Skaane P
Department of Radiology, Ullevaal University Hospital, Oslo, Norway.
Acta Radiol Suppl. 1999;420:1-47.
The aims of the study was to analyze the features of cancers missed as tumor on ultrasonography (US), to determine the predictive power of US tumor descriptors in the differentiation of benign and malignant breast tumors, to evaluate US as adjunct to mammography, and to assess the validity and reliability of mammographic, US, and combined interpretation of breast tumors.
Prospectively recorded mammographic and US findings of 355 malignant breast tumors among 2,985 consecutive patients who underwent breast US were compared with clinical findings and pathologic subtypes of the tumors. In addition, a 10-year material of 95 invasive lobular carcinomas (ILCs) were investigated. Three retrospective studies assessed the validity and reliability of mammographic, US, and combined interpretation of 200 palpable mammographically noncalcified breast masses by four radiologists.
A total of 97.5% of the palpable and 67.9% of the nonpalpable malignant neoplasms were detected as tumor on US. Most carcinomas missed as tumor on US were ductal carcinomas in situ (DCISs) and microinvasive ductal cancers dominated by DCIS manifesting with suspicious calcifications on mammography. Irregular shape, irregular contour, extensively hypoechogenicity, hyperechoic rim (halo), and distortion of the surrounding tissue were the US features with the highest odds of predicting carcinomas. A pseudocapsule is the strongest predictor of a benign tumor, the odds of cancer being 0.03 in nonpalpable and 0.08 in palpable breast tumors. A negative predictive value of 100% in palpable and 96% in nonpalpable tumors was achieved using strict US criteria. In patients with ILC, US measurements predicted tumor size more accurately than mammography. US as adjunct to mammography correctly diagnosed ("upgraded") 9.5% of tumors with benign or indeterminate mammographic diagnoses. Excluding mammographically conclusive malignant tumors and carcinomas presenting with microcalcifications. US correctly upgraded 42% of the palpable and 44% of the nonpalpable cancers. Combined mammographic-US interpretation offers the highest diagnostic performance in noncalcified breast tumors. The lowest interobserver agreement was found in US interpretation.
The impact of US in mixed cancer populations is limited. US is, however, a valuable adjunct to mammography in patients with nonconclusive mammographic findings. Negative predictive values on US approaching 100% may be achieved using strict criteria for a benign diagnosis. A considerable interobserver variation in the US interpretation is a limiting factor for the potential of breast US in the differentiation of benign and malignant breast tumors.
本研究旨在分析超声检查（US）漏诊为肿瘤的癌症特征，确定US肿瘤描述符在鉴别乳腺良恶性肿瘤中的预测能力，评估US作为乳腺X线摄影辅助手段的价值，并评估乳腺X线摄影、US及两者联合解读乳腺肿瘤的有效性和可靠性。
前瞻性记录2985例接受乳腺US检查的连续患者中355例恶性乳腺肿瘤的乳腺X线摄影和US检查结果，并与肿瘤的临床发现和病理亚型进行比较。此外，还对95例浸润性小叶癌（ILC）的10年资料进行了研究。三项回顾性研究评估了四位放射科医生对200例乳腺X线摄影可触及的非钙化乳腺肿块进行乳腺X线摄影、US及两者联合解读的有效性和可靠性。
US检查中，97.5%的可触及恶性肿瘤和67.9%的不可触及恶性肿瘤被检测为肿瘤。US漏诊为肿瘤的大多数癌症为导管原位癌（DCIS），以DCIS为主的微浸润性导管癌在乳腺X线摄影上表现为可疑钙化。不规则形状、不规则轮廓、广泛低回声、高回声边缘（晕环）及周围组织变形是预测癌症可能性最高的US特征。假包膜是良性肿瘤的最强预测指标，在不可触及乳腺肿瘤中癌症可能性为0.03，在可触及乳腺肿瘤中为0.08。使用严格的US标准，可触及肿瘤的阴性预测值为100%，不可触及肿瘤为96%。在ILC患者中，US测量比乳腺X线摄影更准确地预测肿瘤大小。US作为乳腺X线摄影的辅助手段，正确诊断（“升级”）了9.5%乳腺X线摄影诊断为良性或不确定的肿瘤。排除乳腺X线摄影确诊的恶性肿瘤和伴有微钙化的癌症，US正确升级了42%的可触及癌症和44%的不可触及癌症。乳腺X线摄影-US联合解读在非钙化乳腺肿瘤中具有最高的诊断性能。在US解读中观察者间一致性最低。
US在混合癌症人群中的影响有限。然而，对于乳腺X线摄影结果不确定的患者，US是乳腺X线摄影的有价值辅助手段。使用严格的良性诊断标准，US的阴性预测值可接近100%。US解读中观察者间差异较大是乳腺US在鉴别乳腺良恶性肿瘤潜力方面的一个限制因素。
