The pancake phenomenon contributes to the inaccuracy of margin assessment in patients with breast cancer

Background: To determine the effect on margin evaluation for patients with breast cancer, we prospectively quantified the “flattening” of the breast specimen after surgical removal. Methods: The volume and height of 100 consecutive breast biopsy specimens were recorded independently by the operating surgeon and the pathologist. Five factors were analyzed that were thought to contribute to changes in specimen dimensions: patient age, breast tissue density, mammographic lesion type, specimen size, and the use of compression during specimen radiography. Results: After surgical removal, mean volume and height of the breast specimens decreased from 46 cm3 to 29 cm3 (30%) and from 2.6 cm to 1.4 cm (46%), respectively. Flattening of the breast specimens occurred in all subgroups studied. Conclusions: Breast specimens are flattened after surgical removal, losing almost 50% of their original height. This “pancake” phenomenon has important implications for the accuracy of margin analysis.