Prognostic factors in metastatic rhabdomyosarcoma (RMS): The results of a pooled analyze from U.S. and European cooperative groups

Abstract

9542 Background: Prognosis factors on outcome for metastatic RMS are still matter of discussion. The analysis of a large cohort of patients can give arguments for development of risk-based therapy. Methods: We studied data from SIOP 84, SIOP 98, European Intergroup MMT89–91, Italian RMS4.99, IRS-III, -IV Pilot, -IV, -V, -D9501 to look at the influence of age, histology, sites of primary and metastatic disease, and number of sites of metastatic disease at the 3 year event-free survival. Results: 788 patients were included in the analyze and 776 in the multivariate analyse. The 3 year overall survival and EFS were 34% (se 1.7) and 27 % (se 1.6) respectively. By univariate analysis, 3-year EFS was significantly influenced by age 10 years or more (15% vs 36%), alveolar histology (28% vs 40%), location of primary tumor in unfavorable site -parameningeal, extremity and “other” sites- (31% vs 48%) the presence of three or more metastatic (17% vs 38%), the presence of bone or bone marrow involvement (24% vs 45%). By multivariate analysis, histology had no more impact on EFS. The EFS was strongly correlated to the number of the 4 other unfavorable prognostic factors: age, site of the primary, number of metastis sites, bone/bone marrow involvement relative risks were 1.6 for age (p<0.0001), 1.4 for site of primary tumor (p=0.002), 1.3 for bone/bone marrow involvement (p=0.005), 1.4 for number of metastatic sites (p=0.002). EFS was 58% for the 46 patients without any factors and was respectively 40%, 22%, 14% and 4% in patients with 1 factor (250 patients), 2 factors (233 patients), 3 factors (177 patients) or 4 factors (70 patients) (p<0.01). Conclusions: This analysis identified subsets of patients with very different outcomes. Patients with EFS less than 50% might be appropriate candidates for experimental approaches. No significant financial relationships to disclose.