Abstract P2-08-43: Can optoacoustic imaging combined with ultrasound non-invasively offer prognosis for breast cancer molecular subtypes?
Authors: Menezes GL , Mann RM , Meeuwis C , Bisschops B , Veltman J , Lavin PT , van de Vijver MJ , Pijnappel RM 
Published: May 2019

Abstract
Aim: To investigate the role of optoacoustic imaging combined with gray-scale ultrasound (OA/US) to better differentiate between breast cancer molecular subtypes.
Materials and Methods:
This prospective 5-center study was performed in the Netherlands between March 2015 and February 2016. Only masses considered suspicious at conventional diagnostic breast ultrasound (US) were included. The study was approved by the institutional ethical boards of the participating hospitals and written informed consent was obtained from all patients. Dedicated breast radiologists evaluated the included masses using OA/US and scored the internal and external OA/US features accordingly. Spearman Correlation was used to analyze the relationship between OA/US features and mitotic figures. The same statistical method was also used to evaluate the correlation between OA/US features and percentages of ER, PR and Ki67. Wilcoxon-Mann-Whitney tests were used to analyze the relationship between OA/US features and molecular subtypes of breast cancer (Luminal A, Luminal B, Triple Negative and HER2-enriched breast cancers).
Results: Overall, 209 patients with 215 breast lesions were included in this study. Sixty-seven masses were considered malignant and the 59 masses classified as invasive breast cancers were included in the final mitotic figures, ER, PR, Ki-67 and molecular subtype analyses. Significant correlations were found between OA/US Total Internal Features and ER (p = 0.0333) and Ki-67 (p = 0.0092) percentages. Regarding molecular subtypes, Internal Vessels (p = 0.0257), Total Internal Features (p = 0.0196) and combined Total Internal and External Features (p = 0.0289) helped to differentiate between Luminal A and Luminal B cancers. Internal Vessels (p = 0.0030), Internal Blush (p = 0.0044), Total Internal Hemoglobin (p = 0.0053), Total Internal Features (p = 0.0010), Total Internal divided by Total External Features (p=0.0255) and combined Total Internal and External Features (p = 0.0108) helped to differentiate between Luminal A and Triple Negative breast cancers. Total Internal Features showed a borderline result (p = 0.0551) regarding the differentiation between Triple Negative and HER2-enriched subtypes.
Conclusions: The use of OA/US features to non-invasively differentiate between breast cancer molecular subtypes may help to establish an earlier prognosis and treatment planning, potentially decreasing costs and facilitating larger scale diagnosis. Future research with larger sample sizes may confirm these preliminary results.
Citation Format: Menezes GL, Mann RM, Meeuwis C, Bisschops B, Veltman J, Lavin PT, van de Vijver MJ, Pijnappel RM. Can optoacoustic imaging combined with ultrasound non-invasively offer prognosis for breast cancer molecular subtypes? [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-43.