Axillary LNs Evalution in Breast Cancer by Multimodal Us

Breast cancer (BrCa) is the most common malignant tumor affecting women globally, with its incidence and cancer-related mortality rates continuing to rise. Accurate evaluation of the presence, extent, and status of ALNs is critical for prognosis, disease staging, and treatment planning in patients with breast cancer.

Historically, axillary lymph node dissection (ALND), followed by histopathological evaluation, was the standard method for staging breast cancer. However, ALND is associated with short- and long-term complications such as lymphedema, nerve injury, seroma formation, and infection. To reduce these risks, sentinel lymph node biopsy (SLNB) has largely replaced ALND. While SLNB is less invasive and has fewer complications, it is still associated with a risk of false-negative results. According to the American Society of Oncology Guidelines, if SLNB results are negative, no further ALND is performed, as it does not confer a survival benefit. Patients with positive SLNB results, however, undergo a "completion" ALND.

Role of Ultrasound and Color Doppler Ultrasound:

Gray-scale ultrasound (US) is a non-invasive imaging modality widely used for the preoperative evaluation of ALNs in breast cancer patients. It provides valuable morphological information and facilitates obtaining tissue samples. However, its diagnostic accuracy is operator-dependent and limited to structural features of the lymph nodes. Adding Color Doppler Ultrasound (CDU) enhances this evaluation by providing functional insights, such as assessing vascular patterns and calculating the resistive index (RI) of ALNs. Despite their potential, US and CDU exhibit highly variable sensitivity and specificity across studies, which limits their standalone diagnostic utility.

Role of Ultrasound Elastography (UE):

Real-time strain ultrasound elastography (UE) is an advanced imaging technique that measures tissue stiffness, a property often associated with malignancy. Unlike US and CDU, UE can quantify stiffness, providing additional diagnostic insights. Elastography utilizes rhythmic manual compression to produce color-coded elastograms, which display differences in tissue stiffness. These elastograms are generated alongside conventional gray-scale US to ensure precise imaging of the same lymph node. Although UE has been explored for ALN assessment, existing studies report inconsistent results.

Recent meta-analyses suggest that UE offers valuable supplementary information for preoperative ALN evaluation and may influence surgical decision-making.

Other Imaging Modalities:

Alternative imaging techniques, including mammography, magnetic resonance imaging (MRI), multi-detector computed tomography (CT), and positron-emission tomography (PET-CT), have also been employed for ALN assessment. However, their widespread application is limited by moderate sensitivity, low specificity, high costs, radiation exposure, and the need for specialized imaging protocols for ALNs.

Multimodal Imaging:

Multimodal imaging, which combines two or more imaging techniques, provides a more comprehensive diagnostic approach than individual modalities alone. This study investigates the combined use of gray-scale US, CDU, and UE to improve diagnostic accuracy for ALN assessment in breast cancer patients.

This version addresses the study's purpose, methodology, and the role of each modality in greater detail