Effect of Cisplatin Arterial Infusion (CAI) on Primary Nonmetastatic Pelvic Osteosarcoma: A Preliminary Study

Background: The critical role of arterial infusion chemotherapy in the multimodal treatment of extremity bone cancer has been investigated extensively, but few studies have focused on pelvic osteosarcoma. Therefore, we attempted to evaluate the clinical significance of arterial infusion chemotherapy in the treatment of pelvic osteosarcoma.Methods: We combined a cisplatin arterial infusion regimen with multidrug systematic chemotherapy as a neoadjuvant protocol for the treatment of pelvic osteosarcoma. The course number and dosage of cisplatin arterial infusion were adjusted to achieve a maximal tumor response evaluated by contrast-enhanced MRI per RECIST 1.1. Good responders received the same systematic combination for postoperative chemotherapy, and poor responders received second-line therapy. Twelve patients with nonmetastatic high-grade pelvic osteosarcoma were included. Survival, chemotherapy response and adverse events data were analyzed. Results: The mean follow-up period was 56.1 months. Four patients died of refractory tumor progression, and 1 patient with local recurrence had no evidence of disease for 27 months after receiving secondary amputation and resection. Kaplan-Meier survival analysis demonstrated a 57.8% overall survival and 52.5% event-free survival rate at 5 years. Eight of 12 patients had a >90% tumor necrosis rate according to histopathologic examinations. The rates of local adverse events were lower than those reported for extremity osteosarcoma. Conclusions: Our study initially indicated that the cisplatin arterial infusion regimen was a potential therapy with good tolerance in the treatment of pelvic osteosarcoma.

Outcomes of extra-skeletal versus skeletal Ewing sarcoma patients treated with standard chemotherapy protocol.

11027 Background: Extra-skeletal ewing sarcomas (ES) are rare, and data on outcomes following standard ES chemotherapy protocols are very limited. Methods: We retrospectively collected data on skeletal and extra-skeletal ES patients who presented with localized disease from January, 2006 to June, 2018. Disease and treatment characteristics were compared between the two groups by the chi-square test. Overall survival (OS) and local recurrence free survival (LRFS) were estimated by the Kaplan-Meier method and compared by the Log-rank test. Results: A total of 120 patients were included. Twenty-nine (24%) had extra-skeletal and 91 (76%) had skeletal ES. Location was in the extremity in 51 (43%) and non-extremity in 69 (57%). For extra-skeletal ES, tumors originated from soft tissue in 23 (79%), and viscera in 6 (21%). All patients received standard vincristine, doxorubicin, and cyclophosphamide alternating with ifosfamide and etoposide (VDC-IE), with a plan for local control at week 12 of the protocol. Local control was by surgery in 76 (63%) and radiotherapy in 44 (37%). At a median follow up of 38 months, there was no difference in 5-year OS between extra-skeletal and skeletal ES patients (67% and 70% respectively, p = 0.96). Patients with visceral ES had inferior 5-year OS compared to all others (soft-tissue extra-skeletal and skeletal ES); 33% vs. 72%; p = 0.013. Resectability rate was not different between extra-skeletal and skeletal ES patients (54% and 69% respectively, p= 0.11). Furthermore, among patients who underwent surgery, there was no difference between extra-skeletal and skeletal ES patients in R0 resection rate (86% and 89% respectively, p= 0.52) and poor ( < 90%) tumor necrosis rate (62% and 46% respectively, p= 0.31). However, more local recurrences (28% vs. 10%, p= 0.034) and inferior 5-year LRFS (74% vs. 83%; p = 0.042) were observed in the extra-skeletal group, although more extra-skeletal patients received adjuvant radiotherapy; 11 (73%) vs. 21 (36%), p = 0.01. Conclusions: Patients with localized extra-skeletal ES have OS outcomes that are comparable to skeletal ES treated with standard VDC-IE chemotherapy. However, extra-skeletal ES patients are at significantly higher risk of local recurrence.