Reducing mastectomy rates in invasive lobular carcinoma by high-resolution 3D breast CT

 描述(申请人提供)：乳腺癌是仅次于浸润性导管癌(IDC)的第二种最常见的乳腺癌，占所有乳腺癌的10%-15%。与其他乳腺癌相比，小叶癌表现为多灶性、多中心性和双侧性疾病。在组织学类型中，浸润性小叶癌的再切除率最高(28.3%)，显著高于浸润性导管癌(19.1%)。对于被诊断为小叶癌的受试者，目前乳腺MRI是评估疾病程度的首选方法，因为超声和乳房X光检查在准确估计肿瘤大小方面表现较差。汇总数据的Meta分析显示，乳腺MRI对检测小叶癌的敏感度为93.3%，在同侧和对侧乳房分别有32%和7%的患者发现额外的病变。然而，对于大约25%到35%的肿瘤，从乳腺MRI估计的大小与病理结果相差超过1厘米。术前使用乳房MRI评估病变程度与乳房切除的几率增加有关。最近的一项研究分析了243例浸润性小叶癌(ILC)，认为保守手术治疗ILC是安全的，但需要对肿瘤大小和多灶性进行更准确的术前评估，以降低再次切除率。我们假设，由专用乳腺CT提供的高空间分辨率3D成像能够分辨200至250微米范围的特征，将提高与组织病理学大小一致的肿瘤的比例，因此将增加受试者接受保乳手术的可能性。专用乳房CT不需要对乳房进行物理压缩，扫描一次需要10秒。这项前瞻性临床研究旨在探讨增强乳腺MRI观察到的所有病灶是否也能在增强乳腺CT(敏感性)上看到，以及乳腺CT确定的肿瘤大小是否比乳腺MRI更符合病理。本研究还将研究两种自动分割和肿瘤大小量化的方法，以手术病理肿瘤大小为参考标准，确定哪种定量算法更准确。因此，这项拟议的研究对现有的关于肿瘤大小测量准确性的范例提出了挑战，并为降低乳腺癌切除率铺平了道路。

 DESCRIPTION (provided by applicant): Cancers of the breast are the second most common type of breast cancers (after invasive ductal carcinoma, IDC) and account for 10-15% of all breast cancers. More than any other breast cancer, lobular cancers present as multifocal, multicentric and bilateral disease. Among histological types, re- excision rates are highest (28.3%) for invasive lobular carcinoma and substantially more than invasive ductal carcinoma (19.1%). For subjects diagnosed with lobular carcinoma, breast MRI is currently the preferred modality for evaluating disease extent as ultrasound and mammography have been shown to be inferior in accurately estimating tumor size. Meta-analysis of pooled data have shown that breast MRI has a sensitivity of 93.3% for detecting lobular carcinoma with additional lesions detected in 32% and 7% of patients in the ipsilateral and contralateral breasts, respectively. However, for approximately 25% to 35% of tumors, the size estimated from breast MRI differs from pathology by more than 1 cm. The use of pre-operative breast MRI for evaluating disease extent has been associated with increased odds for mastectomy. A recent study analyzing 243 patients with invasive lobular carcinoma (ILC) concluded that ILC can be safely treated with conservative surgery but a more accurate preoperative evaluation of tumor size and multifocality is needed to reduce re-excision rate. We hypothesize the high spatial resolution 3D imaging provided by dedicated breast CT that is capable of resolving features in the 200 to 250 microns range would improve the proportion of tumors that are concordant in size with histopathology and hence would increase the likelihood of subjects being treated with breast conserving surgery. Dedicated breast CT does not require physical compression of the breast and takes 10 seconds for a scan. This prospective clinical study is designed to address if all foci observed with contrast-enhanced breast MRI are also visible with contrast-enhanced breast CT (sensitivity) and if the tumor size determined from breast CT is more concordant with pathology than breast MRI. The study will also investigate two automated segmentation and tumor size quantification methods to determine, which quantitative algorithm is more accurate, with tumor size from surgical pathology serving as reference standard. Thus, the proposed study challenges existing paradigms on the accuracy of tumor size measurements and paves for the way for reducing mastectomy rates.