PHILADELPHIA (March 16, 2022)—Researchers from Fox Chase Cancer Center have published an analysis of strategies for treating retroperitoneal soft tissue sarcoma (RPS), a form of cancer that 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.
“Heterogeneity of treatment over time has begun to close between different types of hospitals, which is a good thing,” said Anthony M. Villano, MD, a second-year fellow in Fox Chase’s Department of Surgical Oncology and first author on the paper.
“I think the more evidence-based 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.”
RPS is a soft-tissue cancer that forms behind the peritoneum, which is the tissue lining the abdominal wall. It is challenging to manage because most RPS 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 RPS is so rare, representing less than 1% of all human malignancies diagnosed each year in the United States. As a result, most RPS treatment is based on expert opinion as opposed to randomized clinical trials.
In light of the success of a recent multinational, multi-institutional RPS study known as STRASS, Villano and Fox Chase colleagues, including Margaret von Mehren, MD, vice chair of the Department of Hematology/Oncology and chief of the Division of Sarcoma Medical Oncology, and Jeffrey M. Farma, MD, FACS, chief of the Division of General Surgery, tapped into the National Cancer Database to assess the current state of RPS 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 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 RPS between 2004 and 2017, the researchers looked at three things. The first was what methods were used to treat patients with RPS. 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 RPS patients a hospital treated annually.
Centers that conducted fewer than 10 RPS surgeries per year were categorized as “low volume” (LV), and those that conducted more than 10 RPS surgeries per year were deemed “high volume” (HV).
The data revealed three primary strategies for treating RPS: surgery, radiation, and chemotherapy. Although surgery was almost universally utilized, surgeons at HV 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 LV centers.
In addition, LV centers employed postoperative radiation more frequently than HV 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 postop radiation because they may not be as aggressively resecting the tumors as surgeons at high-volume centers,” Villano said.
Nevertheless, the researchers found that the rates of postoperative radiation at LV centers were decreasing over the years of the study, while their rates of preoperative radiation were increasing to more closely match HV practices and align with NCCN Clinical Practice Guidelines in Oncology.
“Standardization over time is a good thing, I think, for patients overall,” said Villano.
The study, “National Trends in Treatment for Retroperitoneal Soft Tissue Sarcoma: A Modern Appraisal of Variability in Therapeutic Strategies,” was published in Annals of Surgical Oncology.