Reduction in Late Toxicities With Preoperative Image-Guided Radiation Therapy to Reduced Target Volume in Patients With Extremity Sarcoma
As reported in the Journal of Clinical Oncology by Wang et al, the incidence of late toxicity among patients with extremity soft-tissue sarcoma receiving preoperative image-guided radiotherapy to a reduced target volume in the phase II Radiation Therapy Oncology Group (RTOG) 0630 trial was lower than that observed with preoperative radiotherapy without image-guided radiotherapy in the phase III National Cancer Institute of Canada SR2 trial (CAN-NCIC-SR2). The latter trial showed a lower incidence of late toxicity with preoperative vs postoperative radiotherapy in this setting.
Low Rate of Late Toxicity
The analysis included 79 patients from RTOG 0630 who received image-guided radiotherapy without chemotherapy followed by limb-sparing resection. Late toxicities were assessed at 2 years.
At a median follow-up of 3.6 years, five patients did not undergo surgery, due to disease progression. Local treatment failure (all in-field) occurred in five patients. Among 57 patients assessed for late toxicities, 10.5% had at least one grade ≥ 2 toxicity, compared with 37% of 73 patients in the CAN-NCIC-SR2 trial (P < .001). Rates of individual toxicities were 5.3% vs 31.5% for fibrosis, 3.5% vs 17.8% for joint stiffness, and 5.3% vs 15.1% for edema. Resection of major blood vessels in 10 vs 46 patients was associated with increased late subcutaneous fibrosis in 2 vs 1, joint stiffness in 2 vs 0, and edema in 0 vs 3.
The investigators concluded: “The significant reduction of late toxicities in patients with extremity [soft-tissue sarcoma] who were treated with preoperative image-guided radiotherapy and absence of marginal-field recurrences suggest that the target volumes used in the Radiation Therapy Oncology Group RTOG-0630 (A Phase II Trial of Image-Guided Preoperative Radiotherapy for Primary Soft-Tissue Sarcomas of the Extremity) study are appropriate for preoperative image-guided radiotherapy for extremity [soft-tissue sarcoma].”
Dian Wang, MD, of Rush University Medical Center, is the corresponding author for the Journal of Clinical Oncology article.
The study was supported by grants from the National Cancer Institute. For full disclosures of the study authors, visit jco.ascopubs.org.
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