Adherence to stage-specific treatment guidelines and its effect on survival in stage IIA & IIB/IIIA extremity and trunk soft tissue sarcoma patients

The National Comprehensive Cancer Network (NCCN) has established evidence-based guidelines for the treatment of stage IIA & stage IIB/III extremity and superficial trunk soft tissue sarcomas (ETSTS). In this study, adherence to these guidelines, associated survival outcomes, and factors associated with receiving adherent therapy were examined. Stage IIA & IIB/III ETSTS patients (n=15,957) were identified from the National Cancer Data Base Participant Use File and categorized by treatment group (adherent vs. non-adherent). The Kaplan Meier estimator was used to calculate the survival curves for overall survival (OS) and disease-specific survival (DSS). Cox regression models were used to generate adjusted survival curves, and multivariate logistic regression models were built to determine factors associated with receiving non-adherent treatment. For stage IIA (n=5,734), 89.7% of patients received adherent treatment; adherent treatment patients experienced improved 5-year OS (78.0% vs. 57.3%), DSS (88.6% vs. 67.9%), and adjusted OS (82.5% vs. 66.0%). For stage IIB/III (n=10,223), 58.3% of patients received adherent treatment; adherent treatment patients experienced improved 5-year OS (59.7% vs. 45.6%), DSS (68.1% vs. 52.6%), and adjusted survival (60.9% vs. 44.6%). Non-academic treatment facilities, age ?75 years, and uninsured or unknown insurance status were significantly associated with non-adherent treatment for both stages. In stage IIB/III only, greater risk for non-adherent treatment was observed for females, Hispanics, those with Charlson scores \u3e0, those with government insurance, and those who traveled \u3e20 miles to a treatment facility. Odds of receiving adherent treatment improved 4% per year later diagnosed for stage IIA and trended towards 1% per year for stage IIB/III. In the Cox models, non-adherent treatment was associated with an increased risk of death both for stage IIA [HR=2.15, 95% CI: 1.87-2.48] and stage IIB/III [HR=1.63, 95% CI: 1.53-1.73]. Comprehensive treatment facilities and earlier year of diagnosis did not significantly increase the risk for mortality. However, for stage IIB/III, community centers were associated with increased mortality [HR=1.26, 95% CI: 1.11-1.43]. Overall, receiving adherent treatment was significantly associated with improved adjusted 5-year survival and a decreased risk of death. These results support adherence to NCCN guidelines in treating stage IIA & IIB/III ETSTS patients