2118 - Outcomes for Patients with Localized Intrathoracic Soft Tissue Sarcomas Treated with Surgery and Radiation Therapy
Presenter(s)
T. S. Kanala1, A. K. Yoder1, D. Mitra1, A. J. Bishop1, Z. Hooda2, D. Araujo3, R. Ratan3, N. Somaiah3, E. F. Nassif Haddad3, K. G. Mitchell2, R. Rajaram2, A. A. Vaporciyan2, D. C. Rice2, B. A. Guadagnolo1, and A. Farooqi1; 1Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, 2Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX, 3Department of Sarcoma Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
Purpose/Objective(s): Intrathoracic soft tissue sarcomas (STS) are rare malignancies for which there is a paucity of data to formulate optimal treatment algorithms. However, given the difficulty of achieving wide negative margin due to proximity of critical organs, radiation therapy (RT) is sometimes recommended, extrapolating based on benefits observed in other anatomic sites. We sought to investigate outcomes among patients presenting with primary non-metastatic intrathoracic STS treated using both surgery and RT.
Materials/Methods: We performed a single-institution retrospective cohort study of non-metastatic intrathoracic STS treated with curative intent surgery and RT between 1980 and 2022. STS arising in the chest wall were excluded. The Kaplan-Meier method was used to estimate disease-specific survival (DSS), distant metastasis-free survival (DMFS) and local control (LC), and univariate analyses were performed using the Log rank test.
Results: 28 patients were identified and had a median follow-up of 25 months (IQR 17.2 - 68.5). The most common histologies were synovial sarcoma (n=9, 32%), high grade sarcoma not otherwise specified (NOS) (n=6, 21%) and undifferentiated pleomorphic sarcoma (n=4, 14%). 20 (74%) had intermediate-high grade tumors. Twenty-two (79%) tumors were in mediastinum, 4(14%) had pleural origin and the rest (7%) were originating from within the lung parenchyma. Median tumor size at diagnosis was 7.5 cm (IQR 4.3-11.4). Post-operative RT (n= 20, 71%) was more common than preoperative RT (n=8, 29%). Median preoperative RT dose was 50 Gy (IQR 50.0 – 50.3) and median postoperative RT dose was 60Gy (IQR 59.9 - 63). Chemotherapy was given to 18 patients (64%). Sixteen (61%) patients had microscopic positive margin resections or uncertain margin status after surgery, and 12(39%) had negative margins. Two-year LC, DMFS, and DSS for the entire cohort was 61%, 61% and 72% respectively. The median time to local recurrence was 8 months (IQR 4.5-24.5) (n=13). Median local relapse-free survival in the cohort was 20 months (IQR 8.3 - 30) and did not differ significantly with timing of RT, margin status, size (£5cm vs >5cm), or grade (high-int vs low) of the tumor. Three patients (11%) experienced a grade 3+ toxicity after surgery and RT. Two patients developed esophageal perforation following adjuvant radiation; 1 had pericardial effusion requiring hospital admission and 1 patient with both. All 3 patients received RT at doses greater than 60Gy.
Conclusion: Among this cohort of localized intrathoracic STS treated with surgery and RT, we observed poorer local control and disease specific survival rates than what has been reported with extremity and superficial trunk STS treated using a similar approach. In these tumors, upfront multidisciplinary discussions are crucial for optimizing management, and careful considerations of the timing of RT are needed when weighing the surgical and radiation-related risks.