A prognostic model for soft tissue sarcoma of the extremities and trunk wall based on size, vascular invasion, necrosis, and growth pattern.

Abstract

In soft tissue sarcoma, better distinction of high-risk and low-risk patients is needed to individualize treatment and improve survival. Prognostic systems used in clinical practice identify high-risk patients based on various factors, including age, tumor size and depth, histological type, necrosis, and grade. Whole-tumor sections from 239 soft tissue sarcomas of the extremities were reviewed for the following prognostic factors: size, vascular invasion, necrosis, and growth pattern. A new prognostic model, referred to as SING (Size, Invasion, Necrosis, Growth), was established and compared with other clinically applied systems. Size, vascular invasion, necrosis, and peripheral tumor growth pattern provided independent prognostic information with hazard ratios of 2.2-2.6 for development of metastases in multivariate analysis. When these factors were combined into the prognostic model SING, high risk of metastasis was predicted with a sensitivity of 74% and a specificity of 85%. Moreover, the prognostic performance of SING compared favorably with other widely used systems. SING represents a promising prognostic model, and vascular invasion and tumor growth pattern should be considered in soft tissue sarcoma prognostication.