Children <1 year show an inferior outcome when treated according to the traditional LGG treatment strategy: a report from the German multicenter trial HIT-LGG 1996 for children with low grade glioma (LGG)

Background: Children diagnosed with LGG at an age <1 year are reported to have an impaired prognosis in comparison to older patients. Analysis of this subgroup could reveal the necessity to develop risk-adapted treatment approaches.

Procedure: Children <1 year at diagnosis (n = 66, median age 7.3 months, 33 female, none NFI) from the HIT-LGG 1996 cohort were analyzed for risk factors for EFS, PFS and OS. Several children suffered from diencephalic syndrome (DS, n = 22) and primary dissemination (DLGG, n = 9), 50 had a supratentorial midline (SML) location. Extent of resection was complete/subtotal in 12, partial in 15, biopsy in 27. Tumors were pilocytic astrocytoma WHO grade I (n = 33), other WHO grade I (n = 14), pilomyxoid astrocytomas WHO grade II (n = 3), and neuroepithelial tumors WHO grade II (n = 4).

Results: One-year EFS was 34.8%. SML-localisation, minor extent of surgery, pilocytic astrocytoma, DLGG and DS were unfavorable predictive factors. No additional non-surgical therapy was applied in 24, 36 were treated with VCR/carboplatin chemotherapy, 6 with radiotherapy (5/6 brachytherapy). Ten-year-PFS-rate following non-surgical therapy was 16.7%; DS and DLGG were unfavorable factors. Ten-year-OS-rate was 72.8%, lower for children <6 months at diagnosis, with DS, or with DLGG. At last follow up in August 2011, vision in 31 living children was often severely impaired.

Conclusions: Children <1 year at diagnosis have a conspicuously impaired survival with current treatment approaches. Age <6 months, diencephalic syndrome and dissemination constitute risk factors for even lower PFS and OS. Treatment adaptations are needed to improve outcome and molecular genetics may explain tumor aggressiveness.