Factors predictive of mortality in pediatric extremity rhabdomyosarcoma

In order to examine factors predictive of fatal outcome in children presenting with histologically confirmed extremity rhabdomyosarcoma, we performed a retrospective analysis of our institutional experience from 1970 to 1985. Thirty-five patients were identified and staged according to international criteria (TNM). Variables evaluated for their predictive effect on fatal outcome included (1) tumor invasiveness, (2) tumor size, (3) anatomic location of the primary, (4) regional lymph node involvement, (5) distant metastases at presentation, (6) complete surgical resection, (7) use of amputation, and (8) alveolar histologic subtype. Significant predictors of mortality included (1) tumor invasiveness (P less than or equal to .0001), (2) regional node involvement (P less than or equal to .0002), (3) distant metastases at the time of presentation (P less than or equal to .001), (4) alveolar histology (P less than or equal to .001), (5) size of primary (P less than or equal to .007), and (6) completeness of surgical resection (P less than or equal to .05). In multivariate analysis, local tumor invasiveness was the most important predictor of fatal outcome with an associated relative risk of 18. We conclude that local tumor invasiveness is the most important determinant of clinical stage.