Background: It is so far not clear that how myasthenia gravis (MG) affected the prognosis of thymoma patients. The aim of this assay is to compare the postoperative survival between patients with thymoma only and those with both thymoma and MG.
Methods: The Chinese Alliance for Research in Thymomas (ChART) registry recruited patients with thymoma from 18 centers over the country on an intention to treat basis from 1992 to 2012. Two groups were formed according to whether the patient complicated MG. Demographic and clinical data were reviewed, Patients were followed and their survival status were analyzed.
Results: There were 1,850 patients included in this study, including 421 with and 1,429 without MG. Complete thymectomy were done in 91.2% patients in MG group and 71.0% in non-MG group (P<0.05). There were more percentage of patients with the histology of thymoma AB, B1, or B2 (P<0.05) in MG group, and more percentage of patients with MG were in Masaoka stage I and II. The 5 year and 10 year OS rates were both higher in MG group (93% vs 88%; 83% vs 81%, P=0.034) respectively. The survival rate was significantly higher in patients with MG when the Masaoka staging was III/IV (P=0.003). Among patients with advanced stage thymoma (stage III, IVa, IVb), the constituent ratios of III, IVa, IVb were similar between MG and Non-MG group. Histologically, however, there were significantly more proportion of AB/B1/B2/B3 in the MG group while there were more C in the non-MG group (P=0.000). Univariate analyses for all patients showed that MG, WHO classification, Masaoka stage, surgical approach, chemotherapy and radiotherapy and resectability were significant factors, and multivariate analysis showed WHO Classification, Masaoka stage, and resectability were strong independent prognostic indicators.
Conclusions: Although MG is not an independent prognostic factor, the survival of patients with thymoma was superior when MG was present, especially in late Masaoka stage patients. Possible reasons included early diagnosis of the tumor, better histologic types, an overall higher R0 resection and less recurrence. .
背景与目的 重症肌无力（myasthenia gravis, MG）对胸腺瘤患者预后的影响至今尚不明确，本文旨在比较单纯胸腺瘤与合并肌无力胸腺瘤患者的手术预后。方法 1992年至2012年中国胸腺协作组（Chinese Alliance for Research in Thymomas, ChART）数据库录入的18个胸外科中心诊断胸腺瘤并接受相关手术的患者分为合并重症肌无力组（合并组）和单纯胸腺瘤组（对照组）。收集两组患者的人口学资料及临床资料，比较两组患者生存率。结果 共1,850例患者纳入研究，其中合并肌无力组及单纯胸腺瘤组分别421人和1429人，行胸腺全切的比例分别是91.2%和71.0%（P<0.05）；肌无力组患者的WHO病理类型多分布于AB、B1和B2型，优于单纯胸腺瘤组（P<0.05）；合并肌无力组的Masaoka分期较早（I和II期）的比例高于单纯胸腺瘤组。5年和10年的总体生存率在MG组和非MG组中分别为93%和88%; 83%和81%（P=0.034）；在Masaoka III、IVa和IVb期胸腺瘤患者中，合并肌无力患者的生存曲线高于单纯胸腺瘤患者（P=0.003）。在进展型胸腺瘤患者中，MG组和非MG组患者的Masaoka III、IVa、IVb的构成比相似，组织学结果中，MG组的AB/B1/B2/B3型的比例高于C型比例更高的非MG组（P<0.001）。整体的单因素分析结果提示，MG、WHO分型、Masaoka分期、手术方式、化疗、放疗和临床切除状况均为预后的影响因素。而在多因素分析中，WHO分型、Masaoka分期和临床切除状况是独立的预后预测指标。结论 虽然重症肌无力不是独立的预后影响因素，但是在胸腺瘤患者中，合并MG的患者预后较优，尤其是Masaoka分期晚期的患者，可能与疾病的早期发现、病理类型分布相对较好、整体R0切除率较高以及复发率较低有关。.