Repeated operations for infiltrative low-grade gliomas without intervening therapy

Object. Progression of infiltrative low-grade gliomas (LGGs) has been reported previously. The limitations of such studies include diverse histological grading systems, intervening therapy, and the lack of histological confirmation of malignant tumor progression. The aim of this study was to determine tumor progression in adult patients with an initial diagnosis of infiltrative LGG who subsequently underwent a repeated operation, but no other intervening therapy. The authors examined factors that may be associated with tumor progression. Methods. The authors retrospectively reviewed a database of 300 patients with the initial diagnosis of LGG and who had been treated at their institution between 1990 and 2000. One hundred four of these patients had undergone a second surgery. Patients with infiltrative LGGs who had undergone two surgical procedures at least 3 months apart without intervening therapy were selected; the authors identified 40 patients who fit these criteria. Clinical, neuroimaging, and pathological data were centrally reviewed. There were 29 men and 11 women in the study, whose median age was 35.5 years (range 23-48 years). At the time of the second surgery, 50% of patients had experienced tumor progression. Patients whose tumors had progressed had a longer median time to repeated operation (49 compared with 22.5 months). Patients who had undergone gross-total resection, as demonstrated on postoperative magnetic resonance images, had a median time to repeated operation of 49 compared with 25 and 24 months in patients who underwent subtotal resection and biopsy, respectively (p = 0.02). The extent of resection did not influence the likelihood of tumor progression (p > 0.3). Conclusions. Fifty percent of patients with initially diagnosed infiltrative LGGs had tumor progression at the time of a repeated operation. A gross-total resection was associated with an increased time to repeated surgery. There was no statistically significant effect of gross-total resection as a predictor of tumor progression.