Thymic epithelial malignancies are rare tumors. There have been many obstacles to progress in these diseases. Among these has been the lack of an official, consistent stage classification system put forth by the American Joint Committee on Cancer (AJCC) and the Union for International Cancer Control (UICC) —the bodies responsible for defining stage classification throughout the world. At least 15 different stage classification systems have been proposed and used.¹ x 1 Filosso, P, Ruffini, E, Lausi, P, Lucchi, M, Oliaro, A, and Detterbeck, F. Historical perspectives: the evolution of the thymic epithelial tumors staging system. Lung Cancer. 2014; 83: 126–132 Abstract | Full Text | Full Text PDF | PubMed | Scopus (27) | Google Scholar See all References These have been largely empirically derived, based on data from small numbers of patients. Perhaps the most widely used have been the Masaoka classification (derived from data on 91 patients),² x 2 Masaoka, A, Monden, Y, Nakahara, K, and Tanioka, T. Follow-up study of thymomas with special reference to their clinical stages. Cancer. 1981; 48: 2485–2492 Crossref | PubMed | Scopus (1191) | Google Scholar See all References and the Koga modification of this (based on 76 patients).³ x 3 Koga, K, Matsuno, Y, Noguchi, M et al. A review of 79 thymomas: modification of staging system and reappraisal of conventional division into invasive and non-invasive thymoma. Pathol Int. 1994; 44: 359–367 Crossref | PubMed | Scopus (211) | Google Scholar See all References Even among centers using one of these classification systems, often the definitions have been interpreted differently because of vague wording, thus hampering the ability to collaborate effectively.⁴ x 4 Detterbeck, FC, Moran, C, Huang, J et al. Which way is up? Policies and procedures for surgeons and pathologists regarding resection specimens of thymic malignancy. J Thorac Oncol. 2011; 6: S1730–S1738 Abstract | Full Text | Full Text PDF | PubMed | Scopus (63) | Google Scholar See all References

Background: Tumors acquire nutrients that are essential for continued growth and an avenue for dissemination to the rest of the body by inducing angiogenesis (i.e., the formation of new blood vessels). Preliminary studies involving a number of different kinds of cancer have indicated that an assessment of tumor angiogenesis may be useful in predicting disease outcome. Purpose: In a prospective study, we evaluated the relationship between tumor angiogenesis and survival for 407 patients with nonsmall- cell lung carcinoma who were treated with potentially curative surgery. Methods: The study population consisted of 360 male and 47 female patients who underwent surgery consecutively at the Department of Surgery, University of Pisa, Italy, from March 1991 through December 1994. Followup lasted through February 1996, with a median follow-up for living patients of 29 months (range, 15-60 months). An anti-CD34 monoclonal antibody, which is specific for endothelial cells, and standard immunohistochemical techniques were used to measure angiogenesis in tumor samples. Angiogenesis was quantified in terms of microvessel counts; the counts for single, highpower microscopic fields (magnification ×250) in the three most intense areas of blood vessel growth for each sample were averaged. The median microvessel count in this series was 20, and the counts were categorized as follows: 1) low versus high (⩽20 versus >20 microvessels) or 2) in five categories (1-10, 11-20, 21-30, 31-40, and ⩾41 microvessels). Disease-free and overall survival during follow-up were assessed. Kaplan-Meier survival curves were modeled in a univariate analysis of patient and tumor characteristics; the Cox proportional hazards model was used in multivariate analysis. Reported P values are two-sided. Results and Conclusions: In the univariate analysis, patients with larger tumors ( P for trend <.00001), a more advanced tumor stage ( P for trend <.00001), a greater degree of regional lymph node involvement (P for trend <.00001), or more vascularized tumors (high versus low microvessel count, P <.00001) experienced significantly reduced overall survival. When microvessel counts were analyzed in five categories, a highly significant trend ( P <.00001) toward worse prognosis was observed with increasing tumor vascularity. In multivariate analysis, tumor microvessel count ( P <.00001), tumor size ( P = .0006), and regional lymph node status ( P <.00001) retained independent prognostic value with respect to overall survival; among these variables, tumor microvessel count, considered as a continuous variable, was the most important, with a relative hazard of death of 8.38 (95% confidence interval = 4.19- 16.78) associated with the highest microvessel counts. Implications: An evaluation of tumor angiogenesis may be useful in the postsurgical staging of patients with non-small-cell lung carcinoma and in identifying subsets of patients who may benefit from different postsurgical treatments.