Daniela Kandels, Torsten Pietsch, Brigitte Bison, Monika Warmuth‐Metz, Ulrich‐Wilhelm Thomale, Rolf‐Dieter Kortmann, Beate Timmermann, Pablo Hernáiz Driever, Olaf Witt, René Schmidt, Astrid K. Gnekow

• First‐line treatment of pediatric low‐grade glioma using surgery, radio‐ or chemotherapy fails in a relevant proportion of patients. We analyzed efficacy of subsequent surgical and nonsurgical therapies of the German cohort of the SIOP‐LGG 2004 study (2004‐2012, 1558 registered patients; median age at diagnosis 7.6 years, median observation time 9.2 years, overall survival 98%/96% at 5/10 years, 15% neurofibromatosis type 1 [NF1]). During follow‐up, 1078/1558 patients remained observed without (n = 217), with 1 (n = 707), 2 (n = 124) or 3 to 6First‐line treatment of pediatric low‐grade glioma using surgery, radio‐ or chemotherapy fails in a relevant proportion of patients. We analyzed efficacy of subsequent surgical and nonsurgical therapies of the German cohort of the SIOP‐LGG 2004 study (2004‐2012, 1558 registered patients; median age at diagnosis 7.6 years, median observation time 9.2 years, overall survival 98%/96% at 5/10 years, 15% neurofibromatosis type 1 [NF1]). During follow‐up, 1078/1558 patients remained observed without (n = 217), with 1 (n = 707), 2 (n = 124) or 3 to 6 (n = 30) tumor volume reductions; 480/1558 had 1 (n = 332), 2 (n = 80), 3 or more (n = 68) nonsurgical treatment‐lines, accompanied by up to 4 tumor‐reductive surgeries in 215/480; 265/480 patients never underwent any neurosurgical tumor volume reduction (163/265 optic pathway glioma). Patients with progressing tumors after first‐line adjuvant treatment were at increased risk of suffering further progressions. Risk factors were young age (<1 year) at start of treatment, tumor dissemination or progression within 18 months after start of chemotherapy. Progression‐free survival rates declined with subsequent treatment‐lines, yet remaining higher for patients with NF1. In non‐NF1‐associated tumors, vinblastine monotherapy vs platinum‐based chemotherapy was noticeably less effective when used as second‐line treatment. Yet, for the entire cohort, results did not favor a certain sequence of specific treatment options. Rather, all can be aligned as a portfolio of choices which need careful balancing of risks and benefits. Future molecular data may predict long‐term tumor biology.…