A. J. Arifin, A. J. Bishop, D. Mitra, D. Araujo, E. F. Nassif Haddad, R. Ratan, J. A. Livingston, V. Lewis, P. Lin, B. Moon, E. Keung, C. L. Roland, C. Scally, B. A. Guadagnolo, and A. Farooqi; The University of Texas MD Anderson Cancer Center, Houston, TX
Purpose/Objective(s): The role of radiation therapy (RT) for metastatic soft tissue sarcoma (STS) is evolving, with evidence that selective metastasis-directed local therapy may be beneficial. However, there is a paucity of data regarding optimal treatment of the primary site for metastatic STS. RT or surgery alone can be used to control disease with studies demonstrating local control rates of 50–70%. However, for STS patients with longer life expectancy despite metastatic disease, we hypothesize that combined modality local therapy (CMT) will be beneficial for local control without excess toxicity. Materials/
Methods: We identified 19 patients with metastatic STS who underwent moderately hypofractionated preoperative RT and surgery to the primary in both de novo and recurrent settings. All patients were discussed at tumor board and selectively identified to potentially benefit from a CMT approach. All patients received 40.05 Gy in 15 daily fractions. Results: The median age was 65 (IQR: 50–71). The most common primary sites of disease were in the lower extremities (n=12, 63%) and upper extremities (n=4, 21%). The most common histology was undifferentiated pleomorphic sarcoma (n=5, 26%) and most lesions were high-grade (n=12, 63%). Median size was 7.6 cm (IQR: 4.4–12.7 cm). 10 patients (53%) had a new diagnosis of sarcoma, while 9 (47%) had locally recurrent disease. After multidisciplinary discussion, the rationale(s) for CMT included: oligometastatic disease (=5 sites; n=13, 68%), favorable systemic therapy response (n=5, 26%), worrisome location or symptoms (n=4, 21%) and increased risk of local recurrence (e.g., multifocal; n=1, 5%). 14 patients (74%) received systemic therapy immediately before (n=10) or after (n=4) primary site treatment. 7 patients (37%) underwent additional metastasis-directed local therapy around the time of the primary tumor management. Pain reduction was documented in 89% of patients who presented with pain (8 of 9) after CMT. 1 patient (5%) had an in-field local recurrence. With a median follow-up of 21 months, 2-year local recurrence-free survival, progression-free survival and cancer-specific survival rates were 92%, 36% and 65%. The rate of wound complications within 120 days of surgery was 16%. The rate of late RT toxicities was 26%, including grade 1 (n=2), and grade 2 (n=3) lymphedema; there were no grade =3 late toxicities. Conclusion: For properly selected metastatic STS patients with good performance status and long expected survival, a CMT approach offers favorable local control, low toxicity, and pain mitigation in those with painful primary tumors. In these patients, combined modality primary treatment should be considered as it provides better local control compared to an RT-alone approach.
