Predictive Value of Grade for Metastasis Development in the Main Histologic Types of Adult Soft Tissue Sarcomas: a Study of 1240 Patients from the French Federation of Cancer Centers Sarcoma Group

Background: Histologic grade is said to be the most important prognostic factor in adult soft tissue sarcomas (STS), but most grading systems have been tested in the overall sarcoma group and the predictive value of histologic grade needs to be assessed specifically for each of the histologic categories.

Methods: From 1980 to 1994, 1240 nonmetastatic patients were entered in the French STS database. The following parameters were studied: patient's age and gender, previous history, tumor location, size and depth, neurovascular or bone involvement (NBI), histologic type and subtype, and grade (the French Federation of Cancer Centers [FNCLCC] system). Median follow-up for the survivors was 88 months; only 5% of patients were lost to follow-up. The authors performed univariate and multivariate analyses for metastasis-free survival for the overall sarcoma group and for every main histologic type.

Results: In order of importance, parameters were respectively retained as independent predictors of metastasis as follows: grade, tumor size, NBI and tumor depth for the overall group, grade and NBI for malignant fibrous histiocytomas (n = 349), tumor size, histologic subtype and grade for liposarcomas (n = 188), NBI, grade and tumor size for leiomyosarcomas (n = 148), grade and NBI for synovial sarcomas (n = 125), grade for unclassified sarcomas (n = 140), and sarcomas of other types (n = 158). No parameter was significant for malignant schwannomas (n = 72) or for rhabdomyosarcomas (n = 60).

Conclusion: In this study, histologic grade appeared as an independent predictor of metastasis development in the main histologic types of adult STS, with the exception of malignant schwannomas and rhabdomyosarcomas.