Extremity Soft Tissue Sarcoma: A Multi-Institutional Validation of Prognostic Nomograms.

Area of Science:

• Oncology
• Surgical Oncology
• Biostatistics

Background:

• Prognostic nomograms aid in predicting outcomes for patients with extremity soft tissue sarcoma (STS).
• The Sarculator and Memorial Sloan Kettering (MSKCC) nomograms are established tools for STS prognostication.
• Validation in large, contemporary cohorts is crucial for assessing nomogram reliability.

Purpose of the Study:

• To externally validate the prognostic accuracy of the Sarculator and MSKCC nomograms.
• To assess the nomograms' ability to predict overall survival (OS), distant metastases cumulative incidence (DMCI), and disease-specific survival (DSS) in a large cohort.
• To evaluate the performance of these nomograms in a modern, multi-institutional setting.

Main Methods:

• A cohort of 1326 patients with resected primary extremity STS from 2000-2017 across nine institutions was analyzed.
• Sarculator and MSKCC nomograms were used to calculate predicted survival probabilities and cumulative incidences.
• Calibration plots and Harrell's concordance index (C-index) were employed to assess prognostic accuracy and discriminative ability.

Main Results:

• The cohort comprised predominantly undifferentiated pleomorphic sarcoma (35%) with a median tumor size of 8.0 cm and high-grade tumors (78%).
• Both nomograms demonstrated good prognostic ability: C-indices for OS ranged from 0.72-0.73, and for DSS, it was 0.71.
• Calibration plots indicated good agreement between predicted and observed survival outcomes for OS, DMCI, and DSS.

Conclusions:

• The Sarculator and MSKCC nomograms are reliable tools for predicting survival and recurrence in patients with resected extremity STS.
• External validation in this large, multi-institutional cohort supports the continued use of these nomograms in clinical decision-making.
• These findings reinforce the value of nomograms for personalized risk assessment in extremity STS management.