Williams NL, et al. - Researchers studied the long-term disease control and late effects in pediatric patients with low-grade glioma (LGG) following radiotherapy (RT). In this single-institution study, >20 years post-RT survival was reported in over half of the children diagnosed with LGG; this report revealed the chronicity of toxicity beyond the typically reported follow-up. These data inform the therapeutic ratio of RT in this disease and may help guide late-effect screening recommendations.

• This study included 29 pediatric patients treated with photon-based RT for LGG from 1970 to 2004 (mean age at time of RT, 9.8 y; range, 0.6 to 19 y).
• Gross total resection was performed on 1 patient, subtotal resection or biopsy on 25, and 3 were treated based on radiographic characteristics alone.
• Prior to receiving RT, 3 patients underwent chemotherapy.
• The median RT dose was 54 Gy (range, 40 to 55 Gy).

• Data showed that the median follow-up was 17.8 years (range, 1.6 to 36.8 y) for all patients and 19.9 years (range, 1.6 to 36.8 y) for all living patients.
• Researchers found that the 5-, 10-, and 20-year local control and progression-free survival rates were equivalent at 82%, 74%, and 63%, respectively.
• They also noted that the 5-, 10-, and 20-year cause-specific survival and overall survival rates were equivalent at 89%, 85%, and 58%, respectively.
• An association of 'age below 4 years during treatment' with significantly inferior local control (P=0.0067), cause-specific survival (P=0.0021), and overall survival (P=0.0021) was demonstrated in univariate analysis.
• An analysis for late toxicity was carried out among 23 survivors, of those, 15 (65%) developed grade 3+ toxicity.
• Serious cognitive disability was documented as the most common Common Terminology Criteria for Adverse Events grade 3 toxicity (30% of survivors).
• Death of 4 patients (14%) secondary to treatment complications was reported, all occurring over a decade after completing RT.