Development of a radiomic signature to predict overall survival probabilities of patients affected by soft-tissue sarcomas of the extremities and trunk wall
Author Block: A. Vanzulli, G. Tinè, A. Messina, C. Morosi, R. Miceli, S. Stacchiotti, A. Gronchi, S. Pasquali, D. Callegaro; Milan/IT
Purpose: Soft-tissue sarcomas of the extremities and trunk wall (ESTS) are characterized by heterogeneous clinical behaviour.
Surgery is the standard-of-care, with peri-operative chemotherapy in patients at high risk for recurrence, namely those with a predicted overall survival (pOS) <60% according to validated nomograms such as Sarculator.
Methods or Background: Tumours were manually annotated on pre-operative MRI of 91 patients with primary ESTS who underwent surgery (2011-2015).
A total of 2144 radiomic features pertaining to First Order and GLCM categories were extracted with a customized tool (Corino, 2018) and a Laplacian filter was applied to retain those explaining ≥ 80% of dataset variance (n = 168).
The selected radiomic features were then combined into a prognostic radiomic signature (RS) applying a customized version of the Bayesian Lasso adapted for survival regression.
Accuracy was evaluated with the 5-year AUC and C-index, while calibration was assessed using the 5-year Brier Score (BS).
Results or Findings: Median tumor diameter was 8 cm (5-10.8). Tumor malignancy grade was G1, G2 and G3 in 22(24,2%) 21(23.1%) G2 and 48 (52.7%) patients, respectively.
The following tumor histologies were identified: 8.8%LMS, 26.4%UPS, 8.8%DDPLPS, 18.7%MLPS, 3.3%MPNST, 22%MFS, 4.4%SS, 7.6%Other.
The median follow-up was 55.8 months (IQR, 44.8-72.9).
19 patients had a pOS <60%.
The RS demonstrated excellent predictive accuracy (5-year AUC: 0.883, 95% CI 0.828-0.927; C-index: 0.840, 95% CI 0.791-0.878) and calibration (5-year BS: 0.376, 95% CI: 0.337-0.412) for stratifying patients’ OS and was significantly associated with Sarculator’s risk groups, with RS values 39.6% higher in the low-pOS compared to the high-pOS group (p=0.001).
Conclusion: Radiomics may be employed to stratify ESTS patients at diagnosis - unlike commonly employed nomograms, which are utilized after resection and definitive histopathological examination - and orient clinical management.
Limitations: External validation pending
Funding for this study: Nothing to disclose
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: Not applicable