Limitations of stereotactic biopsy in the initial management of gliomas

Stereotactic biopsy is often performed for diagnostic purposes before treat ing patients whose imaging studies highly suggest glioma, Indications cited for biopsy include diagnosis and/or the "inoperability" of the tumor. This study questions the routine use of stereotactic biopsy in the initial mana gement of gliomas, At The University of Texas M, D, Anderson Cancer Center, we retrospectively reviewed a consecutive series of 81 patients whose imag ing studies suggested glioma and who underwent stereotactic biopsy followed by craniotomy/resection (within 60 days) between 1993 and 1998. All releva nt clinical and imaging information was reviewed, including computerized vo lumetric analysis of the tumors based on pre- and postoperative MRI. Stereo tactic biopsy was performed at institutions other than M, D, Anderson in 78 (96%) of 81 patients. The majority of tumors were located either in eloque nt brain (36 of 81 = 44%) or near-eloquent brain (41 of 81 = 51%), and this frequently was the rationale cited for performing stereotactic biopsy. Gro ss total resection (> 95%) was achieved in 46 (57%) of 81 patients, with a median extent of resection of 96% for this series. Diagnoses based on biops y or resection in the same patient differed in 40 (49%) of 82 cases. This d iscrepancy was reduced to 30 (38%) of 80 cases when the biopsy slides were reviewed preoperatively by each of three neuropathologists at M, D, Anderso n, Major neurologic complications occurred in 10 (12.3%) of 81 surgical pat ients and 3 (3.7%) of 81 patients undergoing biopsy. Surgical morbidity was probably higher in our series than it would be for glioma patients in gene ral because our patients represent a highly selected subset of glioma patie nts whose tumors present a technical challenge to remove. Stereotactic biop sy is frequently inaccurate in providing a correct diagnosis and is associa ted with additional risk and cost. If streotactic biopsy is performed, expe rt neuropathology consultation should be sought.