Ji Tao, Guo Wei, Yang Rongli, Tang Xiaodong, Wang Yifei, Huang Lin
Musculoskeletal Tumor Center, People's Hospital, Peking University, Beijing, China.
Clin Orthop Relat Res. 2017 Mar;475(3):620-630. doi: 10.1007/s11999-016-4773-8.
Conditional survival is a measure of prognosis for patients who have already survived for a specific period of time; however, data on conditional survival after sacrectomy in patients with sacral chordoma are lacking. In addition, because sacral tumors are rare and heterogeneous, classifying them in a way that allows physicians to predict functional outcomes after sacrectomy remains a challenge.
QUESTIONS/PURPOSES: (1) What is the overall survival and disease-free survival in patients treated by sacrectomy for chordoma? (2) What is the conditional survival probability and how do prognostic factors change over time in patients undergoing surgical resection for sacral chordoma? (3) What is the local recurrence rate after surgery, how was it treated, and what factors impact on local recurrence? (4) What is the postoperative motor, sensory, bowel, and bladder function by level of resection as determined by using a newly designed scoring method?
Between 2003 and 2012, our center treated 122 patients surgically for sacral chordoma. Of those, two died and five were lost before a minimum followup of 1 year was achieved, leaving 115 patients available for analysis in this retrospective study at a mean of 4.9 years (range, 1.3-10.8 years). Basically, single posterior or combined approaches were chosen based on the most cephalad extent of the tumor and resection level was normally at half or one sacral vertebrae above the tumor. The 5-year conditional survival rate was calculated based on Kaplan-Meier survival analysis. The effect of prognostic factors on conditional survival was also explored. A newly designed score method was proposed and adopted in the current study to critically evaluate the functional outcome after resection of the sacrum. Inter- and intraobserver reliability was tested by a preliminary study using kappa statistics and Spearman rank correlation coefficients. Significant interobserver (p < 0.01) and intraobserver agreement (κ > 0.75) were found in nine items between each observer.
The estimated 5-year overall survival rate was 81% (95% confidence interval [CI], 72%-90%) at diagnosis. The 5-year disease-free survival rate was 52% (95% CI, 43%-63%). The 5-year conditional overall survival decreased with each additional year in the first 4 years (81% at diagnosis versus 60% at the fourth year, p < 0.0001) and increased slightly in the fifth year. Patients with adequate surgical margins displayed a higher 5-year survival than those with an inadequate margin (86% [95% CI, 76%-95%] versus 67% [95% CI, 48%-85%], p = 0.01) at diagnosis. Conditional survival estimates for patients who received operations elsewhere were lower than that of newly diagnosed patients treated by us at diagnosis (64% [95% CI, 46%-83%] versus 90% [95% CI, 82%-99%], p = 0.012), but with the numbers we had, we could not detect a difference in conditional survival between those treated elsewhere first compared with those initially treated by us at 5 years. The proposed score system for function evaluation was able to distinguish different levels of resection. The overall functional results for the preservation of bilateral S1, S2, and S3 were 40 ± 8%, 60 ± 12%, and 82 ± 11%, respectively. Patients who had preservation of only one S3 nerve root had more severe incontinence (1.99 ± 0.79 versus 2.60 ± 0.63, p = 0.01) and more sensory loss (1.88 ± 0.82 versus 2.31 ± 0.59, p = 0.02) than those patients with preservation of bilateral S3 nerve roots.
The 5-year conditional survival for sacral chordoma decreased with each additional year and began to improve after the fourth year. In addition, the effect of the surgical margin and influence of previous surgery on conditional survival were not linear over time. The level of nerve root resections corresponded with the overall function scores according to the proposed scoring method. This information and scoring system should be valuable in discussing outcomes of sacrectomy in patients with chordoma who are considering this operation and serve as the basis for further study.
Level III, therapeutic study.
条件生存率是衡量已存活特定时间段患者预后的指标；然而，骶骨脊索瘤患者骶骨切除术后的条件生存数据尚缺。此外，由于骶骨肿瘤罕见且具有异质性，以一种能让医生预测骶骨切除术后功能结局的方式对其进行分类仍是一项挑战。
问题/目的：（1）骶骨脊索瘤患者行骶骨切除术后的总生存率和无病生存率是多少？（2）骶骨脊索瘤手术切除患者的条件生存概率是多少，预后因素如何随时间变化？（3）术后局部复发率是多少，如何治疗，哪些因素影响局部复发？（4）采用新设计的评分方法确定，按切除水平划分的术后运动、感觉、肠道和膀胱功能如何？
2003年至2012年，我们中心对122例骶骨脊索瘤患者进行了手术治疗。其中，2例死亡，5例在未达到至少1年随访时失访，本回顾性研究中剩余115例患者可供分析，平均随访4.9年（范围1.3 - 10.8年）。基本上，根据肿瘤最上端范围选择单一后路或联合入路，切除水平通常在肿瘤上方半个或一个骶椎。基于Kaplan - Meier生存分析计算5年条件生存率。还探讨了预后因素对条件生存的影响。本研究提出并采用一种新设计的评分方法来严格评估骶骨切除术后的功能结局。通过使用kappa统计量和Spearman等级相关系数的初步研究测试了观察者间和观察者内的可靠性。各观察者之间在9项指标上发现了显著的观察者间一致性（p < 0.01）和观察者内一致性（κ > 0.75）。
诊断时估计的5年总生存率为81%（95%置信区间[CI]，72% - 90%）。5年无病生存率为52%（95%CI，43% - 63%）。在最初4年中，5年条件总生存率逐年下降（诊断时为81%，第4年为60%，p < 0.0001），第5年略有上升。手术切缘充分的患者在诊断时的5年生存率高于切缘不充分的患者（86%[95%CI，76% - 95%]对67%[95%CI，48% - 85%]，p = 0.01）。在其他地方接受手术的患者的条件生存估计低于我们诊断时新诊断的患者（64%[95%CI，46% - 83%]对90%[95%CI，82% - 99%]，p = 0.012），但鉴于我们的数据量，我们无法检测出先在其他地方治疗的患者与最初由我们治疗的患者在5年时的条件生存差异。所提出的功能评估评分系统能够区分不同的切除水平。保留双侧S1、S2和S3的总体功能结果分别为40 ± 8%、60 ± 12%和82 ± 11%。仅保留一条S3神经根的患者比保留双侧S3神经根的患者有更严重的尿失禁（1.99 ± 0.79对2.60 ± 0.63，p = 0.01）和更多的感觉丧失（1.88 ± 0.82对2.31 ± 0.59，p = 0.02）。
骶骨脊索瘤的5年条件生存率逐年下降，第4年后开始改善。此外，手术切缘和既往手术对条件生存的影响随时间并非呈线性。根据所提出的评分方法，神经根切除水平与总体功能评分相对应。这些信息和评分系统对于讨论考虑该手术的脊索瘤患者骶骨切除的结局应具有价值，并可为进一步研究提供基础。
III级，治疗性研究。
