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Updated: Jun 6, 2026
Proton Therapy Delivery and Its Clinical Application in Select Solid Tumor Malignancies
Published on: February 6, 2019
Carbon ion radiotherapy for unresectable primary or recurrent soft tissue sarcomas: long-term outcomes based on the
Ping Li1,2,3, Yongqiang Li2,3,4, Cihang Bao1,2,3
1Department of Radiation Oncology, Shanghai Proton and Heavy Ion Center, Shanghai, China.
Background:
The application of carbon ion radiotherapy (CIRT) for unresectable primary or recurrent soft tissue sarcoma (STS) remains controversial and existing data are limited. We herein present our institutional experience with CIRT for unresectable primary or recurrent STS.
Methods:
We retrospectively evaluated the outcomes of CIRT in unresectable primary or recurrent STS patients at our center. We assessed the 4-and 5-year local control (LC), overall survival (OS), distant metastasis free survival (DMFS), progression free survival (PFS), as well as acute and late toxicities. Additionally, we analyzed the prognostic factors associated with the treatment outcomes.
Results:
Between June 2015 and August 2022, 48 consecutive patients with unresectable primary (n = 8, 16.7%) or recurrent (n = 40, 83.3%) STS were treated with CIRT. The most common tumor sites were the retroperitoneum and pelvis (75.0%). The predominant histological subtypes included liposarcoma (20.8%), leiomyosarcoma (10.4%), synovial sarcoma (8.3%) and undifferentiated pleomorphic sarcoma (8.3%). Nine patients (18.8%) had a history of prior in-field radiotherapy. The median follow-up duration was 48.6 months. The 4-year LC, OS, DMFS, and PFS rates were 65.8%, 59.7%, 50.3%, and 36.7%, respectively. The 5-year LC, OS, DMFS, and PFS rates were 60.3%, 54.7%, 44.0%, and 28.0%, respectively. The median survival time was 67.3 months. Late toxicities included grade 3 dermatitis (n = 2, 4.2%), grade 3 decreased joint range of motion (n = 1, 2.1%), and grade 3 peripheral neuropathy (n = 1, 2.1%). Patients who received a higher prescribed dose (biologically effective dose, BED ≥ 129 Gy) exhibited significantly better LC (p = 0.010) and PFS (p = 0.004) compared to those who received a lower prescribed dose. A pre-CIRT neutrophil-to-lymphocyte ratio (NLR) ≥ 3 was significantly associated with inferior DMFS (p = 0.020).
Conclusions:
For select patients with unresectable primary or recurrent STS, CIRT represents a potentially effective and well-tolerated treatment option, though it requires careful evaluation of neural risks-particularly for lesions adjacent to critical nerve structures.
