Analysis of surgical treatment of Masaoka stage III-IV thymic epithelial tumors

The purpose of this study is to elucidate the outcomes after surgical resection of Masaoka stage III-IV thymic epithelial tumors.

We retrospectively reviewed patients with Masaoka stage III-IV thymic epithelial tumor who underwent surgical resection from January 1995 to January 2017. The clinicopathological features, surgical procedures, and postoperative outcomes were investigated.

Thirteen patients with thymoma and 18 patients with thymic carcinoma were assessed. The postoperative Masaoka stages were III/IVa/IVb = 8/4/1 in thymoma and III/IVa/IVb = 11/2/5 in thymic carcinoma. In patients with thymoma, the World Health Organization pathological subtypes were A/B1/B2/B3 = 2/1/4/6. We performed combined resection and reconstruction for brachiocephalic vein or superior vena cava in 3 patients with thymoma and 7 patients with thymic carcinoma. In all patients, the patency rate of the grafts was very low for the left brachiocephalic vein and well maintained for the right brachiocephalic vein. Macroscopically and pathologically complete resection was achieved in 11 and 6 patients with thymoma, respectively, and in 15 and 9 patients with thymic carcinoma, respectively. The 10-year survival rates were 85.7% in thymoma and 70.3% in thymic carcinoma. Postoperative recurrences were observed in 2 and 9 patients with thymoma and thymic carcinoma, respectively. Recurrences were observed within 5 and 10 years after surgery in 2 patients with thymoma and within 2 years in all patients with thymic carcinoma.

Patients with Masaoka stage III-IV thymic epithelial tumor showed relatively favorable long-term survival after surgical treatment. Therefore, aggressive surgical resection for complete resection may be a treatment option for these conditions.