Thymoma size significantly affects the survival, metastasis and effectiveness of adjuvant therapies: a population based study

Abstract

BackgroundThymoma, though a rare tumor disease, is the most common tumor of the anterior mediastinum. However, tumor size, as a critical factor, has been underestimated.ResultsAge, advanced tumor stage, and preoperative radiotherapy were poor prognostic factors of overall survival (OS) and disease specific survival (DSS) (P < 0.05 for all). Besides, tumor size was significantly related to survival. The larger tumor size indicated the less OS and DSS (P < 0.001 for all). Multivariate analysis revealed elder age, advanced stage, larger size were independent adverse predictors for survival (P < 0.05 for all). Logistic analysis revealed larger tumor size had greater rate of metastasis (P < 0.001). In the group with tumors smaller than 90mm, chemotherapy was a negative predictive factor of DSS (P < 0.05 for all), and it significantly decreased OS especially with tumor sizes between 50 and 90 mm (P < 0.001).Materials and MethodsA total of 1,272 thymoma patients were enrolled from the Surveillance, Epidemiology, and End Results (SEER) database. Survival based on thymoma size and other characteristics of tumors were analyzed by univariate and multivariate analysis. Correlation between thymoma size and thymoma metastatic status was contributed by logistic regression analysis. The efficiency of adjuvant therapy was analysis by stratification analysis.ConclusionsThymoma size could predict postoperative survival and guide chemotherapeutic regimens of patients. Larger tumor size indicated worse survival and higher metastatic rate. If thymoma is smaller than 90mm, traditional chemotherapy should be prohibited. While chemotherapy could be performed moderately when thymoma larger than 90 mm.

Different View on Tumor Size Dilemma in Tumor-Node-Metastasis Staging System for Thymoma

“…Moreover, there are also few studies on the relationship between tumor size and survival of thymic epithelial tumors in the literature. [19][20][21][24][25][26] In some of these studies, tumor size was reported to be a prognostic factor and patients with large size tumors (>10 or >8 cm) were determined to have significantly worse survival outcome as compared with those with smaller tumors. 19,21,[26][27][28] On the other hand, in the study based on the European Society of Thoracic Surgeons' (ESTS) database, tumor size was not reported to be a prognostic factor.…”

“…There are a few previous publications in the literature reporting that the tumor size is a prognostic factor in thymic malignancies; however, in these publications different size cut-offs have been used. 16,[19][20][21][24][25][26] In the present study, to better reveal the effect of size on prognosis in thymic tumors that are usually nonspherical lesions; a design that takes into account the effect of the shortest tumor diameter on survival, as well as the longest tumor diameter was used.…”

“…Few studies have focused on the impact of tumor size for thymic malignancies. 16,[19][20][21] Thus, the role of tumor size and its prognostic effect are still vague in thymic tumors.…”

Commentary: Thymic epithelial tumors—time to move beyond traditional staging?

“…Similarly, a Surveillance, Epidemiology, and End Results database review demonstrated stepwise decrements in survival with increasing tumor size. 4 In contrast, Nicholson and colleagues 5 analyzed multiple international databases and demonstrated that size was only predictive among Masaoka-Koga stage III-IV tumors with incomplete resections. Other staging characteristics were more predictive of outcomes, with size playing only a minor role, and the tumor size did not correlate with the ability to perform a complete resection.…”

The thymoma tale

“…Hence, to have an idea of the actual distribution, there is a need to have multi-institutional collaborations with thymomas in sufficient numbers. It would also be important to follow a protocol8 for clinicoradiological, gross and histological assessment of such tumours, as there are some studies indicating that even tumour sizes are useful in predicting prognosis9.…”