Okumura Meinoshin, Ohta Mitsunori, Tateyama Hisashi, Nakagawa Katsuhiro, Matsumura Akihide, Maeda Hajime, Tada Hiroto, Eimoto Tadaaki, Matsuda Hikaru, Masaoka Akira
Division of General Thoracic Surgery, Department of Surgery, Osaka University Graduate School of Medicine, Osaka, Japan.
Cancer. 2002 Feb 1;94(3):624-32. doi: 10.1002/cncr.10226.
Although the histologic classification of thymic epithelial tumors has been confusing and controversial, an agreement on the universal classification system for thymic epithelial tumors was achieved by the World Health Organization (WHO) in 1999. The authors previously reported that the WHO histologic classification system reflects invasiveness and immunologic function of thymic epithelial tumors. In this subsequent study, they examined the prognostic significance of this classification system.
Clinical features as well as postoperative survival of patients with thymoma, but not thymic carcinoma, were examined with reference to WHO histologic classification based on an experience with 273 patients over a 44-year period.
There were 18 type A tumors, 77 type AB tumors, 55 type B1 tumors, 97 type B2 tumors, and 26 type B3 tumors. In patients with type A, AB, B1, B2, and B3 tumors, the respective proportions of invasive tumor were 11.1%, 41.6%, 47.3%, 69.1%, and 84.6%; the respective proportions of tumors with involvement of the great vessels were 0%, 3.9%, 7.3%, 17.5%, and 19.2%; and the respective 20-year survival rates were 100%, 87%, 91%, 59%, and 36%. According to the Masaoka staging system, the 20-year survival rates were 89%, 91%, 49%, 0%, and 0% in patients with Stage I, II, III, IVa, and IVb disease, respectively. By multivariate analysis, the Masaoka staging system and the WHO histologic classification system were significant independent prognostic factors, whereas age, gender, association with myasthenia gravis, completeness of resection, or involvement of the great vessels were not significant independent prognostic factors.
This study showed that histologic appearance reflects the oncologic behavior of thymoma when the WHO classification system is adopted. The WHO classification system may be helpful in clinical practice for the assessment and treatment of patients with thymoma.
尽管胸腺上皮肿瘤的组织学分类一直令人困惑且存在争议，但世界卫生组织（WHO）于1999年达成了关于胸腺上皮肿瘤通用分类系统的共识。作者此前报道，WHO组织学分类系统反映了胸腺上皮肿瘤的侵袭性和免疫功能。在这项后续研究中，他们检验了该分类系统的预后意义。
基于44年间273例患者的经验，参照WHO组织学分类，对胸腺瘤（而非胸腺癌）患者的临床特征及术后生存率进行了研究。
有18例A型肿瘤、77例AB型肿瘤、55例B1型肿瘤、97例B2型肿瘤和26例B3型肿瘤。在A型、AB型、B1型、B2型和B3型肿瘤患者中，侵袭性肿瘤的比例分别为11.1%、41.6%、47.3%、69.1%和84.6%；累及大血管的肿瘤比例分别为0%、3.9%、7.3%、17.5%和19.2%；20年生存率分别为100%、87%、91%、59%和36%。根据Masaoka分期系统，I期、II期、III期、IVa期和IVb期疾病患者的20年生存率分别为89%、91%、49%、0%和0%。多因素分析显示，Masaoka分期系统和WHO组织学分类系统是显著的独立预后因素，而年龄、性别、合并重症肌无力、切除完整性或累及大血管并非显著的独立预后因素。
本研究表明，采用WHO分类系统时，组织学表现反映了胸腺瘤的肿瘤行为。WHO分类系统可能有助于胸腺瘤患者的临床评估和治疗。
