Comparative study of the National Cancer Institute and French Federation of Cancer Centers Sarcoma Group grading systems in a population of 410 adult patients with soft tissue sarcoma

Abstract

Purpose: Several histologic grading systems have been validated in soft tissue sarcomas (STS), but no system is currently accepted worldwide. The National Cancer Institute (NCI) and French Federation of Cancer Centers Sarcoma Group (FNCLCC) systems were examined comparatively in the same population of patients with STS to determine which system is the best prognosticator with regard to metastasis development and tumor mortality.

Patients and methods: Four hundred ten adult patients with nonmetastatic STS were examined. Histologic grade was established according to the NCI and FNCLCC systems in each case. The prognostic value of both systems was examined using univariate and multivariate (Cox's model) analyses, and special attention was devoted to tumors with discordant grades.

Results: In univariate analysis, both the NCI and FNCLCC systems were of prognostic value to predict metastasis development and tumor mortality. In multivariate analysis, high-grade tumors, irrespective of the system used, size > or = 10 cm, and deep location were found to be independent prognostic factors for the advent of metastases. Tumor grade had a higher predictive value than size or depth, and higher prognostic weight was assigned to the FNCLCC grading system in Cox models. Grade discrepancies were observed in 34.6% of the cases. An increased number of grade 3 STS, a reduced number of grade 2 STS, and a better correlation with overall and metastasis-free survival within subpopulations with discordant grades were observed in favor of the FNCLCC system.

Conclusion: The FNCLCC system showed slightly increased ability to predict distant metastasis development and tumor mortality. The use of this system to evaluate STS aggressiveness might be favored.