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

保乳治疗（BCT）是大多数早期乳腺癌女性接受的治疗选择。保乳手术后的全乳照射（WBI）大大降低了乳腺复发的风险。然而，WBI的延长的5-7周疗程大大降低了女性经历的生活质量（QoL），并且是一个后勤问题，特别是对于老年人和居住在远离放射治疗（RT）设施的女性。为了提高BCT的可及性和便利性，加速部分乳腺照射（APBI）正在研究中。研究表明，75%的乳腺癌复发发生在BCT后的肿瘤床，这意味着在选定的女性中，RT可能仅限于肿瘤床。通过限制照射的乳房体积，可以加速辐射剂量输送并减少总体治疗时间。此外，更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BCT治疗的早期乳腺癌选定女性的标准治疗，有必要证明其技术可行性和与WBI相比的结果等效性。本研究探讨了使用新技术的APBI治疗早期乳腺癌女性的可行性、毒性、美容结局、局部控制和生活质量。它使用先进的三维RT计划和多个形状符合目标体积（肿瘤床）的字段，并保留正常器官。在澳大利亚，它比其他模式更有可能被采纳为首选的APBI技术，因为它使用了大多数RT中心现成的设备，并且是非侵入性的，可能是患者的首选。然而，其可行性在多个澳大利亚中心与不同的RT设备尚不清楚。鉴于目前国际上的高度兴趣，进行这项可行性研究是及时的，为大规模研究做准备，以确定APBI是否可以取代BCT中的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.