Pigott K H, Baddeley H, Maher E J
Mount Vernon Hospital, Northwood, Middlesex, UK.
Clin Oncol (R Coll Radiol). 1994;6(1):7-10. doi: 10.1016/s0936-6555(05)80361-9.
Recent trends in the management of bone metastases include the use of prophylactic bisphosphonates and low dose single fraction radiotherapy in favour of high dose fractionated radiotherapy. A recent animal model [1] suggests that cord compression is often associated with predominant soft tissue epidural disease, with bone collapse as a late event. In the present study, potential implications were investigated by retrospective evaluation of the pattern of disease on MRI scans of patients with spinal cord compression. The dominant component of spinal cord compression was determined in 62 patients. Two main patterns were identified, 45 (73%) had predominant soft tissue epidural disease and 15 (24%) had bone collapse. There were two with intrathecal deposits. The patterns were correlated with response to radiotherapy. Positive response was observed in 64% of those with soft tissue epidural disease and 27% of those with bone collapse. These data support the animal model, suggesting soft tissue epidural disease rather than collapse as the predominant cause of cord compression. This implies that prophylactic bisphosphonates alone would be unlikely to reduce the incidence of spinal cord compression. It also introduces concern about the long term safety of low dose single fraction radiotherapy for bone metastases in patients with a medium term life expectancy (e.g. > 2 years). These patients may benefit from more than a single fraction of radiotherapy to produce longer growth delay for sub-clinical epidural disease.
骨转移瘤治疗的最新趋势包括使用预防性双膦酸盐和低剂量单次分割放疗，而不是高剂量分割放疗。最近的一个动物模型[1]表明，脊髓压迫通常与主要的软组织硬膜外病变相关，而骨塌陷是晚期事件。在本研究中，通过回顾性评估脊髓压迫患者MRI扫描的疾病模式来研究潜在影响。确定了62例患者脊髓压迫的主要成分。识别出两种主要模式，45例（73%）主要为软组织硬膜外病变，15例（24%）有骨塌陷。有2例有鞘内沉积物。这些模式与放疗反应相关。软组织硬膜外病变患者中有64%观察到阳性反应，骨塌陷患者中有27%观察到阳性反应。这些数据支持该动物模型，表明软组织硬膜外病变而非塌陷是脊髓压迫的主要原因。这意味着单独使用预防性双膦酸盐不太可能降低脊髓压迫的发生率。这也引发了对中期预期寿命（如>2年）患者低剂量单次分割放疗治疗骨转移瘤长期安全性的担忧。这些患者可能受益于不止一次分割的放疗，以便为亚临床硬膜外病变产生更长的生长延迟。
