Researchers Identify Trends in Treatment for Retroperitoneal Soft-Tissue Sarcoma

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Researchers have published an analysis of strategies for treating retroperitoneal soft-tissue sarcoma, which has historically been understudied due to its rarity. The researchers say the trends they identified—particularly the convergence of certain treatments across centers—will help guide the way for future research and, ultimately, standardization of care that will lead to better patient outcomes. Their findings were published by Villano et al in the Annals of Surgical Oncology.

“Heterogeneity of treatment over time has begun to close between different types of hospitals, which is a good thing,” said first study author Anthony M. Villano, MD, a second-year fellow in Fox Chase Cancer Center’s Department of Surgical Oncology. “I think the more evidence-based [in our treatment approach] we can become, the more we can standardize treatment for these patients across different types of centers, which is important. We want to ensure that patients get the best care they can no matter what center they go to.”

Retroperitoneal soft-tissue sarcoma forms behind the peritoneum lining the abdominal wall. It is challenging to manage because most retroperitoneal soft-tissue sarcoma tumors aren’t discovered until they grow large enough to impinge on other organs like the kidneys or stomach. Moreover, there is a paucity of research because retroperitoneal soft-tissue sarcoma is so rare, representing less than 1% of all human malignancies diagnosed each year in the United States. As a result, most retroperitoneal soft-tissue sarcoma treatment is based on expert opinion as opposed to randomized clinical trials.

National Cancer Database Sample

In light of the success of a recent multinational, multi-institutional retroperitoneal soft-tissue sarcoma study known as STRASS, Dr. Villano and his colleagues tapped into the National Cancer Database to assess the current state of treatment strategies. “The whole group felt it was a good time to reassess the question of what the treatment strategies were across the U.S. at this point in time. You really don’t know where you’re heading if you don’t know where you’ve come from,” said Dr. Villano. He added that they hoped their findings would inform which critical issues to investigate in an international trial.

Using a sample of 5,992 patients who underwent surgery for retroperitoneal soft-tissue sarcoma between 2004 and 2017, the researchers looked at three things. The first was what methods were used to treat patients with the disease; they then looked at whether the frequency of use of those treatments changed over the study period; finally, they compared treatment use according to how many patients with retroperitoneal soft-tissue sarcoma a hospital treated annually. Centers that conducted fewer than 10 surgeries for retroperitoneal soft-tissue sarcoma per year were categorized as low-volume, and those that conducted more than 10 such surgeries per year were deemed high-volume.

The data revealed three primary strategies: surgery, radiation, and chemotherapy. Although surgery was almost universally utilized, surgeons at high-volume centers were performing multivisceral resections—surgeries where an organ adjacent to the tumor is also removed to help prevent local recurrence—at higher rates than surgeons at low-volume centers. In addition, low-volume centers employed postoperative radiation more frequently than high-volume centers, despite guidelines from the National Comprehensive Cancer Network® (NCCN®) indicating a preference for preoperative rather than postoperative radiation.

“Low-volume centers are potentially salvaging incomplete resections with postoperative radiation because they may not be as aggressively resecting the tumors as surgeons at high-volume centers,” Dr. Villano said.

Nevertheless, the researchers found that the rates of postoperative radiation at low-volume centers were decreasing over the years of the study, while their rates of preoperative radiation were increasing to more closely match high-volume practices and align with NCCN Clinical Practice Guidelines in Oncology.

“Standardization over time is a good thing, I think, for patients overall,” said Dr. Villano.

Disclosure: For full disclosures of the study authors, visit

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