Optical palpation for tumor margin assessment in breast-conserving surgery

Area of Science:

• Biomedical Optics
• Surgical Oncology
• Medical Imaging

Background:

• Accurate intraoperative margin assessment is crucial for breast-conserving surgery to minimize re-excision rates.
• Optical palpation, a tactile imaging technique, measures tissue stiffness by mapping surface stress.
• Optical coherence tomography (OCT) is used to visualize tissue deformation during optical palpation.

Purpose of the Study:

• To evaluate the diagnostic accuracy of optical palpation for identifying tumor within 1 mm of excised breast specimen margins.
• To develop and test an automated classifier for optical palpation margin assessment.

Main Methods:

• Generated optical palpograms from 154 regions of interest in 71 excised breast tumor specimens.
• Developed an automated classifier using circle diameter and high-stress regions to predict margin status.
• Tested various parameters including circle diameters, stress thresholds, and tissue density filtering.

Main Results:

• The automated optical palpation classifier achieved 83.3% sensitivity and 86.2% specificity.
• These results surpass the 69.0% sensitivity and 79.0% specificity of OCT alone by human readers on the same dataset.
• Optical palpograms indicated that positive margins generally exhibit higher stress than negative margins across various cancer types.

Conclusions:

• Optical palpation, combined with an automated classifier, demonstrates significant potential for accurate intraoperative margin assessment in breast surgery.
• This technique offers improved diagnostic accuracy compared to OCT alone for identifying close tumor margins.
• Further development could lead to reduced re-excision rates and improved patient outcomes in breast-conserving surgery.