Trends in the Use of Adjuvant Chemotherapy for High-Grade Truncal and Extremity Soft Tissue Sarcomas.

BACKGROUND

In the randomized controlled trial (RCT) EORTC 62931, adjuvant chemotherapy failed to show improvement in relapse-free survival (RFS) or overall survival (OS) for patients with resected high-grade soft tissue sarcoma (STS). We evaluated whether the negative results of this 2012 RCT have influenced multidisciplinary treatment patterns for patients with high-grade STS undergoing resection at seven academic referral centers.

METHODS

The U.S. Sarcoma Collaborative database was queried to identify patients who underwent curative-intent resection of primary high-grade truncal or extremity STS from 2000 to 2016. Patients with recurrent tumors, metastatic disease, and those receiving neoadjuvant chemotherapy were excluded. Patients were divided by treatment era into early (2000-2011, pre-European Organisation for Research and Treatment of Cancer [EORTC] trial) and late (2012-2016, post-EORTC trial) cohorts for analysis. Rates of adjuvant chemotherapy and clinicopathologic variables were compared between the two cohorts. Univariate and multivariate regression analyses were used to determine factors associated with OS and RFS.

RESULTS

949 patients who met inclusion criteria were identified, with 730 patients in the early cohort and 219 in the late cohort. Adjuvant chemotherapy rates were similar between the early and late cohorts (15.6% versus 14.6%; P = 0.73). Patients within the early and late cohorts demonstrated similar median OS (128 months versus median not reached, P = 0.84) and RFS (107 months versus median not reached, P = 0.94). Receipt of adjuvant chemotherapy was associated with larger tumor size (13.6 versus 8.9 cm, P < 0.001), younger age (53.3 versus 63.7 years, P < 0.001), and receipt of adjuvant radiation (P < 0.001). On multivariate regression analysis, risk factors associated with decreased OS were increasing American Society of Anesthesiologists class (P = 0.02), increasing tumor size (P < 0.001), and margin-positive resection (P = 0.01). Adjuvant chemotherapy was not associated with OS (P = 0.88). Risk factors associated with decreased RFS included increasing tumor size (P < 0.001) and margin-positive resection (P = 0.03); adjuvant chemotherapy was not associated with RFS (P = 0.23).

CONCLUSIONS

Rates of adjuvant chemotherapy for resected high-grade truncal or extremity STS have not decreased over time within the U.S. Sarcoma Collaborative, despite RCT data suggesting a lack of efficacy. In this retrospective multi-institutional analysis, adjuvant chemotherapy was not associated with RFS or OS on multivariate analysis, consistent with the results from EORTC 62931. Rates of adjuvant chemotherapy for high-grade STS were low in both cohorts but may be influenced more by selection bias based on clinicopathologic variables such as tumor size, margin status, and patient age than by prospective, randomized data.

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