National evaluation of patterns and predictors of underuse of multimodal therapy for high-risk extremity soft tissue sarcoma

Background: Treatment of high-risk extremity soft tissue sarcomas remains widely varied. Despite growing support for a multimodal approach for treatment of these rare and aggressive neoplasms, its dissemination remains underused. This national study aimed to evaluate variations in treatment patterns and uncover factors predictive of underuse of multimodal therapy in high-risk extremity soft tissue sarcomas. Methods: The 2010 to 2015 National Cancer Database was used to evaluate trends in 3 common treatment patterns: surgery alone, surgery + adjuvant therapy, and neoadjuvant therapy + surgery. Demographic-, sarcoma-, hospital-, and treatment-level factors of 6,725 surgically treated patients with stage II or III intermediate- to high-grade extremity soft tissue sarcomas were evaluated by types of treatment modality. Stepwise multivariable logistic regression was performed to identify factors predictive of each treatment modality. Results: When compared to surgery alone (34.6%) and adjuvant therapy (41.2%), use of neoadjuvant therapy + surgery for high-risk extremity soft tissue sarcomas remained low (25.3%). However, time trend analysis demonstrated that neoadjuvant therapy + surgery has significantly increased by 7% per year, whereas surgery alone decreased by 4% every year (P < .05 for both). Factors predictive of surgery alone were older age, nonprivate insurance, increasing travel distance, and multimorbidity (P < .05). Conversely, factors associated with neoadjuvant therapy + surgery were private insurance, higher education, and care at academic or high-volume institutions (for all, P < .05). Tumor-related factors predictive for neoadjuvant therapy + surgery included size <5 cm and higher-grade tumors (P < .05). Conclusion: Adoption of multimodality therapy for high-risk extremity soft tissue sarcomas remains low and gradual in the United States. Dissemination of multimodality therapy will require attention to access and hospital factors to maximize these therapies for high-risk extremity soft tissue sarcomas.