Can strain elastography be used in reclassification of indeterminate breast lesions in BIRADS lexicon?: A prospective study

Breast cancer is the most commonly diagnosed cancer among women globally with approximately 2 million new cases in 2018. It is also the leading cause of cancer death among women worldwide with an estimated 626,679 deaths in 2018. Breast cancer is the most common cancer among Indian females with age adjusted rate as high as 25.8 per 100,000 women with high mortality about 12.7 per 100,000 women. Early detection is the key for successful management of breast cancer.

Various screening programs incorporating mammography and ultrasonography are being run worldwide, for the early detection of breast cancer. Using the standard American College of Radiology (ACR) Breast Imaging and Reporting Data System (BIRADS) lexicon, the lesions are placed in different categories, based on which clinical actions are taken. Most of the indeterminate lesions categorized into BIRADS 3 or 4A categories pose a diagnostic dilemma for the treating clinician and the reporting radiologist. They are low suspicion lesion with a reported incidence of malignancy as <10%. About 98% of the lesions, graded as BI-RADS 3, are histologically benign; the current guidelines suggest short-term follow-up. Nevertheless, about 2% of these lesions eventually turn out to be malignant, which are missed at the initial diagnosis.

Compliance with regular follow-up for BIRADS 3 lesions is poor, thereby prompting clinicians for biopsy over regular follow ups, which in most of the cases turn out to be negative. BI-RADS 4 lesions have a low-to-moderate probability of malignancy (2–94%), and biopsy is recommended. Among BI-RADS category 4A lesions, approximately only 2–9% turn out to be histologically malignant, and a much larger proportion of patients undergo invasive diagnostic procedures that could be avoided if a better noninvasive imaging technique was available for accurate diagnosis.

Conventional ultrasound is the most widely used and universally accessible modality for the evaluation of breast lesions. The relatively lower specificity of breast ultrasound has led to new developments in sonographic technology, and elastography is the most important technique to improve lesion characterization in breast ultrasonography based on lesion stiffness.

A prospective study was designed in our institute to determine whether strain elastography (SE) could downgrade or upgrade BI-RADS 3 and 4 lesions, thereby recoursing biopsies only to suspicious stiff lesions.