Treatment Modalities and Outcomes in Patients With Advanced Invasive Thymoma or Thymic Carcinoma: A Retrospective Multicenter Study.

INTRODUCTION: We investigated the relationships between treatment characteristics and long-term outcomes in patients with locally advanced thymoma or thymic carcinoma. METHODS: We retrospectively reviewed 146 patients treated from 1980 to 2011 at 2 tertiary cancer care centers, 110 with Masaoka-Koga stages III to IVA invasive thymoma and 36 with stages I to IVA thymic carcinoma. Survival probabilities were estimated using the Kaplan-Meier method. Risk factors related to survival were identified by univariate and multivariate competing risk analysis, with overall survival (OS) as the competing risk. The Cox regression analysis was used to identify risk factors for OS. RESULTS: Median follow-up time for all patients was 64 months. At 5 and 10 years, rates of OS and freedom from recurrence (FFR) were 81% and 58% and 81% and 65%, respectively. Of the patients who underwent surgery, trimodality treatment produced better survival compared with less aggressive treatment among patients with stage III disease (P=0.03). Among patients who underwent trimodality treatment, patients with stage III disease had better OS (P=0.03) and FFR (P<0.001) than those with stage IVA disease. On Cox regression analysis, decreased OS was associated with thymic carcinoma (hazard ratio [HR], 7.36; 95% confidence interval [CI], 2.38-22.77; P=0.001), R2/unresectable disease (HR, 8.45; 95% CI, 1.44-49.42; P=0.02), and an Eastern Cooperative Oncology Group performance score of 1 (HR, 8.14; 95% CI, 1.55-42.75; P=0.01) or 2 to 3 (HR, 29.60; 95% CI, 4.0-218.98; P=0.001) versus 0. CONCLUSIONS: Aggressive treatment with chemotherapy, surgical resection, and postoperative radiation therapy can produce long-term survival for patients with invasive thymic malignancies.