radiotherapy has been central to their APBI experience. The majority of results with APBI to date have provided comparable 5 and 10-year outcomes to whole breast irradiation (WBI) in highly selected, low risk patients. In recognition of the success of these single institution experiences, nine phase III studies have now been initiated or completed in the United States and Europe. Despite limited long-term clinical data, the use of APBI outside of clinical trials has increased sharply. Given these concerns, the American Society of Therapeutic Radiology and Oncology (ASTRO) Health Services Research Committee convened a Task Force of breast cancer experts to develop a consensus statement addressing patient selection criteria and best practices for the application of APBI outside of clinical trials. These recently published recommendations were based on the results of a systematic literature review of the limited APBI data and were also supplemented by the expert opinions of the Task Force members using data applying WBI to treat patients. Accelerated whole breast irradiation (AWBI) has also been explored as a potential treatment option to deliver adjuvant irradiation after lumpectomy. Similar to APBI, the goals of this treatment approach are to theoretically increase the frequency that BCT is chosen as a treatment option, provide a logistically faster, convenient and more accessible method for BCT and potentially improve overall quality-of-life for early stage breast cancer patients. The data on AWBI include several phase III trials performed in Europe and North America with some trials reporting results at 10 years. In recognition of the concerns related to appropriate selection criteria for the application of this treatment approach, the ASTRO Health Services Research Committee also convened a Task Force of breast cancer experts to develop a consensus statement addressing patient selection criteria and best practices for the application of AWBI. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr ES5-1.