Breast, Chest Wall, and Thoracic Surgery Practice Test 2026 - Free Surgery Practice Questions and Study Guide

Negative margins mean the pathologist finds no cancer cells at the edge of the removed tissue when the specimen is inked and examined under the microscope. In practice, this is described as the margin being free of tumor cells, indicating the tumor has been completely excised with normal tissue around it. This is why it’s the best choice: a negative margin signifies no cancer at the cut edge, which is the goal of surgical excision. If tumor cells touch the inked edge, the margin is positive; if the status isn’t assessed or is unknown, that would not meet the definition of a negative margin. In clinical practice, achieving negative margins, especially in breast-conserving surgery, is linked to better local control, though the exact implications can depend on tumor type and other treatments.