Abstract P1-02-11: The difference between tumor width on a contrast-enhanced ultrasound and the extent of pathological breast cancer
Authors: Noro Aya , Shima Hiroaki , Hirai Toshiko , Noma Midori , Nakamura Takashi , Sato Emi , Kaga Terumi , Mitsuzuka Yukio , Kamei Keitaro , Imayoshi Yumi , Ito Toshikazu , Kanazawa Shinsaku , Kato Kumiko , Sekiguchi Ryuzo , Kutomi Goro , Mori Mitsuru , Hasegawa Tadashi , Takemasa Ichiro , Okuno Toshitaka 
Published: March 2020

Background: Contrast-enhanced ultrasound (CEUS) is a modality capable of visualizing the blood vessels through the use of the microbubble agent “Perflubutane”. It can also allow for an improved visualization of breast tumors. Currently, CEUS is being used on a daily practice for breast cancer screening and treatment planning in many medical centers. This technique was approved in Japan following evidence gleaned through Phase-2 and Phase-3 clinical studies and has advanced over the past seven years. Regarding the extent of malignant breast tumor, it has been revealed that contrast-enhanced lesions observed using CEUS might be longer than those same lesions visible on B-mode. However, what contrast-enhanced images on CEUS reflect pathologically remains unclear. To resolve this issue, more complete evidence of the detailed imagery of lesions obtained by CEUS seemed to be needed. In the present study, we investigated the maximum tumor width on B-mode/CEUS images compared with the maximum pathological extent of the cancer. (Evergreen study, UMIN: 000028995).

Methods: In this retrospective multi-center study, 153 operable breast cancer patients who had undergone B-mode and CEUS prior to breast surgery between August 2012 and January 2017 were registered. The maximum tumor width was measured on B-mode and CEUS, and the tumor diameter width was determined at a postoperative histopathological examination (P) by investigators. With five blind readers as independent reviewers, the lesion width of 303 images was read (B-mode and CEUS). We analyzed the difference between the lesion width on CEUS or B-mode and the pathological width using paired t-tests and the Pearson product-moment correlation coefficient.

Results: The mean tumor widths (±standard deviation) measured by investigators were 15±7 mm (B-mode), 19±8 mm (CEUS) and 17±9 mm (P). The difference calculated by P from B-mode was -3±7 mm (p&lt;0.0001, r=0.6142), while that from CEUS was 1±6 mm (p=0.0163, r=0.7372). CEUS showed a significantly positive high correlation (p&lt;0.0001, r=0.8548) with B-mode. The mean (±standard deviation) widths measured by blind readers were 16±7 mm (B-mode) and 18±8 mm (CEUS). The difference calculated by

P from B-mode was -2±8 mm (p=0.0005, r=0.5067), while that from CEUS was 1±8 mm (p=0.1256 r=0.5354). CEUS and B-mode also showed a significantly positive high correlation (p&lt;0.0001, r=0.7909).

Discussion: Our data suggested that the maximum lesion width might increase, in order, from B-mode to P and CEUS. Furthermore, the difference in the lesion width determined by B-mode and P appeared to be significant, although not that between P and CEUS. Moreover, a positive high correlation was detected between B-mode and CEUS. Therefore, the width on CEUS might tend to be larger than that on B-mode, regardless of the tumor size. Additional information may be determined through an analysis of the design and extent of dissection when partial mastectomy is to be performed. These findings may also provide clues as to what can be anticipated pathologically when a lesion is enhanced with CEUS.

Citation Format: Aya Noro, Hiroaki Shima, Toshiko Hirai, Midori Noma, Takashi Nakamura, Emi Sato, Terumi Kaga, Yukio Mitsuzuka, Keitaro Kamei, Yumi Imayoshi, Toshikazu Ito, Shinsaku Kanazawa, Kumiko Kato, Ryuzo Sekiguchi, Goro Kutomi, Mitsuru Mori, Tadashi Hasegawa, Ichiro Takemasa, Toshitaka Okuno. The difference between tumor width on a contrast-enhanced ultrasound and the extent of pathological breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-02-11.