Introduction: Clinical outcomes and prognosis of recurrent thymoma are not well known because of its rarity and indolent clinical course. This study was designed to determine the clinical outcomes and prognosis of recurrent thymoma.
Methods: Between 1986 and 2009, 41 of 305 patients who underwent resection for thymoma had recurrence. We reviewed those patients retrospectively.
Results: Of 15 patients who underwent re-resection for recurrent thymoma, 13 patients (87%) achieved complete re-resection. Of 26 patients who did not undergo re-resection, 11 patients received chemotherapy, five received chemoradiotherapy, one received another treatment, and nine patients did not receive any treatment. World Health Organization histological types AB or B1 and complete re-resection were positive prognostic factors. The complete re-resection group had better survival after recurrence than the non/incomplete re-resection group (5-year survival rate: 90.9% versus 44.7%, p = 0.014). The complete re-resection group had comparable survival after initial resection of thymoma to the patients without recurrence (5-year, 10-year survival: 91.7%, 91.7% versus 90.7%, 86.5%, p = 0.618) and better survival compared with the non/incomplete re-resection group (5-year, 10-year survival: 91.7%, 91.7% versus 81.6%, 56.7%, p = 0.018).
Conclusions: World Health Organization histologic types AB or B1 and complete re-resection are favorable prognostic factors of recurrent thymoma. In particular, complete re-resection of recurrent thymoma contributes to better survival than other management. Therefore, we suggest that long-term surveillance extended at least 20 years may be essential for early detection of recurrence to increase the chance of complete re-resection of recurrent thymoma.