A multicentre feasibility study of partial breast irradiation using 3D conformal radiotherapy for early breast cancer

对于大多数患有早期乳腺癌的女性来说，保乳治疗(BCT)是一种公认的治疗选择。保乳手术后的全乳房照射(WBI)大大降低了乳房复发的风险。然而，长达5-7周的WBI疗程大大降低了妇女的生活质量，特别是对于居住在远离放射治疗(RT)设施的老年人和妇女来说，这是一个后勤问题。为了改善BCT的可及性和方便性，人们正在研究加速部分乳腺照射(APBI)。研究表明，BCT后75%的乳房复发发生在肿瘤床，这意味着在选定的女性中，RT可能仅限于肿瘤床。通过限制受照射的乳房体积，可以加速辐射剂量的传递并减少总体治疗时间。此外，较短的时间表允许更有效地使用RT资源。为了确定APBI是否可以取代WBI作为选择接受BCT治疗的早期乳腺癌患者的标准护理，有必要证明其技术可行性以及与WBI相比结果的等效性。本研究采用一种新技术研究了APBI治疗早期乳腺癌的可行性、毒性、美容效果、局部控制性和生活质量。它使用先进的三维RT计划和多个区域的形状，以符合目标体积(肿瘤床)，并保留正常器官。它比其他方式更有可能成为澳大利亚首选的APBI技术，因为它使用的是大多数RT中心随时可用的设备，而且是非侵入性的，可能会受到患者的青睐。然而，它在拥有不同RT设备的多个澳大利亚中心的可行性尚不清楚。鉴于目前国际上的高度关注，现在进行这项可行性研究是适时的，为大规模研究做准备，以确定APBI是否可以在BCT中取代WBI。

Breast conserving therapy (BCT) is an accepted treatment option for most women with early breast cancer. Whole breast irradiation (WBI) after breast conserving surgery substantially reduces the risk of breast recurrence. However, the prolonged 5-7 week course of WBI substantially decreases the quality of life (QoL) experienced by women and is a logistical problem particularly for the elderly and women who reside far from a radiotherapy (RT) facility. In order to improve the access and convenience of BCT, accelerated partial breast irradiation (APBI) is being investigated. Research shows that 75% of the breast recurrences occur at the tumour bed after BCT implying that in selected women, RT may be limited to the tumour bed only. By limiting the breast volume irradiated, it is feasible to accelerate radiation dose delivery and reduce overall treatment time. In addition, a shorter schedule permits more efficient use of RT resources. To determine if APBI could replace WBI as standard of care for selected women with early breast cancer treated with BCT, it is necessary to demonstrate its technical feasibility and equivalence of outcomes compared to WBI. This study investigates the feasibility, toxicity, cosmetic outcome, local control and QoL of women with early breast cancer treated with APBI using a novel technique. It uses advanced 3-dimensional RT planning and multiple fields shaped to conform to the target volume (tumour bed) and spare the normal organs. It is more likely than the other modalities to be adopted as the preferred APBI technique in Australia because it uses equipments readily available in most RT centres and being non-invasive, is likely to be preferred by patients. However, its feasibility in multiple Australian centres with varying RT equipments is unclear. Given the current high level of international interest, it is timely to conduct this feasibility study in preparation for large scale research to determine if APBI may replace WBI in BCT.