N. Nagarajan1, J. Singh2, K. Giuliano1, F. Gani1, C. Wolfgang1, T. Pawlik3, E. Schneider4, J. Canner1, F. Johnston1, N. Ahuja5 1Johns Hopkins University School Of Medicine,Department Of Surgery,Baltimore, MD, USA 2Johns Hopkins Bloomberg School of Public Health,Baltimore, MD, USA 3The Ohio State University,Department Of Surgery,Columbus, OH, USA 4School of Medicine at the University of Virginia,Department Of Surgery,Charlottesville, VA, USA 5Yale University School of Medicine,Department Of Surgery,New Haven, CT, USA
Introduction:
Soft tissue sarcomas (STS) are heterogeneous tumors necessitating multipronged treatment approaches by multidisciplinary teams. However, the evidence for using radiation therapy in STS is variable. Therefore, we studied the association of radiation with survival in patients with STS.
Methods:
STS cases were identified in the Surveillance Epidemiology and End Results (SEER) Program (2002-2012) and categorized into 12 histological subtypes (ICD-O-3). Relative times to cause-specific mortality (censored at 10 years) were examined across patients undergoing surgery only, radiation only, or combination (surgery plus radiation accounting for interaction) using generalized gamma parametric survival functions stratified by histological subtype and controlling for age, sex, race, location, grade, size, local extension, lymph node and distant metastasis.
Results:
A total of 42,409 patients were included. Risk-adjusted survival analyses revealed that surgery alone was associated with significantly increased survival (1.9-5.9 times) compared to no treatment among all histological subtypes (p<0.05). Radiation alone was associated with significantly increased survival (1.4-2.5 times) in aggressive subtypes including leiomyosarcoma (p<0.05). Combination therapy was also associated with significantly increased survival (1.6-5.6 times) across all subtypes compared to no treatment (p<0.05). Compared to surgery alone, combination therapy showed incremental increases in survival for leiomyosarcoma, liposarcoma, angiosarcoma, and synovial sarcoma with only rhabdomyosarcoma showing statistically significant longer survival [Time Ratio:1.5 (95%CI:1.2-1.8),p=0.001](Figure).
Conclusion:
This study demonstrated that combination therapy is similar to surgery alone in most STS subtypes. Combination therapy with radiation appears to be beneficial in aggressive subtypes of STS with up to 50% incremental increase in survival compared to surgery alone.
