Abstract P5-16-15: 3D symmetry of pre-operative breasts in cancer patients
Authors: Nicklaus KM , Cheong AL , Liu J , Reece GP , Bordes MC , Hanson SE , Markey MK , Merchant FA 
Published: May 2019

Abstract
INTRODUCTION
Achieving breast symmetry and mitigating ptosis are important aims of cosmetic and reconstructive breast surgery. Breast asymmetry typically occurs when the left and right breasts differ in size, shape, or position. A few studies have associated breast asymmetry to hormonal changes and breast cancer risk. Similarly, changes in breast ptosis have been attributed to age, BMI, breast volume, smoking history, pregnancy, and weight loss. The purpose of this study is to provide normative data and understand factors that may attribute to breast asymmetry and ptosis.
MATERIAL AND METHODS
The dataset consisted of 87 surface images of women scheduled to undergo mastectomy for the prevention or treatment of breast cancer. Patients were enrolled in an IRB approved research study from 2011 to 2014 at MD Anderson Cancer Center (Houston, TX). Images were obtained using 3dMDTorso (3dMD LLC, Atlanta, GA). Patient demographics were recorded and tumor size was obtained from MD Anderson Breast Cancer Management System, and tumor location data were obtained through a search of the MD Anderson Tumor Registry Database. Patients with a BMI &gt; 41, rare congenital breast abnormalities, radiation therapy, or major breast surgeries were excluded. Breast symmetry was assessed by computing the ratio of the sternal notch (SN) to nipple (N) distance and breast volume ratio of the left and right breasts. Perfect symmetry occurs when the ratio is one. The smaller breast was evaluated over the larger breast so that ratios were less than one. A plastic surgeon rated each breast for ptosis. The correlation between age, BMI, and symmetry parameters were assessed using Pearson's r, Spearman's rho, and Kendall's tau coefficients. A multivariable linear model was used to evaluate the association between the ratios and demographic factors. A multiple ordinal logistic regression analysis was performed for age, BMI, and breast volume against ptosis.
RESULTS
The average sternal notch to nipple (SN-N) distance was 24.1 ± 3.30 cm and the SN-N ratio was 0.975 ± 0.020. The average breast volume was 794 ± 323 cc and the breast volume ratio was 0.914 ± 0.065. When comparing the right and left breasts, for SN-N distances, we found that 58.6% of the patients had a difference of less than 5 mm, 17.3% of the patients had a difference between 5 and 10 mm, and 24.1% of the patients had a difference greater than 10 mm. For volume, 49.4% of the patients had less than 50 cc of difference, 21.5% of the patients had a difference between 50 and 100 cc, and 29.1% of the patients differed by more than 100 cc. Tumor size did not significantly affect breast volume based on the t-test (p = 0.181). Symmetry ratios did not show significant correlation with age or BMI. Age and BMI were also not significantly associated with ptosis (p&gt;0.05), but larger breast volumes were associated with increasing degree of ptosis (OR: 1.14; 95% CI: 1.06-1.22; p&lt;0.001).
CONCLUSION
Our findings indicate that larger breast volumes are associated with increased ptosis grade. Age and BMI did not appear to significantly impact asymmetry or ptosis.
Citation Format: Nicklaus KM, Cheong AL, Liu J, Reece GP, Bordes MC, Hanson SE, Markey MK, Merchant FA. 3D symmetry of pre-operative breasts in cancer patients [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 P5-16-15.