Now Enrolling: The STRASS 2 study is testing a new treatment approach for patients with high-risk retroperitoneal sarcoma

Sarcoma is a rare disease, making up about 1% of all cancers that occur in adults. There are two main types—soft tissue or bone sarcoma—and more than 70 subtypes. Retroperitoneal sarcomas (RPS) are soft tissue sarcomas that develop in the abdomen and pelvis, behind the abdominal lining and near the kidneys.

The usual approach to treating RPS is surgery. However, researchers think there may be a role for chemotherapy or radiation therapy, in addition to surgery. Until recently, researchers were not able to study these approaches because RPS is so rare, and finding enough patients to conduct a randomized clinical trial was difficult.

Thanks to a global collaboration between research organizations in recent years, a trial called STRASS successfully reached its enrollment goal. STRASS showed that the use of radiation prior to surgery did not benefit patients with RPS. This was likely because the study included both patients who were at risk of the sarcoma spreading only in a limited area and patients who were at risk of the sarcoma spreading to distant areas of the body. Radiation therapy would not be effective for this second group, because it only treats the original area where the sarcoma started.

A key question that came from these results is whether chemotherapy might help patients with RPS who are determined to be at risk of their cancer growing fast and being likely to spread to distant areas of the body (doctors refer to these patients as being at high risk). To answer this, researchers in the ECOG-ACRIN Cancer Research Group (ECOG-ACRIN) are collaborating with researchers worldwide on the STRASS 2 trial. STRASS 2 is testing if treatment with chemotherapy before surgery reduces the chance of the cancer spreading. The primary endpoint is disease-free survival.

STRASS 2 is the second randomized study ever performed in retroperitoneal soft tissue sarcoma and the first to activate from the ECOG-ACRIN Sarcoma Working Group, formed in 2020. The trial is open in Europe, Canada, Australia, New Zealand, Japan, and now the United States through ECOG-ACRIN. STRASS 2 will enroll a total of 250 patients across these countries. Participants will be randomized to receive either three cycles of chemotherapy followed by surgery or surgery alone.

To be eligible for STRASS 2, patients must have high-risk leiomyosarcoma or dedifferentiated liposarcoma, the two most common subtypes of RPS. The cancer must be able to be removed by surgery.

STRASS 2 is led in the U.S. by Kenneth Cardona, MD of Emory University and the Winship Cancer Institute.

Learn more about EA7211/STRASS 2 at ecog-acrin.org.