Department of Radiation and Cellular Oncology, University of Chicago Medical Center, Chicago, Illinois, USA.
Int J Radiat Oncol Biol Phys. 2013 Mar 1;85(3):615-22. doi: 10.1016/j.ijrobp.2012.06.014. Epub 2012 Jul 24.
Retrospective data have demonstrated that breast magnetic resonance imaging (MRI) may change a patient's eligibility for partial breast irradiation (PBI) by identifying multicentric, multifocal, or contralateral disease. The objective of the current study was to prospectively determine the frequency with which MRI identifies occult disease and to establish clinical factors associated with a higher likelihood of MRI prompting changes in PBI eligibility.
At The University of Chicago, women with breast cancer uniformly undergo MRI in addition to mammography and ultrasonography. From June 2009 through May 2011, all patients were screened prospectively in a multidisciplinary conference for PBI eligibility based on standard imaging, and the impact of MRI on PBI eligibility according to National Surgical Adjuvant Breast and Bowel Project protocol B-39/Radiation Therapy Oncology Group protocol 0413 entry criteria was recorded. Univariable analysis was performed using clinical characteristics in both the prospective cohort and in a separate cohort of retrospectively identified patients. Pooled analysis was used to derive a scoring index predictive of the risk that MRI would identify additional disease.
A total of 521 patients were screened for PBI eligibility, and 124 (23.8%) patients were deemed eligible for PBI based on standard imaging. MRI findings changed PBI eligibility in 12.9% of patients. In the pooled univariable analysis, tumor size ≥ 2 cm on mammography or ultrasonography (P=.02), age <50 years (P=.01), invasive lobular histology (P=.01), and HER-2/neu amplification (P=.01) were associated with a higher likelihood of MRI changing PBI eligibility. A predictive score was generated by summing the number of significant risk factors. Patients with a score of 0, 1, 2, and 3 had changes to eligibility based on MRI findings in 2.8%, 13.2%, 38.1%, and 100%, respectively (P<.0001).
MRI identified additional disease in a significant number of patients eligible for PBI, based on standard imaging. Clinical characteristics may be useful in directing implementation of MRI in the staging of PBI candidates.
回顾性数据表明，乳腺磁共振成像（MRI）可以通过识别多中心、多灶性或对侧疾病，改变患者接受部分乳腺照射（PBI）的资格。本研究的目的是前瞻性地确定 MRI 发现隐匿性疾病的频率，并确定与 MRI 更有可能改变 PBI 资格相关的临床因素。
在芝加哥大学，所有乳腺癌患者除了接受乳腺 X 线摄影和超声检查外，还统一进行 MRI。从 2009 年 6 月至 2011 年 5 月，所有患者均在多学科会议上进行前瞻性筛查，根据标准影像学检查确定 PBI 资格，并根据国家外科辅助乳腺和肠道项目协议 B-39/放射治疗肿瘤学组协议 0413 入组标准记录 MRI 对 PBI 资格的影响。使用前瞻性队列和回顾性确定的患者的单独队列中的临床特征进行单变量分析。采用汇总分析得出预测 MRI 发现额外疾病风险的评分指数。
共有 521 例患者接受了 PBI 资格筛查，124 例（23.8%）患者根据标准影像学检查被认为有资格接受 PBI。MRI 检查结果改变了 12.9%患者的 PBI 资格。在汇总的单变量分析中，乳腺 X 线摄影或超声检查上肿瘤大小≥2cm（P=.02）、年龄<50 岁（P=.01）、浸润性小叶癌组织学（P=.01）和 HER-2/neu 扩增（P=.01）与 MRI 改变 PBI 资格的可能性更高相关。通过将显著危险因素的数量相加生成预测评分。评分分别为 0、1、2 和 3 的患者，MRI 检查结果改变 PBI 资格的比例分别为 2.8%、13.2%、38.1%和 100%（P<.0001）。
根据标准影像学检查，MRI 在许多有资格接受 PBI 的患者中发现了额外的疾病。临床特征可能有助于指导在 PBI 候选者的分期中实施 MRI。
