Radiotherapy Remains Underutilized in the Treatment of Soft-Tissue Sarcomas: Disparities in Practice Patterns in the United States

Abstract

Practice patterns in the use of radiation therapy (RT) for soft tissue sarcoma (STS) remains quite variable, despite national guidelines recommending the addition of radiotherapy to surgery for patients with high grade STS. Furthermore, treatment with neoadjuvant RT can reduce many late RT toxicities. Likewise, the use of intensity modulated radiation therapy (IMRT) can reduce both early and late radiation-induced toxicities. Using the National Cancer Database (NCDB), we assessed patterns of care in regards to variations in overall radiotherapy use, preoperative versus postoperative treatment, and specific RT modalities in this population. Patients aged 18 years or older with stage II/III STS treated with limb-sparing surgery and radiation therapy from 2004 through 2015 were identified from the NCDB. Patterns of care were assessed using multivariable logistic regression analysis. Of 27,426 total patients, 11,654 (42%) were treated with surgery alone versus 15,772 (58%) with RT in addition to surgery, with no overall increase in RT use noted over the study period. Notable predictors of receipt of RT include larger tumor size (>5 cm), Grade III tumors, and tumors located in the extremity. Conversely, female gender, older age (≥ 70), African American race, insurance status, farther distance to treatment, and poor performance status were negative predictors of perioperative radiotherapy use. Of those receiving RT, 27% were treated neoadjuvantly and 73% were treated adjuvantly. The proportion of those receiving neoadjuvant vs. adjuvant RT increased over time. Relevant factors associated with neoadjuvant radiation include treatment at academic centers, larger tumors, and tumors located in the extremity. In addition, of those who received RT with modality specified as IMRT or 3D conformal RT (3DCRT), 61% were treated with IMRT and 39% were treated with 3DCRT. The proportion of those treated with IMRT increased with time. Relevant factors associated with IMRT use include treatment at academic centers, commercial insurance, larger tumors, and tumors arising in non-extremity locations (head and neck, thorax, and abdomen/pelvis). In this observational cohort study using the NCDB, we noted that a significant number of patients are not receiving guideline-concordant care. Our findings also note potential sociodemographic disparities that may be contributing to variations in practice patterns and highlight the concern that not all patients may be equally benefiting from available therapies for STS.