(P 486) PRIMARY HIGH-GRADE SARCOMA OF THE SPINE: EXPERIENCE WITH 11 CASES

Objective: Spinal sarcoma presents a challenge for treatment. Although resection and reconstruction have been effective in the treatment of primary spinal sarcomas, there are limitations to resection and reconstruction of mobile spines other than the sacral spine, such as preservation of the spinal cord and cauda equina. Therefore, a consistent treatment plan is often impossible. Furthermore, because primary spinal sarcomas are extremely rare, limited reports are available on their treatment outcomes. In this study, we report our experience with 11 cases of primary spinal sarcomas and compare the clinical outcomes of the resected and reconstructed patients (R group) with those of the unresected patients (N group).

Methods: In total, 11 patients with primary spine sarcoma treated during the 10-year period from 2010 to 2020 were assessed. The R group consisted of 6 patients (three male and three female) while the N group had 5 (two male and three female). The mean age was 51.8 (15–71) years in the R group and 65.6 (36–91) years in the N group. Group R consisted of two cases of Ewing’s sarcoma (Th6, S2), two cases of leiomyosarcoma (L4, L4), one case of chondrosarcoma (C6), and one case of undifferentiated pleomorphic sarcoma (Th10). Whereas Group N consisted of two cases of osteosarcoma (Th9, Th11/12), one case of rhabdomyosarcoma (L5), one case of clear cell sarcoma of soft tissue (L5), and one case of undifferentiated pleomorphic sarcoma (L4). We analysed and compared the treatment outcomes, survival, and Activities of Daily Living (ADL) between the two groups. The overall survival (OS) was estimated using Kaplan–Meier plots and the prognostic significance was evaluated using the log-rank test.

Results: The mean tumour diameter at the first visit was 48.3 (24–68) mm in the R group and 47.6 (38–75) mm in the N group. The Weinstein classification was IIA in one case and IIB in five cases in Group R, and IIA in two cases and IIB in three cases in Group N. Of the six patients in Group R, four received chemotherapy, two received radiation therapy, and one received carbon ion radiotherapy. Of the five patients in Group N, three received chemotherapy, two received radiation therapy, and one received proton therapy. Metastases to other organs were observed in 7 patients (63.6%). Recurrence was observed in 2 (33%) patients in the R group. Comparing between the two groups, metastases to other organs were observed in three patients in Group R (50%) and four in Group N (80%). In Group R, two patients (33%) were continuously disease free, one (17%) was alive with disease, two (33%) died of disease (DOD), and one died (17%) of death due to other causes (DOC); while in Group N, all patients were dead, including four (80%) cases of DOD and one (20%) case of DOC. The 5-year OS rates were 60% for Group R and 0 % for Group N and the 5-year OS in Group R was associated with significantly improved survival (p=0.0055). Regarding postoperative ADLs, five patients (83%) in Group R and one patient (20%) in Group N were ambulatory.

Conclusion: Despite the differences in patient background and sarcoma status, Group R had a relatively better remission rate, survival, and postoperative ADL than Group N. The results suggest that resection and reconstruction should be the first choice of treatment for primary spinal sarcoma, if indicated, in terms of remission rate, survival, and postoperative ADL. However, the degree of tumour invasion and the patient’s general condition must be considered.