Natural History of Kids’ Benign Bone Tumors; Sarcoma Staging; Pathologic Fractures

Almost 20% of asymptomatic children and adolescents had benign bone tumors of the extremities, a review of a longitudinal radiographic collection showed.

Overall, 35 benign tumors were identified in 33 pediatric patients whose median age was 8. The most commonly identified tumor types were non-ossifying fibromas (NOF, 7.5%), enostoses (5.2%), osteochondromas (4.5%), and enchondromas (1.8%).

The findings came from a review of the Brush Inquiry, a collection of 25,555 radiographs and 262 healthy children. The x-rays were all left-sided views of each patient’s upper and lower extremities. The overall incidence of benign tumors in the asymptomatic population was 18.9%, and the median age at detection after a previous negative radiograph was 9 years. NOFs were the only tumor type that resolved over time, Christopher D. Collier, MD, of the University of Chicago, reported during the Musculoskeletal Tumor Society (MSTS) virtual meeting.

“The goal of this study was to give us more accurate information on the overall incidence of these [tumors] and the natural history,” MSTS program co-chair Thomas J. Scharschmidt, MD, of Ohio State University in Columbus, said during a review of selected abstracts. “The impetus for the study is that those of us in the oncology world have a lot of consults for NOFs, osteochondromas, and other things that can cause a lot of anxiety for families. This information provides us with some numbers to be able to counsel families when they are sent to us.”

Following are summaries of two other abstracts from the meeting.

Skeletal Staging in Bone Sarcomas

As many as 35% of patients with bone sarcomas and bony metastases at diagnosis would have gone undetected if staging had included only a CT scan of the lungs, a separate review of 9,855 patients showed.

The analysis of the National Cancer Database included patients with newly diagnosed bone sarcomas during 2010-2015: 4,013 patients with chondrosarcoma, 4,105 with osteosarcoma, and 1,737 with Ewing sarcoma. The data showed that 11.7% of patients had lung metastases and 4.8% had bone metastases at diagnosis. The presence of bone metastases was associated with worse survival in each of the three histologies and in all histologies combined (P<0.01).

The study had its origin in the growing interest in modified staging protocols that challenge the value of skeletal staging, Collier and colleagues noted in a poster presentation. The data showed that lung-only staging would have missed metastatic disease in 16% of patients with osteosarcoma, 25% of those with chondrosarcoma, and 35% of patients with Ewing sarcoma.

“I think we probably routinely get bone staging, more so in our bone sarcomas and soft-tissue sarcomas, but I think this study really highlighted the importance of that as well as the poor outcomes with bone metastases overall across all of these bone sarcomas,” said Scharschmidt.

Pathologic Fracture and Limb Salvage Outcomes

Pathologic fracture did not adversely affect patient or implant survival following limb salvage surgery for osteosarcoma, a review of 304 cases showed.

During a median follow-up of 13 years, 17 (5.6%) patients had a pathologic fracture at initial assessment or during preoperative chemotherapy. Five (29.4%) with pathologic fracture died of cancer versus 89 (31%) of those without fracture. Three patients with pathologic fracture suffered implant failure, for a rate of 17%, versus 32.8% in the patients without fracture. Fracture was not associated with an increased incidence of distant metastasis (35.2% vs 38.3%).

The risk of locoregional recurrence was numerically higher in patients who had pathologic fractures (17.6% vs 9.4%, P=0.27), but larger studies are needed to determine the significance of the finding, reported Danielle Greig, MD, of the University of California Los Angeles, and colleagues.

“Limb salvage surgery can be performed in patients with pathologic fracture with excellent long-term survival,” they added.

Last Updated October 12, 2020