Enrico Martin

58 Chapter 3 Figure 3 Conditional inference tree of overall survival in localized non-retroperitoneal adult MPNSTs. Predictors for survival in localized non-retroperitoneal MPNST On multivariate analysis age 60+ years, lesions in NF1 patients, large (>5cm) and deep- seated tumors were significantly associated with a poor survival in localized non- retroperitoneal MPNSTs (all p<0.05, Figure 4 and 5 ). Tumor site, Triton tumors, and time period of diagnosis were not significantly associated with survival (all p>0.05). There was a trend for MPNSTs arising within neurofibromas to be associated with increased survival (p ≈ 0.08). Surgical margins were the only treatment related factor significantly associated with survival. Both R2 resections and biopsies only were significantly associated with worse survival (both p<0.05). R1 resections were not significantly associated with worse survival compared to R0 (p>0.05). Both the use of radiotherapy and chemotherapy were not independently associated with survival (both p>0.05). Survival and predictors for survival in localized retroperitoneal MPNST Retroperitoneal MPNSTs had a significantly worse outcome: median survival of 1.1 years compared to 6.0 years in patients with MPNST in other tumor sites (p<0.05, Figure 2D ). The multivariate model for retroperitoneal MPNST specifically showed that older age and R2 and no resections were also associated with poorer survival in this subset of MPNSTs (both p<0.05, Figure 6 ). Additionally, male gender was significantly associated with poorer survival (p<0.05), without any known demographical differences compared to their female counterparts. Both radiotherapy and chemotherapy use were not significantly associated with survival (p>0.05).