三塚 幸夫¹, 金澤 真作², 緒方 秀昭², 丸山 憲一¹, 八鍬 恒芳¹, 久保田 伊哉², 齊藤 芙美², 根本 哲生³, 澁谷 和俊³, 金子 弘真²

Yukio MITSUZUKA¹, Shinsaku KANAZAWA², Hideaki OGATA², Kenichi MARUYAMA¹, Tsuneyoshi YAKUWA¹, Yorichika KUBOTA², Fumi SAITO², Tetsuo NEMOTO³, Kazutoshi SHIBUYA³, Hironori KANEKO²

¹東邦大学医療センター大森病院臨床生理機能検査部, ²東邦大学医学部外科学講座一般・消化器外科分野, ³東邦大学医療センター大森病院病理部

¹Department of Clinical Functional Physiology, Toho University Omori Medical Center, ²Division of General and Gastroenterological Surgery, Department of Surgery, Toho University School of Medicine, ³Department of Pathology, Toho University Omori Medical Center

キーワード : breast ultrasound, contrast-enhanced ultrasound, Sonazoid<SUP>&reg;</SUP>, breast cancer, neoadjuvant chemotherapy

目的：一般に乳癌術前化学療法（neoadjuvant chemotherapy: NAC）の臨床的効果判定は病変の最大径の変化によってなされるが，内部の壊死や瘢痕組織の残存により正確にとらえられない症例もある．そこで我々は，Sonazoid^®造影超音波（以下，CEUS）を加えることでより正確な効果判定が可能であるか，またどのようなCEUS所見に注目するべきか検討した．対象と方法：対象は2007年7月‐2010年7月に当院でNAC後に手術を施行した乳癌患者のうち，NAC前後にCEUSを行った20症例22結節．Sonazoid^®懸濁液0.0075 ml/kgを静脈内投与．投与後1分間の動画とMicro Flow Imagingをもとに，腫瘤内部の染影を染影なし／非腫瘤部と同程度の染影／非腫瘤部よりやや強い染影／非腫瘤部より明らかに強い染影／評価不能の5段階に，腫瘤周囲の染影および腫瘤内部の不染域を無／有／評価不能の3段階に分類し，NACの組織学的効果判定と比較検討した．結果と考察：NAC前にみられた腫瘤内部および周囲の染影がNAC後に低下する傾向がみられ，組織学的効果判定の高い群でその傾向はより強くみられた．腫瘤内部の不染域に関しては組織学的効果判定と一定の傾向はみられず，単に不染域の有無だけでなく，腫瘤サイズの変化や染影部分の状態なども加味しながら評価する必要があると考えられた．結論：CEUSにより腫瘤内部と周囲の染影を評価することで，NACの効果を評価できる可能性が示唆された．

Purpose: The change in maximum tumor diameter is generally used to evaluate clinical response to neoadjuvant chemotherapy (NAC) for breast cancer. However, there are cases in which accurate evaluation cannot be performed due to internal necrosis or scar tissue. The objectives of this study were to examine whether accurate evaluation can be performed by addition of contrast-enhanced ultrasound (CEUS) using Sonazoid^® and to examine on what types of CEUS findings one should focus. Subjects and Methods: The subjects were 20 breast cancer patients (22 nodules) who had undergone CEUS before and after NAC followed by surgery in our hospital between July 2007 and July 2010. Sonazoid^® suspension (0.0075 ml/kg) was injected intravenously. The nodules were classified into the following five categories based on micro flow images and video taken for 1 min after injection: the tumor interior was not contrast enhanced, had the same enhancement as the non-tumor area, was slightly more enhanced than the non-tumor area, was more strongly enhanced than the non-tumor area, and was non-evaluable. Three categories were used to classify peritumoral contrast enhancement and intratumoral non-contrast enhanced areas: absent, present, and non-evaluable. The results based on these categories were compared with histological responses to NAC. Results and Discussion: Peritumoral and intratumoral contrast enhancement tended to decrease after NAC compared with before NAC. This tendency was stronger in nodules that showed a good histological response. There was no consistent trend between histological responses and intratumoral non-enhanced areas. It suggests the need to evaluate not only absence or presence of non-enhanced areas but also changes in tumor size and the state of enhanced areas. Conclusion: The effectiveness of NAC can be evaluated by the assessment of intratumoral and peritumoral contrast enhancement using CEUS.