Pitson Graham, Robinson Philip, Wilke Derek, Kandel Rita A, White Larry, Griffin Anthony M, Bell Robert S, Catton Charles N, Wunder Jay S, O'Sullivan Brian
Department of Radiation Oncology, Princess Margaret Hospital, Toronto, ON, Canada.
Int J Radiat Oncol Biol Phys. 2004 Oct 1;60(2):522-6. doi: 10.1016/j.ijrobp.2004.03.009.
Historically, myxoid liposarcoma (MLS) has been reported to show a marked clinical response to radiotherapy (RT), but objective data to support that contention have been lacking. We performed a retrospective analysis of the response of a group of MLS tumors to preoperative RT using tumor dimensions calculated from pretreatment imaging and the subsequent surgical specimen obtained approximately 1 month after RT.
Data were abstracted from the Princess Margaret Hospital prospective database on a series of patients with MLS who had undergone preoperative RT between 1991 and 1999. A group of malignant fibrous histiocytoma (MFH) patients treated on the same protocol served as controls. Pretreatment and posttreatment three-dimensional measurements were obtained; comparison tumor volume measurements were estimated using the ellipsoid formula, and the analysis was also repeated using the maximal tumor dimension. Identical measurement procedures were used for the MLS (experimental) and MFH (control) cases.
A total of 16 MLS tumor specimens were available for analysis, and 16 MFH cases were randomly chosen for comparison. The mean pretreatment and posttreatment volume of the MLS tumors was 415 and 199 cm(3), respectively (P = <0.0001). The mean pretreatment and posttreatment volume of the MFH tumors was 264 and 273 cm(3), respectively (p = 0.804). The proportional reduction in the median tumor volume was 59% and -7% for MLS and MFH tumors, respectively. Both the absolute and the proportional reduction in volume for MLS tumors vs. MFH tumors was statistically significant (p = 0.006 and p = 0.002, respectively).
These results provide the first objective data to support the idea that MLS tumors show a statistically significant reduction in size when treated with RT and that this response is greater than that of MFH tumors given the same RT. These results may be relevant to the management of MLS with combined RT and surgery in difficult anatomic situations in which adequate surgical excision is not feasible. They also confirm another unique characteristic of this unusual subtype of soft tissue sarcoma.
以往有报道称黏液样脂肪肉瘤（MLS）对放射治疗（RT）有显著临床反应，但一直缺乏支持该观点的客观数据。我们对一组MLS肿瘤对术前RT的反应进行了回顾性分析，使用治疗前影像学计算的肿瘤尺寸以及RT后约1个月获得的后续手术标本。
数据取自玛格丽特公主医院前瞻性数据库，该数据库记录了1991年至1999年间接受术前RT的一系列MLS患者。一组按照相同方案治疗的恶性纤维组织细胞瘤（MFH）患者作为对照。获得了治疗前和治疗后的三维测量数据；使用椭球公式估计比较肿瘤体积测量值，并使用最大肿瘤尺寸重复分析。MLS（实验组）和MFH（对照组）病例采用相同的测量程序。
共有16个MLS肿瘤标本可供分析，随机选择16例MFH病例进行比较。MLS肿瘤的平均治疗前和治疗后体积分别为415和199 cm³（P = <0.0001）。MFH肿瘤的平均治疗前和治疗后体积分别为264和273 cm³（p = 0.804）。MLS和MFH肿瘤的中位肿瘤体积比例减少分别为59%和 -7%。MLS肿瘤与MFH肿瘤相比，体积的绝对减少和比例减少均具有统计学意义（分别为p = 0.006和p = 0.002）。
这些结果提供了首个客观数据，支持以下观点：MLS肿瘤接受RT治疗后大小有统计学意义的减小，且在相同RT条件下这种反应大于MFH肿瘤。这些结果可能与在解剖结构复杂、无法进行充分手术切除的情况下联合RT和手术治疗MLS有关。它们还证实了这种不寻常的软组织肉瘤亚型的另一个独特特征。
