Lawrence W, Anderson J R, Gehan E A, Maurer H
Division of Surgical Oncology and Massey Cancer Center, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298, USA.
Cancer. 1997 Sep 15;80(6):1165-70.
The Intergroup Rhabdomyosarcoma Study Group (IRSG) studies began in 1972 and initially used a clinicopathologic system to place patients into prognostic groups. Because of interest in the development of a pretreatment staging system for assessing the posttreatment outcomes of patients with this disease, potential staging elements were retrospectively evaluated in a subset of 505 patients who participated in IRS-II, an IRSG clinical trial.
Using the IRS-II data, a TNM pretreatment staging system was developed and used to stage prospectively the patients who were entering IRS-III, a subsequent treatment protocol of the IRSG. Failure free survival and overall survival were compared by pretreatment stage in IRS-III as a means of evaluating this TNM staging.
The TNM staging system described the tumor (T) in terms of lesion size (< 5 cm or > or = 5 cm) instead of invasiveness, because these two features were not independent of each other. The clinical status of regional lymph nodes (N) was included in the staging system, as was the presence or absence of metastatic disease (M). The latter feature was extremely important, as expected. The anatomic site of the primary tumor also proved to be an important staging element. Classification of patients by tumor size, clinical status of regional lymph nodes, presence or absence of metastatic disease, and location of the primary tumor (at a favorable or unfavorable anatomic site) created four prognostically distinct staging categories that were relatively equal in size. In a prospective evaluation of this staging system with IRS-III patients, the pretreatment staging lost some prognostic impact. The survival of patients with smaller lesions at unfavorable anatomic sites without clinically involved lymph nodes (Stage II) was similar to that of patients with primary tumors at favorable anatomic sites (Stage I).
A pretreatment TNM staging system for childhood rhabdomyosarcoma, developed with data from IRS-II, was not as predictive of patient outcome when applied prospectively to patients treated in the IRS-III trial. These findings could be due to differences in the management strategy used for IRS-III or the statistical variability in the model-fitting process used to develop the staging system. This demonstrates the need for continual reevaluation of staging systems as patient evaluation and treatment innovations are developed.
横纹肌肉瘤协作组（IRSG）研究始于1972年，最初使用临床病理系统将患者分为不同预后组。由于人们对开发一种用于评估该疾病患者治疗后结局的治疗前分期系统感兴趣，因此对参与IRSG临床试验IRSG-II的505例患者的子集进行了潜在分期因素的回顾性评估。
利用IRSG-II的数据，开发了一种TNM治疗前分期系统，并用于对即将进入IRSG后续治疗方案IRSG-III的患者进行前瞻性分期。通过IRSG-III中的治疗前分期比较无病生存率和总生存率，以此评估该TNM分期。
TNM分期系统根据病变大小（<5 cm或≥5 cm）而非侵袭性来描述肿瘤（T），因为这两个特征并非相互独立。区域淋巴结的临床状态（N）以及是否存在转移性疾病（M）均纳入分期系统。正如预期的那样，后一个特征极其重要。原发肿瘤的解剖部位也被证明是一个重要的分期因素。根据肿瘤大小、区域淋巴结临床状态、是否存在转移性疾病以及原发肿瘤位置（解剖部位有利或不利）对患者进行分类，产生了四个预后明显不同且大小相对相等的分期类别。在对IRSG-III患者进行的该分期系统前瞻性评估中，治疗前分期失去了一些预后影响。在解剖部位不利且无临床受累淋巴结（II期）的较小病变患者的生存率与解剖部位有利的原发肿瘤患者（I期）相似。
利用IRSG-II数据开发的儿童横纹肌肉瘤治疗前TNM分期系统，在对接受IRSG-III试验治疗的患者进行前瞻性应用时，对患者结局的预测性不如预期。这些发现可能是由于IRSG-III使用的管理策略不同，或者是开发分期系统所采用的模型拟合过程中的统计变异性所致。这表明随着患者评估和治疗创新的发展，需要对分期系统进行持续重新评估。
