Posters— Radiation Oncology

MALIGNANT PERIPHERAL NERVE SHEAT TUMORS (MPNST): A RETROSPECTIVE ANALYSIS ON 125 PATIENTS

D. Voican, C. Billard, P. Terrier, S. Bonvalot, V. Vanel, C. Le Péchoux, G. Missenard, MC. Le Deley and A. Le Cesne, Soft Tissue Sarcoma Unity, Institut Gustave Roussy (IGR), Villejuif 94805. France

Purpose: to evaluate the prognostic factors in adult patients (pts) with initial localized MPNST.

Patients: between 1980 and 1997, 125 pts were treated at IGR. Surgery of primary tumor was performed in all cases. A complete resection was achieved in 84% of pts. Adjuvant chemotherapy and radiotherapy were given in 33% and in 42% of pts respectively. The median age of pts was 39 yrs (15 to 77 yrs). Tumor sites were as follows : extremity 31%, thorax 21%, abdomen 22%, head and neck 18% and pelvis 9%. The median tumor size was 9 cm (range I to 30 cm). Neurofibromatosis type I (NFI) is present in 20% of pts.

Results: Median follow-up time was 9 years (3 to 25). Relapses were observed in 69% of pts (local 56%, distant 19%, both 25%). The 5-yr and 8-yr overall survival were 50% and 42% respectively. High histologic grade, tumor size > 10 cm, NF1 association, non extremity tumors and primary incomplete resection are unfavorable prognostic factors for overall survival in univariate analysis. High grade MPNST, non extremity tumors and NF1 phenotype are correlated to overall survival in multivariate analysis. A high treatment-related morbidity was observed in NFI pts with MPNST.

Conclusion: optimal resection seems to be the best predictive parameter for a favorable outcome in localized MPNST. Adjuvant treatments are recommended in pts with high grade locally advanced MPNST.