Is breast specimen shrinkage really a problem in breast-conserving surgery?

Breast-conserving surgery currently focuses on improving margin clearance and excision volume, the main pathology report parameters for oncological and cosmetic outcomes.

To quantitatively evaluate discrepancies in surgical and pathological estimates of breast specimen sizes, including the influence of formalin fixation.

This prospective multicentre study included 68 breast specimens of consecutive patients undergoing breast-conserving surgery for breast cancer in three affiliated hospitals between November 2010 to May 2011. Specimens were weighed immediately after excision. Specimen volumes were calculated from the length, width and height. Actual specimen volumes were measured using volume displacement. Specimens were weighed once again after arrival at the pathology department, and volumes recalculated. The smallest pre- and post-fixation distances to the tumour-free margin were compared.

The mean surgical specimen weight was 47.7 g and was approximately similar to the actual specimen volume of 49.8 cm(3). The weights of specimens immediately following surgery and on pathological appraisal were equal (p=0.94). The calculated volumes differed significantly from the actual specimen volumes (p>0.05). The mean distance to the closest tumour-free margin, 0.35 cm, was not altered by formalin fixation (p=0.1).

No evidence was found to suggest that surgical breast specimens shrink in the period between the surgical procedure and pathological examination, or following formalin fixation. The pathological appraisal of specimen margins and volumes is not affected by changes in specimen size. As calculations of specimen volumes are unreliable, the use of water displacement or the more readily available specimen weight is recommended for accurate volume measurement. Pathologists should be encouraged to always measure and record specimen weight.