Sarcoma and Cutaneous Tumors

PV QA 2 - Poster Viewing Q&A 2

MO_21_2482 - Pre- vs post-operative radiation therapy, and time to surgery: An exploratory analysis of predictors of survival in soft tissue sarcoma stratified by histological subtype

Monday, October 22
10:45 AM - 12:15 PM
Location: Innovation Hub, Exhibit Hall 3

Pre- vs post-operative radiation therapy, and time to surgery: An exploratory analysis of predictors of survival in soft tissue sarcoma stratified by histological subtype
Z. S. Buchwald1, C. Fortune1, C. Zhang2, M. Abugideiri1, J. Jhaveri1, R. H. Press1, T. Morgan1, S. Tian3, M. Yushak4, K. D. Godette1, J. C. Landry3, K. Cardona5, and M. K. Khan1; 1Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, 2Department of Biostatistics and Bioinformatics Shared Resource, Winship Cancer Institute of Emory University, Atlanta, GA, 3Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, 4Department of Hematology and Medical Oncology, WInship Cancer Institute of Emory University, Atlanta, GA, 5Department of Surgery, Winship Cancer Institute of Emory University, Atlanta, GA

Purpose/Objective(s): Soft tissue sarcoma (STS) is a heterogeneous disease composed of many histological subtypes that is treated largely with the same paradigm. Surgery is the primary treatment for localized STS. Peri-operative radiation (RT) and chemotherapy are adjunctive treatments; their use can be tailored by the presence of nodal and/or distant metastases. For patients receiving pre-operative RT, we aimed to determine the impact of time from RT to surgery on survival. Survival and disease outcomes were also evaluated, stratified by histologic subtype, timing of peri-operative RT, and the presence of genetic alterations.

Materials/Methods: We retrospectively reviewed STS patients from 2000-2015 undergoing multimodality management including surgery and RT at a single institution. They were stratified by time from RT to surgery (defined as the end of radiotherapy to the date of resection), receipt of pre- vs post-operative RT by histologic subtype, survival by histologic subtype and genetic aberrations. Actuarial overall survival (OS) and freedom from distant metastases (FDM) were assessed by the Kaplan-Meier method and subgroups compared by log-rank tests.

Results: 302 patients with localized STS were treated with surgery and either pre-operative (n=213) or post-operative (n=89) RT. 78 patients received chemotherapy, given either neoadjuvantly, adjuvantly, or both. On multivariable analysis (MVA), a longer interval from RT to surgery was associated with inferior OS (HR: 1.10 (95% CI 1.02-1.18), p=0.012) in patients who received pre-operative RT. Receiving post-operative RT vs pre-operative RT was associated with a trend towards improved FDM (90% vs 63.6%, p=0.087) and OS (100% vs 72.4%, p=0.078) in leiomyosarcoma patients. This effect of radiation sequencing was not seen in any other histologic subtype (p>0.05). 3-year FDM and OS rates by histologic subtype were: 67.3% and 77.3% for malignant histiocytoma/ pleomorphic sarcomas (n=115), 77.4% and 78.3% for liposarcoma (n=58), 71.5% and 81.8% for leiomyosarcomas (n=37), 75.7% and 85.4% for synovial sarcomas (n=31), 76.3% and 68.8% for fibrosarcomas (n=19), 67.5% and 87.5% for peripheral nerve sheath tumors (n=10). Genetic alternations, specifically DDIT3-gene fusions (n=2), MDM2 amplifications (n=8) or SYT translocations (n=11), did not affect DFM or OS in the univariate setting (p=0.84).

Conclusion: A longer interval between the end of radiation therapy and surgery is an independent predictor of worse overall survival. Post-operative RT may be associated with favorable FDM and OS in leiomyosarcoma compared to pre-operative RT. These findings may help refine treatment decision-making in a highly heterogeneous disease.

Author Disclosure: Z.S. Buchwald: None. C. Fortune: None. C. Zhang: None. T. Morgan: None. S. Tian: None. K.D. Godette: None. J.C. Landry: None.

Send Email for Zachary Buchwald


Assets

MO_21_2482 - Pre- vs post-operative radiation therapy, and time to surgery: An exploratory analysis of predictors of survival in soft tissue sarcoma stratified by histological subtype



Attendees who have favorited this

Please enter your access key

The asset you are trying to access is locked. Please enter your access key to unlock.

Send Email for Pre- vs post-operative radiation therapy, and time to surgery: An exploratory analysis of predictors of survival in soft tissue sarcoma stratified by histological subtype