Body wall primary tumors in non-rhabdomyosarcoma soft tissue sarcoma

We used data from ARST0332, a risk-based treatment for non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) in pediatric patients from Children’s Oncology Group to study the difference between patients with body wall primary tumors and patients with non-body wall primary tumors. There are 529 evaluable patients with NRSTS in the study, 75 having a primary tumor site at body wall. Results from Fisher’s exact test indicated patients with body wall tumors had statistically significantly different features, including tumor size (p=0.0383) and tumor depth (p=0.0314), than patients with non-body wall tumor. The survival probability of event-free survival and overall survival were not significantly different between body wall and non-body wall patients (EFS p-value=0.1243, OS p-value=0.9922). Using Cox proportional hazards regression, we found risk group (low, intermediate, high) to be a strong predictor of overall survival, where high risk had hazard ratio of 1.981 (95% CI: 0.603, 6.511) vs. intermediate risk and low risk had hazard ratio of 0.180 (95% CI: 0.039, 0.835) vs. intermediate risk. Treatment arm (the therapy patients received) was also a strong predictor in the event-free survival model, as determined by an interaction term between risk group and treatment arm.