Association of tumor strain ratio with prognostic factors in invasive breast cancer

We evaluate the correlations between tumor strain ratio value and prognostic factors for breast cancers. Fifty-seven women with invasive breast cancer underwent ultrasound elastography prior to surgery. Elastography strain ratio (SR), defined as the fat-to-lesion ratio, was recorded for each lesion using the software in the ultrasound equipment. We evaluated the associations between tumor SR and pathological prognostic factors such as tumor subtype, tumor size, axillary lymph node metastasis, histological grade, vascular invasion, and hormonal receptor status. We found a significant correlation between tumor SR and progesterone receptor (PR) status (p = 0.02). Tumors with axillary lymph node metastasis had a higher SR value than those without lymph node metastasis; however, this difference was not significant. Strain elastography revealed that grade 3 tumors had softer tissues than grade 1 and 2 tumors, although this was not statistically significant. The tumor SR value was not significantly correlated with tumor subtypes, tumor size, vascular invasion, and estrogen receptor or cell surface human epidermal growth factor 2 status (p > 0.05). The present study demonstrated no significant correlation between SR values and prognostic factors, except for PR status. However, tumors with LN metastasis tended to exhibit greater stiffness, and higher grade tumors exhibited lower stiffness owing to necrosis. Further studies with large study population on tumor-associated stiffness are required.