Purpose: To define the optimal initial management and the best extent of surgery that would optimize margins on primary retroperitoneal sarcomas (RPS). Patients and Methods: A total of 382 patients with primary RPS were analyzed. Sixty-five patients had a simple resection of the tumor, 120 patients had a complete compartmental resection (systematic resection of noninvolved contiguous organs), 130 patients had a contiguously involved organ resection, 21 patients had a systematic re-excision, 38 patients had an incomplete gross resection, and eight patients had a biopsy alone. Radiotherapy and chemotherapy were administered to 121 and 145 patients, respectively. Results: One, 3-, and 5-year overall survival (OS) rates were 86% (95% CI, 0.82 to 0.89), 66% (95% CI, 0.61 to 0.71), and 57% (95% CI, 0.51 to 0.62), respectively. Median overall survival was 6 years. In the multivariate analysis, high grade, tumor rupture, gross residual disease, and positive margins were associated with decreased OS. Low grade, no tumor rupture, negative histologic margins, a high number of patients undergoing operation per center, and compartmental resection compared with standard procedures were associated with decreased abdominal recurrences. Compartmental resection is a significant variable, predicting a 3.29-fold lower rate of abdominal recurrence compared with simple complete resection. Conclusion: Complete compartmental surgery without tumor rupture should be performed when possible to achieve clear margins. This surgery should be performed in a high-volume center. The role of adjuvant treatments should be evaluated in a randomized trial in association with this optimal surgery.

Iron catalyses the oxidation of lipids in biological membranes and promotes a form of cell death called ferroptosis¹. Defining where this chemistry occurs in the cell can inform the design of drugs capable of inducing or inhibiting ferroptosis in various disease-relevant settings. Genetic approaches have revealed suppressors of ferroptosis^2,3,4; by contrast, small molecules can provide spatiotemporal control of the chemistry at work⁵. Here we show that the ferroptosis inhibitor liproxstatin-1 exerts cytoprotective effects by inactivating iron in lysosomes. We also show that the ferroptosis inducer RSL3 initiates membrane lipid oxidation in lysosomes. We designed a small-molecule activator of lysosomal iron—fentomycin-1—to induce the oxidative degradation of phospholipids and ultimately ferroptosis. Fentomycin-1 is able to kill iron-rich CD44^high primary sarcoma and pancreatic ductal adenocarcinoma cells, which can promote metastasis and fuel drug tolerance. In such cells, iron regulates cell adaptation^6,7 while conferring vulnerability to ferroptosis^8,9. Sarcoma cells exposed to sublethal doses of fentomycin-1 acquire a ferroptosis-resistant cell state characterized by the downregulation of mesenchymal markers and the activation of a membrane-damage response. This phospholipid degrader can eradicate drug-tolerant persister cancer cells in vitro and reduces intranodal tumour growth in a mouse model of breast cancer metastasis. Together, these results show that control of iron reactivity confers therapeutic benefits, establish lysosomal iron as a druggable target and highlight the value of targeting cell states¹⁰.