Significance of Simpson grading system in modern meningioma surgery

J Neurosurg 117:121–128, 2012. http://thejns.org/doi/abs/10.3171/2012.3.JNS111945

Techniques for the surgical treatment of meningioma have undergone many improvements since Simpson established the neurosurgical dogma for meningioma surgery in his seminal paper published in 1957. This study aims to assess the clinical significance and limitations of the Simpson grading system in relation to modern surgery for WHO Grade I benign meningiomas and to explore the potential of the cell proliferation index to complement the limitations in predicting their recurrence.

Methods. The surgical records of patients who underwent resection of intracranial meningiomas at the University of Tokyo Hospital between January 1995 and August 2010 were retrospectively analyzed. The authors investigated the relationships between recurrence-free survival (RFS) and Simpson grade or MIB-1 labeling index value.

Results. A total of 240 patients harboring 248 benign meningiomas were included in this study. Simpson Grade IV resection was associated with a significantly shorter RFS than Simpson Grade I, II, or III resection (p < 0.001), while no statistically significant difference was noted in RFS between Simpson Grades I, II, and III. Among meningiomas treated by Simpson Grade II and III resections, however, multivariate analysis revealed that an MIB-1 index of 3% or higher was associated with a significantly shorter time to recurrence.

Conclusions. The clinical significance of the different management strategies related to Simpson Grade I–III resection may have been diluted in the modern surgical era. The MIB-1 index can differentiate tumors with a high risk of recurrence, which could be beneficial for planning tailored optimal follow-up strategies. The results of this study appear to provide a significant backing for the recent shift in meningioma surgery from attempting aggressive resection to valuing the quality of the patient’s life.

Residual nonfunctioning pituitary adenomas: prognostic value of MIB-1 labeling index for tumor progression

J Neurosurg 111 (3)563-571. DOI: 10.3171/2008.4.17517

In residual nonfunctioning pituitary adenomas, reliable prognostic parameters indicating probability of tumor progression are needed. The Ki 67 expression/MIB-1 labeling index (LI) is considered to be a promising candidate factor. The aim in the present study was to analyze the clinical usefulness of MIB-1 LI for prognosis of tumor progression.

Methods: The authors studied a cohort of 92 patients with nonfunctioning pituitary adenomas. Based on sequential postoperative MR images, patients were classified as tumor free (51 patients) or as harboring residual tumor (41 individuals). The residual tumor group was further subdivided in groups with stable residual tumors (14 patients) or progressive residual tumors (27 patients). The MIB-1 LI was assessed in tumor specimens obtained in all patients, and statistical comparisons of MIB-1 LI of the various subgroups were performed.

Results: The authors found no significant difference of MIB-1 LI in the residual tumor group compared with the tumor-free group. However, MIB-1 LI was significantly higher in the progressive residual tumor group, compared with the stable residual tumor group. Additionally, the time period to second surgery was significantly shorter in residual adenomas showing an MIB-1 LI > 3%.

Conclusions: The data indicate that MIB-1 LI in nonfunctioning pituitary adenomas is a clinically useful prognostic parameter indicating probability of progression of postoperative tumor remnants. The MIB-1 LI may be helpful in decisions of postoperative disease management (for example, frequency of radiographic intervals, planning for reoperation, radiotherapy, and/or radiosurgery).