Optimal therapy for thymoma

Abstract

: Thymoma is the most common tumor of the anterior mediastinum. This tumor is associated with unique paraneoplastic syndromes (myasthenia gravis, pure red cell aplasia, hypogammaglobulinemia, and other autoimmune diseases). The rarity of this tumor has somewhat obscured the optimal treatment. Although the histologic classification of thymoma has remained a subject of controversy for many years, the WHO classification system, published in 1999, appeared to be an advance in our understanding of thymoma. The optimal treatment for thymoma depends on its clinical stage. Surgery remains the mainstay of treatment for thymic epithelial tumors. Thymomas also have a high response rate to chemotherapy or radiotherapy. Only surgical resection is performed for patients with stage I (non-invasive) thymoma. The value of postoperative radiotherapy in completely resected stage II or III tumors is questionable. Multimodality therapy involving surgery, chemotherapy and radiotherapy appears to increase the rate of complete resection and survival in advanced (stage III and IV) thymomas. J. Med. Invest. 55 : 17-28,

Thymomas and Thymic Carcinomas

“…Total thymectomy and complete surgical excision of the tumor are the gold standard of treatment and are recommended whenever possible for most resectable tumors (see "Principles of Surgical Resection," page 567). 4,5,9,20,21 During thymectomy, the pleural surfaces should be examined for metastases. To achieve a complete gross resection, removal of pleural metastases may be appropriate in some patients.…”

“…48,[52][53][54] Adjuvant therapy is not recommended for completely resected (R0) stage I thymomas. 20,55,56 For incompletely resected thymomas, postoperative radiation therapy (RT) is recommended (see "Postoperative Management," page 565). 20,57 Note that extensive elective nodal radiation is not recommended, because thymomas do not typically metastasize to regional lymph nodes.…”

Prognostic value of preoperative neutrophil-lymphocyte ratio is superior to platelet-lymphocyte ratio for survival in patients who underwent complete resection of thymic carcinoma

“…The complete resection (R0) is the gold standard treatment for operable thymic carcinoma. Radiotherapy and chemotherapy appear to benefit inoperable or incompletely resected patients (6)(7)(8).…”

Thymoma and autoimmunity

“…3 Currently, two means of thymoma classification are used for clinical staging and prognostic evaluations. 4 The first is the WHO classification published in 1999, which utilizes microscopic histological criteria (Table 1), and the second is that performed by Masaoka, which uses macroscopic and microscopic criteria. 3 The current treatment regimen and prognosis for patients diagnosed with thymoma varies according to the stage or subtype of each classification system.…”