Two nomograms are reliable prognostic methods that can be used to predict overall survival and distant metastases in patients following surgical resection of soft-tissue sarcoma of the extremities, according to an article published in The Lancet Oncology.1
They can be used to strengthen prognosis-based decision making, enhance patient stratification, and inform patients.
The American Joint Committee on Cancer/Union for International Cancer Control staging system does not have enough details to encompass the multitude of soft-tissue sarcomas and prognostic methods need refinement. Therefore, investigators sought to develop and externally validate 2 predictive nomograms in this patient population.
The development cohort (N = 1452) was made up on consecutive patients who had an operation at the Istituto Nazionale Tumori in Milan, Italy, between 1994 and 2013. The external validation cohorts were made up of 3 cohorts of patient data from 420 patients treated at the Institut Gustave Roussy in France from 1996 to 2012, 1436 patients at Mount Sinai Hospital in Toronto, Canada from 1994 to 2013, and 444 patients treated at the Royal Marsden Hospital in London, England, from 2006 to 2013.
Results showed that the 10-year overall survival rate in the development cohort was 72.9% (95% CI, 70.2 – 75.7) and 10-year crude cumulative incidence of distant metastases was 25.0% (95% CI, 22.7 – 27.5).
For the overall survival nomogram, the variables selected applying a backward procedure in the multivariable Cox model (age, tumor size, Federation Francaise de Centres de Lutte Contre le Cancer grade, and histologic subtype) showed a significant effect on survival.
The same variables except age were used for the distant metastases nomogram. The Harrell C index for overall survival was 0.767 (95% CI, 0.743 – 0.789) in the developmental cohort and distant metastases was 0.759 (95% CI, 0.736 – 0.781).
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The Harrell C index for overall survival and distant metastases in the validation cohorts were 0.698 (95% CI, 0.638 – 0.754) and 0.652 (95% CI, 0.605 – 0.699; French), 0.775 (95% CI, 0.754 – 0.796; British) and 0.744 (0.720 – 0.768; Canadian), and 0.762 (95% CI, 0.720–0·806) and 0.749 (95% CI, 0.707 – 0.791; British).
“The two nomograms both performed well in terms of discrimination (ability to distinguish between patients who have had an event from those who have not) and calibration (accuracy of nomogram prediction) when applied to the validation cohorts,” the authors wrote.
- Callegaro D, Miceli R, Bonvalot S, et al. Development and external validation of two nomograms to predict overall survival and occurrence of distant metastases in adults after surgical resection of localised soft-tissue sarcomas of the extremities: a retrospective analysis [published online ahead of print April 5, 2016]. Lancet Oncol. doi: 10.1016/S1470-2045(16)00010-3.