Extremity sarcomas: an analysis of prognostic factors from the Intergroup Rhabdomyosarcoma Study III.

PURPOSE: Prognostic factors for extremity sarcomas have been reported previously, after analysis of Intergroup Rhabdomyosarcomas Studies (IRS) I and II. This report reviews the experience of IRS III (1984-1992), in light of these reported factors, and the pretreatment factors used in the staging system currently being evaluated in IRS IV. The results of treatment of extremity sarcomas in IRS III are reported.

METHODS: The charts of all patients entered in IRS III with an extremity-site tumor were reviewed. This group included patients with shoulder girdle and buttock sites. All patients were treated according to IRS III protocols. Survival rates were estimated by the method of Kaplan and Meier, and comparisons among groups of patients were made using a log-rank test. A multivariate analysis was performed to analyze all pretreatment factors that were significant by univariate analysis.

RESULTS: Of the 189 patients entered in IRS III with extremity sites, 88 (47%) had the most common alveolar histology. Fifty-nine patients were in group I at the time of presentation (completely resected disease), 48 in group II (microscopic residual disease), 36 in group III (gross residual disease), and 46 in group IV (metastatic disease). By univariate analysis, the significant prognostic factors affecting survival were clinical group, age at time of diagnosis, tumor size, distant metastases, nodal metastases, and local and distant recurrence. By multivariate analysis of pretreatment factors, age at time of diagnosis, nodal metastases, and distant metastases were significant prognostic factors affecting survival; tumor size approached significance. Both the clinical group system and pretreatment staging system (Lawrence/Gehan) predicted significant differences in survival between groups of patients. The lower survival rate among group II and III node-negative patients with a distal tumor (who, with more extensive surgery, could have been in group I) in comparison to group I patients with a distal lesion, approached significance. In patients without distant metastases, survival was significantly different in those patients that had negative nodes from those in whom nodes were not biopsied.

CONCLUSION: This review confirms that both clinical grouping and the new pretreatment staging system used in IRS IV can predict the likelihood of survival of children with extremity sarcomas. By multivariate analysis of the elements included in the staging system, nodal metastases, distant metastases, and tumor size were useful in predicting survival. In addition, age was a significant predictor. This study confirms previous suggestions that complete excision with gross and microscopically negative margins is preferable in the treatment of children with extremity rhabdomyosarcomas.