Enrico Martin

56 Chapter 3 Table 2 Treatment of localized MPNST in adults. Surgically treated Variable Overall nRP MPNST RP MPNST P Surgical Margin R0 306 (55.2%) 294 (55.8%) 12 (44.4%) 0.180 R1 127 (22.9%) 118 (22.4%) 9 (33.3%) R2 28 (5.1%) 26 (4.9%) 2 (7.4%) Unknown margin 93 (16.8%) 89 (16.9%) 4 (14.8%) Radiotherapy Sequence No Radiotherapy 313 (55.8%) 295 (55.0%) 19 (70.4%) 0.044 Preoperative Radiotherapy 28 (5.1%) 25 (4.7%) 3 (11.1%) Postoperative Radiotherapy 213 (39.2%) 208 (40.2%) 5 (18.5%) Chemotherapy No 517 (93.3%) 495 (93.9%) 22 (81.5%) 0.012 Yes 37 (6.7%) 32 (6.1%) 5 (18.5%) Biopsy only Radiotherapy No 50 (66.7%) 43 (64.2%) 7 (87.5%) 0.26 Yes 25 (33.3%) 24 (35.8%) 1 (12.5%) Chemotherapy No 57 (76.0%) 52 (77.6%) 5 (62.5%) 0.39 Yes 18 (24.0%) 15 (22.4%) 3 (37.5%) MPNST: malignant peripheral nerve sheath tumor, nRP: non-retroperitoneal, RP: retroperitoneal Survival in localized non-retroperitoneal MPNST Overall estimated median survival of localized non-retroperitoneal MPNSTs was 6.0 years. Median survival of patients older than 60 was 4.5 years compared to 14.5 years in their younger counterparts (p<0.05, Figure 2 ). The median survival of R0 resections was 14.7 years, 5.8 years in R1, and less than a year in R2 and unresected patients (p<0.05). Although median survival of NF1 patients was shorter compared to non-NF1 patients (3.2 vs. 6.4 years respectively), this difference was not statistically significant (p>0.05). MPNSTs arising within neurofibromas had a significantly longer median survival of 14.4 years compared to 5.3 years in patients with de novo neoplasms (p<0.05). Time period of diagnosis was not significantly different (p>0.05), yet a trend is seen in longer survival for cases presenting after 2005 (7.5 vs. 5.2 years). The conditional inference tree found resectability (R0/R1) to be the strongest predictor for survival in any localized adult non-retroperitoneal MPNST (p<0.05, Figure 3 ). Whenever R0 or R1 resections were performed, patient age was the most significant factor associated with survival (p<0.05). In older patients (60+ years) with at least an R1 resection only tumor depth was significantly associated with survival (p<0.05). In younger adults (<60 years) larger tumor