Radiat Oncol J.  2019 Jun;37(2):117-126. 10.3857/roj.2018.00549.

Characterization and predictive value of volume changes of extremity and pelvis soft tissue sarcomas during radiation therapy prior to definitive wide excision

• Gui C
• Morris CD
• Meyer CF
• Levin AS
• Frassica D
• Deville C
• Terezakis

• KMID: 2452572
• DOI: http://doi.org/10.3857/roj.2018.00549

Abstract

PURPOSE
The purpose of this study was to characterize and evaluate the clinical significance of volume changes of soft tissue sarcomas during radiation therapy (RT), prior to definitive surgical resection.
MATERIALS AND METHODS
Patients with extremity or pelvis soft tissue sarcomas treated at our institution from 2013 to 2016 with RT prior to resection were identified retrospectively. Tumor volumes were measured using cone-beam computed tomography obtained daily during RT. Linear regression evaluated the linearity of volume changes. Kruskal-Wallis tests, Mann-Whitney U tests, and linear regression evaluated predictors of volume change. Logistic and Cox regression evaluated volume change as a predictor of resection margin status, histologic treatment response, and tumor recurrence.
RESULTS
Thirty-three patients were evaluated. Twenty-nine tumors were high grade. Prior to RT, median tumor volume was 189 mL (range, 7.2 to 4,885 mL). Sixteen tumors demonstrated significant linear volume changes during RT. Of these, 5 tumors increased and 11 decreased in volume. Myxoid liposarcoma (n = 5, 15%) predicted decreasing tumor volume (p = 0.0002). Sequential chemoradiation (n = 4, 12%) predicted increasing tumor volume (p = 0.008) and corresponded to longer times from diagnosis to RT (p = 0.01). Resection margins were positive in three cases. Five patients experienced local recurrence, and 7 experienced distant recurrence, at median 8.9 and 6.9 months post-resection, respectively. Volume changes did not predict resection margin status, local recurrence, or distant recurrence.
CONCLUSION
Volume changes of pelvis and extremity soft tissue sarcomas followed linear trends during RT. Volume changes reflected histologic subtype and treatment characteristics but did not predict margin status or recurrence after resection.

Keyword

Soft tissue sarcoma; Radiographic progression; Response to radiation; Tumor control

MeSH Terms

Cone-Beam Computed Tomography
Diagnosis
Extremities*
Humans
Linear Models
Liposarcoma, Myxoid
Pelvis*
Recurrence
Retrospective Studies
Sarcoma*
Tumor Burden