Enrico Martin

76 Chapter 4 Table 3 Treatment of localized pediatric MPNST. Variable Overall Non-NF1 NF1 P Surgery Surgical excision 58 (90.6%) 36 (94.4%) 22 (84.6%) 0.21 Biopsy only 6 (9.4%) 2 (5.6%) 4 (15.4%) Surgical Margin R0 32 (59.3%) 20 (60.6%) 12 (57.1%) 0.53 R1 15 (27.8%) 10 (30.3%) 5 (23.8%) R2 1 (1.9%) 1 (3.0%) 0 (0.0%) Biopsy only 6 (11.1%) 2 (6.0%) 4 (19.0%) Resection, unknown margin 10 5 5 Radiotherapy Sequence No Radiotherapy 40 (62.5%) 26 (68.4%) 14 (53.8%) 0.44 Preoperative Radiotherapy 5 (7.8%) 2 (5.3%) 3 (11.5%) Postoperative Radiotherapy 19 (29.7%) 10 (26.3%) 9 (34.6%) Chemotherapy No 42 (65.6%) 23 (60.5%) 19 (73.1%) 0.42 Yes 22 (34.4%) 15 (39.5%) 7 (26.9%) Chemotherapy Sequence No Chemotherapy 42 (65.6%) 23 (60.5%) 19 (73.1%) 0.64 Preoperative Chemotherapy 8 (12.5%) 5 (13.2%) 3 (11.5%) Postoperative Chemotherapy 12 (18.8%) 9 (23.7%) 3 (11.5%) Chemotherapy only 2 (3.1%) 1 (3.0%) 1 (3.8%) MPNST: malignant peripheral nerve sheath tumor, NF1: neurofibromatosis type 1 Treatment of localized pediatric MPNST Overall, surgical excision was part of initial treatment in 90.6% of localized pediatric MPNSTs ( Table 3 ). R0 resections were achieved in 66.7%, without any differences between NF1 and non-NF1 patients (p>0.05). R1 resections were achieved in 31.3% and only one child had an R2 margin as final surgical margin. Radiotherapy was administered in 37.5% of all patients, but not more commonly in NF1 patients (47.2% vs. 31.6%, p>0.05). No patient received salvage radiotherapy only. Chemotherapy was administered in 34.4% as an adjunct to surgical excision, of which 40% was administered in a neoadjuvant setting. Rates of chemotherapy use were non-significantly higher in non-NF1 patients (39.5% vs. 26.9%, p>0.05). Two patients received chemotherapy without any further surgical excision. No patient received both adjuvant and neoadjuvant chemotherapy. Survival and factors associated with survival in pediatric MPNST In the complete nationwide cohort, the estimated 5-year survival rate of any pediatric MPNST was 62.0% (SE: 5.9%) compared to 46.2% (SE: 1.9%) in adult MPNST (p<0.05). In localized disease only, 5-year survival rates were 66.3% (SE: 6.0%) and 51.6% (SE: 2.1%) respectively (p<0.05). Pediatric patients initially presenting with metastatic