Thymic Epithelial Tumors: Prognostic Significance and Relationship between Histology and the New TNM Staging System

Abstract

Background This study aims to describe the relationship between the new tumor nodes metastasis (TNM) staging and World Health Organization (WHO) classification and to identify how these two variables relate to each other and whether they possess a prognostic value in predicting survival and recurrence of disease.

Methods Medical records of 54 patients who underwent surgery for thymic epithelial tumors between 1996 and 2015 were reviewed.

The histologic type of neoplasm was classified according to the criteria of WHO and staging was evaluated using the new TNM classification system.

Results A significant correlation between the TNM stages and the histological classification was found (p < 0.001). Complete resection is related to both TNM stage and histological grading (p < 0.001). Evaluation of the 5- and 10-year survival curves shows how these are significantly correlated only at the stage (p = 0.03 and = 0.04, respectively). The risk of death at 5 and 10 years for stages III to IV is six and three times higher than in stages I to II, respectively. Regarding the disease-free survival, there is significant correlation with both staging and histology (p = 0.001 and = 0.02, respectively).

Conclusions There is a significant correlation between the new TNM staging and the histological grade WHO. The ability to implement a complete resection, the overall and disease-free survival is closely related to the thymoma stage. Furthermore, both histotype and stage correlate with disease-free survival. In fact, the least aggressive stages, both WHO and TNM, have a free time out of disease superior to advanced stages.

Keywords

thymoma - surgery - pathology - mediastinal tumor - prognosis

• References

• 1 de Jong WK, Blaauwgeers JL, Schaapveld M, Timens W, Klinkenberg TJ, Groen HJ. Thymic epithelial tumours: a population-based study of the incidence, diagnostic procedures and therapy. Eur J Cancer 2008; 44 (01) 123-130
• 2 Detterbeck FC, Stratton K, Giroux D. , et al; Staging and Prognostic Factors Committee; Members of the Advisory Boards; Participating Institutions of the Thymic Domain. The IASLC/ITMIG thymic epithelial tumors staging project: proposal for an evidence-based stage classification system for the forthcoming (8th) edition of the TNM classification of malignant tumors. J Thorac Oncol 2014; 9 (09) (Suppl. 02) S65-S72
• 3 Rami-Porta R. , Ed. Staging Manual in Thoracic Oncology. 2nd ed. North Fort Meyers (FL): Editorial Rx Press; 2016: 237-258
• 4 Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis 1987; 40 (05) 373-383
• 5 Rosai J, Sobin L. Histological typing of tumours of the thymus. In: Rosai J, Sobin L. , eds. World Health Organization, International Histological Classification of Tumours. Berlin: Springer; 1999: 9-14
• 6 Brambilla E, Müller-Hermelink HK, Harris CC. Pathology and Genetics of Tumours of the Lung, Pleura, Thymus and Heart. Lyon: IARC Press; 2004: 147
• 7 Osserman KE, Genkins G. Studies in myasthenia gravis: review of a twenty-year experience in over 1200 patients. Mt Sinai J Med 1971; 38 (06) 497-537
• 8 Ruffini E, Filosso PL, Mossetti C. , et al. Thymoma: inter-relationships among World Health Organization histology, Masaoka staging and myasthenia gravis and their independent prognostic significance: a single-centre experience. Eur J Cardiothorac Surg 2011; 40 (01) 146-153
• 9 Chen G, Marx A, Chen WH. , et al. New WHO histologic classification predicts prognosis of thymic epithelial tumors: a clinicopathologic study of 200 thymoma cases from China. Cancer 2002; 95 (02) 420-429
• 10 Quintanilla-Martinez L, Wilkins Jr EWJ, Choi N, Efird J, Hug E, Harris NL. Thymoma. Histologic subclassification is an independent prognostic factor. Cancer 1994; 74 (02) 606-617
• 11 Okumura M, Miyoshi S, Fujii Y. , et al. Clinical and functional significance of WHO classification on human thymic epithelial neoplasms: a study of 146 consecutive tumors. Am J Surg Pathol 2001; 25 (01) 103-110
• 12 Wright CD, Wain JC, Wong DR. , et al. Predictors of recurrence in thymic tumors: importance of invasion, World Health Organization histology, and size. J Thorac Cardiovasc Surg 2005; 130 (05) 1413-1421
• 13 Lucchi M, Ambrogi MC, Duranti L. , et al. Advanced stage thymomas and thymic carcinomas: results of multimodality treatments. Ann Thorac Surg 2005; 79 (06) 1840-1844
• 14 Riely GJ, Huang J. Induction therapy for locally advanced thymoma. J Thorac Oncol 2010; 5 (10) (Suppl. 04) S323-S326
• 15 Girard N, Ruffini E, Marx A, Faivre-Finn C, Peters S. ; ESMO Guidelines Committee. Thymic epithelial tumours: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol 2015; 26 (Suppl. 05) v40-v55
• 16 Margaritora S, Cesario A, Cusumano G. , et al. Thirty-five-year follow-up analysis of clinical and pathologic outcomes of thymoma surgery. Ann Thorac Surg 2010; 89 (01) 245-252 , discussion 252
• 17 Kondo K, Monden Y. Thymoma and myasthenia gravis: a clinical study of 1,089 patients from Japan. Ann Thorac Surg 2005; 79 (01) 219-224
• 18 Evoli A, Minisci C, Di Schino C. , et al. Thymoma in patients with MG: characteristics and long-term outcome. Neurology 2002; 59 (12) 1844-1850
• 19 Sanders DB, Wolfe GI, Benatar M. , et al. International consensus guidance for management of myasthenia gravis: executive summary. Neurology 2016; 87 (04) 419-425
• 20 Maggi G, Casadio C, Cavallo A, Cianci R, Molinatti M, Ruffini E. Thymectomy in myasthenia gravis. Results of 662 cases operated upon in 15 years. Eur J Cardiothorac Surg 1989; 3 (06) 504-509 , discussion 510–511
• 21 Detterbeck F, Parsons A. Thymic tumors: a review of current diagnosis, classification, and treatment. In: GA Patterson JD, Lerut A, Luketich JD, Rice JW, Pearson FG. , eds. Thoracic and Esophageal Surgery. 3rd edition. Philadelphia: Elsevier; 2008: 1589-1614
• 22 Detterbeck FC. Clinical implication of the new TNM classification of thymic malignancies. J Thorac Dis 2018; 10 (Suppl. 22) S2692-S2695
• 23 Maniscalco P, Tamburini N, Quarantotto F, Grossi W, Garelli E, Cavallesco G. Long-term outcome for early stage thymoma: comparison between thoracoscopic and open approaches. Thorac Cardiovasc Surg 2015; 63 (03) 201-205