CHICAGO — A risk-based treatment strategy categorized pediatric patients with nonrhabdomyosarcoma soft tissue sarcomas into distinct prognostic groups while utilizing less radiotherapy at lower doses, according to findings from the Children’s Oncology Group study ARST0332 presented at the ASCO Annual Meeting.
“Nonrhabdomyosarcoma soft tissue sarcomas comprise about 4% of childhood cancer, but they have been very poorly studied during the past 4 decades with only three prospective clinical trials being conducted in North America,” Sheri L. Spunt, MD, MBA, professor of pediatrics in hematology and oncology at the Lucile Salter Packard Children’s Hospital, said during a presentation. “As a result, there is no clear standard of care for most of these patients. However, retrospective studies have suggested that outcome is predicted by tumor grade, size, the extent of surgical resection and the extent of disease — similar to adults with soft tissue sarcoma.”
Spunt and colleagues sought to evaluate outcomes in 551 patients with a median age of 13.7 years with newly diagnosed nonrhabdomyosarcoma soft tissue sarcomas.
Patients were assigned to one of four risk-based treatment categories. Arm A included patients who underwent surgery with grossly excised low-grade tumors or a ≤ 5 cm widely excised high-grade tumor; arm B included those with a ≤ 5 cm marginally resected high-grade tumor; arm C included those with a > 5 cm grossly resected tumor ± metastases; and arm D included those with a > 5cm unresected tumor ± metastases.
Synovial sarcoma (n=149), malignant peripheral nerve sheath tumor (n=60) and undifferentiated sarcoma (n=48) were the most common tumor subtypes.
Fifty-three percent of patients had extremity tumors; 72% were of high grade; 76% were larger than 5 cm and 14% had metastatic disease that was predominantly located in the lung.
The estimated 4-year event-free survival was 91% for arm A; 73% for arm B; 64% for arm C; and 49% for arm D. Overall survival was 97% for arm A, 100% for arm B, 80% for arm C and 63% for arm D. No toxic deaths occurred.
“There are a number of future analyses planned for this study, including prognostic factor analyses looking at clinical and biological factors,” Spunt said. “The overall outcomes were similar to other retrospective studies, despite the use of lower radiation. However, I want to caution that the toxicity of the therapy used in this study is not negligible, and we need to be careful in assuming that the therapy provided is the standard of care. Further research is needed to identify more effective and less toxic therapies for patients with these tumor types.”
For more information:
Spunt SL. Abstract #10008. Presented at: ASCO Annual Meeting; May 30-June 3, 2014; Chicago.
Disclosure: The researchers report no relevant financial disclosures.