Clinical Outcomes and Prognostic Factors in Patients With Pelvic Sarcomas

Background/Aim: Pelvic sarcomas are rare malignant tumors arising from the bone or soft tissue and are associated with poor clinical outcomes. Their deep anatomical location and large tumor size often limit complete surgical resection, and optimal treatment strategies remain controversial. Carbon-ion radiotherapy (CIRT) has emerged as an advanced radiotherapeutic option; however, its clinical significance in pelvic sarcomas remains unclear. This study aimed to investigate clinical outcomes and prognostic factors in patients with pelvic sarcomas.

Patients and Methods: We retrospectively reviewed 20 patients with pelvic sarcomas treated at a single institution between 2015 and 2025. Clinical characteristics, treatment modalities, and outcomes were analyzed. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan–Meier method, and univariate analyses were performed to evaluate associations between clinical variables and survival outcomes.

Results: The median age at diagnosis was 70.5 years, and the median tumor size was 94.5 mm. Surgical resection was performed in two patients, while chemotherapy and radiotherapy were each administered in 60% of the patients. Among patients receiving radiotherapy, seven underwent CIRT. The median OS and PFS were 33 and 32 months, respectively. Larger tumor size (≥95 mm) was significantly associated with poorer overall survival [odds ratio (OR)=21.3, p=0.006], whereas treatment with CIRT was significantly associated with improved overall survival (OR=0.05, p=0.007). Two patients died from non–cancer-related causes following severe postoperative complications after surgery.

Conclusion: In this retrospective exploratory analysis, tumor size and the use of carbon-ion radiotherapy were associated with survival in patients with pelvic sarcomas. Large tumor size was linked to unfavorable outcomes, whereas CIRT was associated with improved survival. Although limited by the small sample size and potential selection bias, these findings suggest that CIRT may represent a potential treatment option for selected patients with pelvic sarcomas and highlight the importance of individualized treatment strategies.