Predictors of survival following surgical resection of thymoma

Abstract

The aim of this study was to determine the predictors of long-term survival following surgical resection of thymoma. Forty-one patients with a histologically proven diagnosis of thymoma were evaluated and treated over a 30-year period (1961 to 1991) at our institution. Seven patients (Masaoka stage III or IV) were unresectable and were treated by radiotherapy and/or chemotherapy, with an overall 5 year survival of 50%. Thirty-four patients underwent primary surgical excision of the thymoma, most often through a median sternotomy, with 5- and 10-year survivals of 90%. Complete excision of the thymoma was achieved in 31 patients with a median survival of 54 months vs. 17 months if incomplete. Independent prognostic factors influencing survival were stage, histology, and patients judged to have a benign thymoma at surgery. Although the thymoma was associated with myasthenia gravis (8 patients) and second primary cancers (8 patients), neither factor was associated with overall survival. We conclude that the most significant predictors of long-term survival of thymoma include complete excision, Masaoka stage I disease, and lymphocytic histology. Multivariate analysis suggested that postoperative chemoradiotherapy may impact on survival.

Clinical and Pathologic Predictors of Survival in Patients With Thymoma

“…4 The 3% of the patients with associated pure red cell aplasia is comparable to the proportions reported in other series. 6,9,11,12,15 The overall survival rate of the patients in this series was similar to that reported in other series. [5][6][7][8][9][10][11]13,14,26 Forty-four percent of the patients were dead at the conclusion of the study, but, strikingly, less than a third (32%) of these deaths were thymoma-related.…”

“…Marino and Müller-Hermelink histologically graded thymomas based on their differentiation toward normal thymic cortical or medullary epithelium. 18 -20 Although predominantly epithelial 5,6,8,9,12 and cortical 10,14,15,18,[21][22][23][24][25][26][27] thymomas have been described as more invasive tumors, the importance of histologic classification as an independent predictor of overall prognosis remains unclear.…”

“…[5][6][7][8][9][10][11][13][14][15] Although most of the patients had local symptoms, a significant number were asymptomatic or had the thymoma diagnosed during a routine chest x-ray. The 40% incidence of MG seen here, higher than the 25% to 35% reported in most other series, 14,15,26,27,31,32 is probably because of the large number of patients referred to the Johns Hopkins Hospital primarily for the neurologic management and surgical treatment (thymectomy) of MG per se.…”

“…[3][4][5][6][7][8] Several studies have indicated the importance of initial tumor invasion and the extent of surgical resection as predictors of recurrence and survival after resection of a thymoma. [5][6][7][8][9][10][11][12][13][14][15] The most widely employed system for clinical staging at initial presentation is that proposed by Masaoka (Table 1). Stage I tumors are completely encapsulated, both grossly and microscopically.…”

“…This also indicates that patients must be followed for many years because it is not unusual for patients to present more than 10 years after resection with late recurrence or even death. 5,6,8 Several retrospective studies have attempted to define clinicopathologic variables that can be used to predict prognosis in patients with thymoma. However, many of these series contain inadequate numbers of patients to allow the quantitation of the independent prognostic value of these variables.…”