The effect of extent of resection on recurrence in patients with low grade cerebral hemisphere gliomas.

BACKGROUND: To evaluate the role of radical resection for low grade cerebral hemisphere gliomas, the authors analyzed the preoperative and postoperative radiographic tumor volumes (computed tomography hypodensity, magnetic resonance imaging-T2 signal hyperintensity) in 53 patients.
METHODS: Using a previously described method of computerized image analysis, the authors evaluated whether the percent of resection and volume of residual disease, postoperatively, influenced the incidence of recurrence, time to tumor progression, and histology of the recurrent tumor. Survival was not analyzed in this study.
RESULTS: No recurrence was detected, regardless of percent of resection and volume of residual disease, in patients with preoperative tumor volumes less than 10 cm2 (mean follow-up, 41.7 months). Patients with tumors measuring 10-30 cm3 had an incidence of recurrence and time to tumor progression of 13.6% and 58 months, respectively, compared with tumors measuring greater than 30 cm3, which had an incidence of recurrence and time to tumor progression of 41.2% and 30 months, respectively (P = 0.016). All patients (n = 13) who underwent a 100% resection had a recurrence-free follow-up period (mean, 54 months). In the remaining patients (n = 40), as the percent of resection decreased, the incidence of recurrence increased along with a shorter time to tumor progression (P = 0.03). Patients with a volume of residual disease of greater than 10 cm3 had a higher incidence of recurrence (46.2%) and a shorter time to tumor progression (30 months) compared with patients with a tumor volume of residual disease of less than 10 cm3 (incidence of recurrence, 14.8% and time to tumor progression, 50 months) (P = 0.002). Forty-six percent of patients with a tumor volume of residual disease of more than 10 cm3 had a recurrence of higher histologic grade, and this was significantly more frequent than patients with a volume of residual disease less than 10 cm3 (3.7%) (P = 0.0009). Age, radiotherapy, and histologic subtype had no influence on recurrence patterns.
CONCLUSION: For tumors greater than 10 cm3, the authors' data suggest that a greater percent of resection and a smaller volume of residual disease conveys a significant advantage, that is, terms of incidence of recurrence and the recurrent tumor phenotype, for patients with low grade cerebral hemisphere gliomas, compared with those who have a less aggressive resection or biopsy. While this may also be the case with tumors less than 10 cm3, further follow-up is necessary to determine the effect of surgery on recurrence patterns for this subset of patients.