Shrinkage of head and neck cancer specimens after formalin fixation.

BACKGROUND We conducted this study to investigate whether formalin fixation is associated with the shrinkage of head and neck cancer specimens. METHODS Patients scheduled to undergo operation were eligible for enrollment. Fresh specimens were measured immediately in the operating room, and the measurements were repeated after formalin fixation. RESULTS A total of 100 specimens were collected. Nearly half of them were obtained from the oral cavity (n=49), and a large majority were squamous cell carcinoma (n=69). The average decreases in length, width, and depth after formalin fixation were 1.50mm (4.40%), 1.52 mm (6.18%), and 0.67 mm (4.10%), respectively. There was no significant difference in the shrinkage percentage associated with gender, age, tumor site, tumor size, or histology. CONCLUSION We found that head and neck cancer specimens shrink after formalin fixation. Therefore, we recommend that the specimen be measured immediately in order to avoid the underestimation of tumor size.