Thymic epithelial neoplasms: a 12-year Canadian regional cancer program experience

Thymic epithelial neoplasms are rare, with little prospective research to guide management. Surgery is the primary treatment modality for localized disease, but chemotherapy may be indicated in advanced disease. We performed a retrospective chart review of all cases over a 12-year period at our institution.

With ethics approval, data collected included patient characteristics, histologic type (World Health Organization [WHO] criteria), staging (Masaoka system), paraneoplastic syndromes, treatment details, and outcomes. The primary analysis is descriptive.

Thymic epithelial neoplasms were identified in 76 patients: 46% women with a median age 60 years (range, 25-89 years), 93% with Eastern Cooperative Oncology Group performance status of 0 to 1. Myasthenia gravis was present in 21%. The distribution by WHO histologic classification was A, 15%; AB, 30%; B1, 16%; B2, 13%; B3, 17%; C, 7%; neuroendocrine thymic tumor (NETT), 1%; and unclassified, 1%. Of 64 patients who underwent operation, 53 underwent R0 resection. Eleven surgical patients received chemotherapy (induction, n = 6; adjuvant, n = 4; both, n = 1) and 27 received radiotherapy (induction, n = 2; adjuvant, n = 25). Twelve patients were not considered for surgery, and 3 patients received no therapy at all. Chemotherapy was received at some point in the disease course in 14 patients. Common first-line regimens were platinum/etoposide (n = 8), carboplatin/paclitaxel (n = 3), and CAP (cyclophosphamide, doxorubicin [Adriamycin], cisplatin [n = 2]). The first-line response rate (Response Evaluation in Solid Tumors [RECIST]) was 55%. After a median follow-up of 45 months, 59 (78%) patients remain alive. Thymoma was associated with superior overall survival compared with thymic carcinoma (P < .0001).

Although surgical resection is the mainstay of treatment for thymic epithelial neoplasms, it remains clear that these are chemosensitive diseases.