Recurrence after gross-total resection of low-grade pediatric brain tumors: the frequency and timing of postoperative imaging

Abstract

OBJECT: Low-grade glial and glioneuronal brain tumors are frequently encountered in the pediatric population and can be effectively treated by resection. The authors aimed to use imaging to evaluate how often tumors recurred and to determine if recurrences were associated with any clinical symptoms, along with the financial costs of imaging, in patients with radiographically proven gross-total resection (GTR) at Boston Children's Hospital. These data were assessed to propose guidelines regarding postoperative surveillance. METHODS: The authors performed a retrospective cohort analysis of the Pediatric Brain Tumor Program database from 1993 to 2003 to identify patients with glial or glioneuronal tumors initially evaluated at Boston Children's Hospital. Among the 888 patients evaluated for any type of brain tumor during this period, 67 patients had WHO Grade I glial or glioneuronal lesions with radiographically proven GTR and available follow-up data. The frequency and timing of postoperative imaging was compared with the institutional protocol. Recurrence-free survival was calculated using the Kaplan-Meier method. Financial costs of imaging were available from 2001 to 2009 and were averaged to extrapolate the postoperative surveillance costs. RESULTS: Among the 67 patients with GTR, 13 recurrences were detected radiographically with a mean time to recurrence of 32.4 months (range 2.9-128.5 months). The mean duration of follow-up after surgery was 6.6 years. The recurrence-free survival at 2 and 5 years after GTR for all low-grade glial and glioneuronal tumors was 0.90 (95% CI 0.82-0.97) and 0.82 (95% CI 0.73-0.92), respectively. No clinical symptoms were associated with any of the recurrences, and no deaths occurred. Under the institutional protocol of surveillance imaging, the estimated cost per recurrence at 5 years was $104,094 per patient. The proposed protocol would reduce the number of MR scans in the first 5 years from 10 to 5, providing a potential cost savings of $52,047 per recurrence. CONCLUSIONS: Given the slow-growing, clinically asymptomatic nature of low-grade glial and glioneuronal tumors coupled with the financial and psychological costs of repeated imaging, the authors propose a postoperative surveillance MRI schedule that is less intensive than current institutional practice.