As reported in The Lancet Oncology by Bonvalot et al, the phase III EORTC-62092 (STRASS) trial showed that the addition of preoperative radiotherapy to surgery did not improve abdominal recurrence–free survival in patients with primary retroperitoneal sarcoma.
In the open-label trial, 266 patients from 31 sites in 13 countries in Europe and North America were randomly assigned between January 2012 and April 2017 to receive preoperative radiotherapy plus surgery (n = 133) or surgery alone (n = 133). Radiotherapy consisted of 50.4 Gy in 28 daily fractions of 1.8 Gy in either 3D conformal radiotherapy or intensity-modulated radiotherapy (IMRT). The goal of surgery was a macroscopically complete resection of the tumor mass with en bloc organ resection as necessary. The primary endpoint was investigator-assessed abdominal recurrence–free survival in the intention-to-treat population.
Abdominal Recurrence–Free Survival
Median follow-up was 43.1 months. Overall, 128 patients (96%) in the surgery-alone group underwent surgery, and 119 patients (89%) in the radiotherapy group had both radiotherapy (IMRT in 95%) and surgery.
Median abdominal recurrence–free survival was 4.5 years (95% confidence interval [CI] = 3.9 years to not estimable) in the radiotherapy group vs 5.0 years (95% CI = 3.4 years to not estimable) in the surgery-alone group (hazard ratio [HR] = 1.01, 95% CI = 0.71–1.44, P = .95). Rates at 3 years were 58.7% vs 60.4%.
Metastasis-free survival at 3 years was 68.2% vs 68.3% (HR = 0.89, 95% CI = 0.58–1.36, P = .59). Median overall survival was not reached in either group (HR = 1.16, 95% CI = 0.65–2.05, P = .62), with 3- and 5-year rates of 84.0% vs 84.6% and 76.7% vs 79.4%, respectively.
The most common grade 3 or 4 adverse events in the radiotherapy group were lymphopenia (77% vs 1%), anemia (12% vs 8%), and hypoalbuminemia (12% vs 4%). Serious adverse events occurred in 24% vs 10% of patients. Death due to treatment-related serious adverse events occurred in one patient in the radiotherapy group (due to gastropleural fistula) and in no patients in the surgery-alone group.
The investigators concluded: “Preoperative radiotherapy should not be considered as standard of care treatment for retroperitoneal sarcoma.”
Sylvie Bonvalot, PhD, of the Institut Curie, Université Paris Sciences et Lettres, is the corresponding author for The Lancet Oncology article.
Disclosure: The study was funded by the European Organisation for Research and Treatment of Cancer and European Clinical Trials in Rare Sarcomas. For full disclosures of the study authors, visit thelancet.com.