Neoadjuvant Radiation Therapy Increases Adherence In Patients With High-risk Extremity Soft Tissue Sarcoma
*Hayley M. Dunlop1, *Ryan Zeh2, *Valerie P Grignol3, *Alex Kim3, *Carlo M. Contreras3, *Samilia Obeng-Gyasi3, Timothy M. Pawlik3, *Raphael E Pollock3, Joal D. Beane3
1The Ohio State University, College of Medicine, Columbus, OH;2University of Pittsburgh, Department of Surgery, Pittsburgh, PA;3The Ohio State University, Department of Surgical Oncology, Columbus, OH
OBJECTIVE(S): In addition to surgery, treatment for extremity soft tissue sarcoma (ESTS) should include radiation therapy (RT) for tumors that are high grade and >5 cm. Whether RT should be given in the neoadjuvant (NAT) versus adjuvant (AT) setting is controversial. The aim of this study was to determine if NAT improved adherence with RT compared to AT.
METHODS: Patients with ESTS diagnosed from 2004 through 2020 were identified in the National Cancer Database. The analytic cohort was restricted to patients with high grade tumors >5 cm in size without nodal or distant metastases who received limb-sparing surgery and RT with R0 margins. A multivariable logistic regression analysis identified factors associated with RT adherence, defined according to current guidelines as a dose of 50 Gy for NAT and a dose of 60 Gy for AT. A multivariable Cox Proportional Hazards model was used to assess overall survival.
RESULTS: A total of 2374 patients were evaluated, with 47.3% undergoing NAT (n=1123) and 52.7% (n=1249) undergoing AT. A greater proportion of patients treated with NAT (86.1%) were compliant with the recommended doses of RT when compared to patients treated with AT (69.4%, p<0.0001). A greater proportion of patients with private insurance (51.8% vs. 46.7%, p=0.027) received NAT, as did a greater proportion of patients at academic medical centers (68.0% vs. 56.6%, p<0.001). On multivariable analysis, patients who received AT were more likely to receive an insufficient dose of RT (OR 3.01 [95% CI 2.30-3.96]) as were those who underwent treatment in the South (OR 1.51 [1.05-2.19]) and the Midwest (OR 1.52 [1.02-2.27]). Neither RT adherence nor radiation sequencing (AT vs. NAT) were independent predictors of overall survival.
CONCLUSIONS: Patients who receive RT in the NAT setting are more likely to complete therapy and receive an optimal dose of RT compared to AT. Demographic disparities in receipt of NAT were observed, highlighting an opportunity to improve treatment in patients with high-risk ESTS.
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