Evolution of postoperative pituitary adenoma resection cavities assessed by magnetic resonance imaging and implications regarding radiotherapy timing and modality.

Purpose: This study evaluates the temporal evolution of the spatial relationship between the pituitary adenoma transsphenoidal surgical cavity and the adjacent optic chiasm and discusses implications on timing and choice of radiotherapy modality.

Methods: This retrospective observational review analyzed factors that might influence the postoperative relationship between the surgical cavity and the optic chiasm, including tumor type, craniocaudal tumor and resection cavity dimensions, the preoperative distance between tumor and the optic chiasm, the presence of cavernous sinus invasion, and the choice of intraoperative packing material. Changes observed on magnetic resonance imaging in the preoperative, immediate (within 72 h), and delayed (≥3 months) postoperative periods were compared.