STREXIT2 · A PRAGMATIC CLINICAL STUDY OF NEOADJUVANT CHEMOTHERAPY FOLLOWED BY SURGERY VERSUS SURGERY ALONE FOR PATIENTS WITH HIGH RISK RETROPERITONEAL SARCOMA

Retroperitoneal sarcomas are rare diseases refractory to treatment with dismal prognosis. Surgery is the only standard approach to primary disease. We are proposing an innovative pragmatic approach supplementing a standard phase III clinical trial with an observational cohort. It is proposed to amend the ongoing phase III EORTC clinical trial STRASS2 investigating the added value of neoadjuvant chemotherapy before surgery for high-risk retroperitoneal sarcoma and to add an observational arm STREXIT2 that will capture real world data from patients not participating to STRASS2. We will compare the clinical outcomes between STRASS2 and STREXIT2 and explore the possible combination of STRASS2 and matched STREXIT2 patients to strengthen the results of the randomized clinical trial data and increase the power of subgroup analyses. If conclusive, the proposed research will help to understand the clinical added value and costs-effectiveness of neoadjuvant chemotherapy before surgery for high-risk retroperitoneal sarcoma. We will perform health economics analysis assessing the economic value of different treatment scenarios based on STRASS2 and STREXIT2. If successful, the outcomes of the project will define a new evidence-based standard of care for high-risk retroperitoneal sarcomas. The proposed research could lead to improved patient survival and quality of life but also improving health system sustainability. This is a multidisciplinary and multistakeholder consortium involving clinical oncologists, surgeons, health economists and patient representatives. The study design was successfully discussed with patients. This action is part of the Cancer Mission cluster of projects on Diagnosis and treatment.