Abstract | PURPOSE: METHODS AND MATERIALS: We reviewed the records of 596 patients with STS of the proximal lower extremity consecutively treated with surgery and radiation therapy (RT) from 1966 to 2012. One hundred ninety-seven patients (33%) received 50 Gy to the entire femur circumference (n = 197, 33%); 265 patients (45%) received perioperative chemotherapy, and during surgery, 155 patients (26%) had bone exposure, whereas 82 patients (14%) had the periosteum stripped. The Kaplan-Meier method was used to estimate actuarial outcome rates, and both Cox regression modeling and competing risk analyses using the method of Fine and Gray were performed. RESULTS: Median follow-up time was 110 months (range, 6-470 months). The actuarial 10-year local control and overall survival rates were 88% (95% confidence interval [CI], 84%-90%) and 62% (95% CI, 57%-66%). Twelve patients had pathologic fractures, which were associated with 50 Gy to the entire bone circumference (P < .001), bone exposure (P < .001), and periosteal stripping during surgery (P < .001) and use of perioperative chemotherapy (P = .04). Using a competing risk model, bone exposure (P = .001; sub-hazard ratio [SHR], 9.13; 95% CI, 2.5-33.0), periosteal stripping (P < .001; SHR, 13.03; 95% CI, 4.0-43.0), and perioperative chemotherapy (P = .03; SHR, 4.03; 95% CI, 1.1-14.4) were significantly associated with fracture. The actuarial 10-year fracture rate was 2% (95% CI, 1%-3%) when the 50-Gy isodose line encompassed the entire bone circumference without the other risk factors, whereas it increased to 37% (95% CI, 12%-45%) when all 4 treatment-related factors were present. CONCLUSIONS: Although femur fractures are rare, a component from each of the 3 therapeutic modalities contributes to the overall risk, and a multidisciplinary approach to mitigating fracture risk is needed. Although avoiding circumferential bone coverage with the 50-Gy isodose line may be a valuable dosimetric parameter, more rigorous dosimetric studies are required.
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Authors | Andrew J Bishop, Gunar K Zagars, Pamela K Allen, Bryan S Moon, Patrick P Lin, Valerae O Lewis, B Ashleigh Guadagnolo |
Journal | Practical radiation oncology
(Pract Radiat Oncol)
2016 May-Jun
Vol. 6
Issue 3
Pg. 194-200
ISSN: 1879-8519 [Electronic] United States |
PMID | 27126136
(Publication Type: Journal Article)
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Copyright | Copyright © 2016 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved. |
Topics |
- Adult
- Combined Modality Therapy
- Female
- Femoral Fractures
(etiology, pathology)
- Humans
- Lower Extremity
(pathology)
- Male
- Middle Aged
- Risk Factors
- Sarcoma
(complications, pathology)
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