BONE DENSITY CHANGES AFTER RADIATION FOR EXTREMITY SARCOMAS: EXPLORING THE ETIOLOGY OF PATHOLOGIC FRACTURES
BONE DENSITY CHANGES AFTER RADIATION FOR EXTREMITY SARCOMAS: EXPLORING THE ETIOLOGY OF PATHOLOGIC FRACTURES
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DOI：
10.1016/j.ijrobp.2010.04.012
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发表时间：
2011-07-15
影响因子：
7
通讯作者：
Constine, Louis S.
中科院分区：
文献类型：
--
作者：
Dhakal, Sughosh;Chen, Jeffrey;Constine, Louis S.
目的：四肢软组织肉瘤治疗中发生的邻近骨的附带照射(RT)通常被认为是通过降低骨的密度来“削弱”骨，从而增加病理性骨折的风险。本研究旨在评估肿瘤和治疗引起的肢体功能损害后放疗和减轻机械负荷对骨密度的相对影响。方法与材料：19例四肢软组织肉瘤患者接受手术切除和放疗后，用双能X线骨密度仪测量了照射侧(A)和对侧(B)以及健侧(C)和对侧(D)四个部位的骨密度。分析包括(1)[A-B]，(2)[C-D]，(3)[(A-B)，-(C-D)]和(4)[(A-B)/B-(C-D)/D]。结果：经负重校正后，所有照射部位的平均骨密度较对照侧增加0.08+/-0.22g/cm(2)(方差)。当将不同解剖部位的骨密度差值除以个体对照密度而归一化时，骨密度平均增加9+/-22%(p=0.08)。结论：在校正负重或机械效应后，RT不会常规地降低骨密度。已知的照射骨病理性骨折风险增加的发病机制可能是多因素的，包括可能的骨重建改变，从而导致稳定的甚至增加的骨密度。需要进一步的临床和基础研究来证实我们意想不到的发现。(C)2011年爱思唯尔公司。
Purpose: The incidental irradiation (RT) of adjacent bone that takes place during treatment of soft tissue extremity sarcomas is generally presumed to "weaken" the bone by decreasing its density, which subsequently increases the risk for pathologic fracture. This investigation intended to assess the relative effects on bone density of both RT and diminished mechanical loading secondary to tumor-induced and therapy-induced functional extremity impairment.Methods and Materials: 19 patients treated with surgical excision and RT for soft tissue extremity sarcomas had bone density measured using dual energy X-ray absorptiometry at four sites: the irradiated (A) and contralateral (B) bone, and an uninvolved bone (C) in the treated extremity and its contralateral counterpart (D). Analysis included (1) [A-B], (2) [C-D], (3) [(A-B), - (C-D)], and (4) [(A-B)/B - (C-D)/D].Results: The mean bone density for all irradiated sites was increased 0.08 +/- 0.22 g/cm(2) (variance) compared to the contralateral unirradiated side when corrected for weight-bearing effects (3). An average increase in bone density of 9 +/- 22% (p = 0.08) was also seen when the differences were divided by individual control densities to normalize variation in density of different anatomic sites (4).Conclusions: RT does not routinely decrease bone density when corrected for weight bearing or mechanical effects. The pathogenesis for the known increased risk of pathologic fracture in irradiated bones is likely multifactorial, including possible alterations in bone remodeling that can result in stable, or even increased, bone density. Further clinical and basic studies are needed to confirm our unexpected findings. (C) 2011 Elsevier Inc.