Toward Better Soft Tissue Sarcoma Staging: Building on American Joint Committee on Cancer Staging Systems Versions 6 and 7

Background

Based on review of patient data in case conferences over time, we hypothesized that clinically relevant data are omitted in routine soft tissue sarcoma staging.

Methods

We examined subsets of a prospectively collected single institution soft tissue sarcoma database with respect to criteria of the AJCC versions 6 (2002) and 7 (2010) staging systems and examined their clinical outcomes.

Results

Relapse-free survival decreases with increasing primary tumor size in four categories, versus two categories used in AJCC 6 and 7 staging. Disease-specific survival decreases over three categories. Conversely, omission of tumor depth as a prognostic factor in version 7 appears supported, since tumor depth is not an independent risk factor for disease-specific survival by multivariate analysis. Patients with nodal disease and no other metastases fare better than patients with other metastases, but have inferior outcomes compared with patients with large high-grade tumors without nodal metastasis. Multivariate analysis identified size, site, grade, age, nodal metastatic disease, and other metastatic disease as independent risk factors for disease-specific survival. Versions 6 and 7 criteria are tacit regarding anatomic site and histology for tumors with identical FNCLCC grade.

Conclusions

Improved patient risk assessment may be achieved by staging using a larger number of size categories. Staging system refinements come at the cost of a larger number of staging categories. Histology or site-specific staging systems, nomograms or Bayesian belief networks may provide more accurate means to assess clinical outcomes.