Background: The surgeon’s intraoperative assessment (IOA) of extent of resection has been proffered as a potentially useful means of predicting recurrence rates after surgery for benign tumors such as meningiomas, despite many studies showing data to the contrary. Studies of surgeon’s assessment compared with post-operative MRI after removal of pituitary adenomas has not been previously investigated.
Methods: A retrospective review of consecutive patients with pituitary adenomas operated on by a single surgeon was performed. IOA of tumor resection was recorded by the senior surgeon at the conclusion of the operation (THS). Preoperative and postoperative MRI scans were obtained for all patients and radiographic extent of resection was determined by neuroradiology. Radiographic recurrence and need for further intervention were examined and correlated with extent of resection.
Results: Three hundred seventeen consecutive patients undergoing resection of a non-hormone producing pituitary adenomas were included. While IOA GTR was reported in 90%, MRI revealed GTR in only 67%. The positive predictive value of IOA was 74% and the negative predictive value was 84%. After a mean follow-up of 41 months, there was a 15.8% recurrence rate. Patients with IOA GTR and STR recurred at rates of 13.3% and 36%, respectively. Patients with radiographic GTR and STR recurred at rates of 6.7% and 35.2% respectively. Discordant cases with IOA GTR and MRI STR (n=52) recurred at a rate of 31%. Discordant cases with IOA STR and MRI GTR (n=6) recurred at a rate of 0%.
Conclusion: Post-operative MRI was more sensitive at picking up residual tumor and predicting recurrence than the surgeon’s intraoperative assessment. This study provides further evidence that surgeon’s intraoperative assessment of extent of resection is a poor metric compared with post-operative imaging.