Comparison of different systemic therapeutic regimes in resectable soft-tissue sarcoma—results of a network meta-analysis

Background: The standard treatment of high-risk soft-tissue sarcoma consists of surgical resection followed by risk-adapted radiation therapy. Further treatment options that may improve local and systemic tumor control, including chemotherapy, are not well established. Due to the heterogeneity of the disease, different systemic approaches as well as their application at different time points have been attempted. Methods: We conducted a systematic literature search for randomized clinical trials in the treatment of localized, resectable high-risk adult soft-tissue sarcoma comparing different treatment modalities according to the PRISMA guidelines. We extracted published hazard ratios and number of events for the endpoints overall and disease-free survival (OS; DFS) as well as local and distant recurrence-free interval (LRFI; DRFI). The different modalities were compared in a network meta-analysis against the defined standard treatment surgery ± radiotherapy using the inverse-variance heterogeneity model. Results: The literature search identified 25 trials including 3453 patients. Five different treatment modalities were compared in the network meta-analysis. The addition of adjuvant chemotherapy significantly improved OS compared to surgery ± radiotherapy alone (HR = 0.86; CI-95%: 0.75–0.97; p = 0.017). Likewise, neoadjuvant chemotherapy combined with regional hyperthermia (naCTx + HTx) also led to superior OS (HR = 0.45; CI-95%: 0.20–1.00; p = 0.049). Both neoadjuvant chemotherapy alone (naCTx) and perioperative chemotherapy (periCTx) did not improve OS (HR = 0.61; CI-95%: 0.29–1.29; p = 0.195 and HR = 0.66; CI-95%: 0.30–1.48; p = 0.317, respectively). Histology-tailored chemotherapy (htCTx) also did not improve survival compared to surgery ± radiotherapy (HR = 1.08; CI-95%: 0.45–2.61; p = 0.868). The network analysis of DFS, LRFI, and DRFI revealed a similar pattern between the different treatment regimens. Adjuvant chemotherapy significantly improved DFS, LRFI, and DRFI compared to surgery ± radiotherapy. In direct comparison, this advantage of adjuvant chemotherapy was restricted to male patients (HR = 0.78; CI-95%: 0.65–0.92; p = 0.004) with no effect for female patients (HR = 1.08; CI-95%: 0.90–1.29; p = 0.410). Conclusions: Standardized chemotherapy in high-risk soft-tissue sarcoma appears to be of added value irrespective of timing. The benefit of adjuvant chemotherapy seems to be restricted to male patients. The addition of regional hyperthermia to neodjuvant chemotherapy achieved the best effect sizes and might warrant further investigation.