P26.09 Is Thymomectomy alone through Video-Assisted Thoracic Surgery Appropriate for Clinical Stage I (T1N0M0) Thymoma 5cm or Less?

Abstract

The optimal mode of resection for thymoma in nonmyasthenic patients remains unclear. Resection of thymoma involves two components: mode of resection and the surgical approach. There are two modes of resection [with total thymectomy (thymothymomectomy) and without total thymectomy (thymomectomy)], and two surgical approaches (median sternotomy and minimally invasive). The aim of this study was to explore whether or not thymomectomy alone through video-assisted thoracic surgery (VATS) is a relevant option for patients with clinical stage I (T1N0M0) thymoma in the TNM classification. Between 1995 and 2019, 327 patients underwent resection for thymic epithelial tumors at National Cancer Center Hospital, Tokyo, Japan. Among them, 102 patients with clinical stage I (T1N0M0) nonmyasthenic thymoma 5cm or less who underwent thymomectomy through VATS were included in this study. We investigated surgical and oncological outcomes. The patients consisted of 44 men (43.1%) and 58 women (56.9%) with a median age of 62 years (interquartile range [IQR]: 52-69 years). All thymomectomies were performed through either complete VATS with 3 ports or hybrid VATS (incision, 5-8 cm in the fourth intercostal space at the anterior axillary line). The distribution of histologic subtype was type A (n = 17, 16.7%), type AB (n =43, 42.2%), type B1 (n = 18, 17.6%), type B2 (n = 17, 16.7%), and type B3 (n = 6.9%). The median tumor size was 3.1 cm (IQR: 2.4-4.0 cm). In terms of perioperative findings, the median blood loss was 16 ml (range: 5-30 ml) and the median operative time was 85 min (IQR: 71-103 min). Only one patient converted to open thoracotomy due to intra-operative bleeding. There were no operative deaths. The median length of the postoperative hospital stay was 3 days (IQR: 3-4 days). The morbidity rate was 0% and the 30-day mortality rate was 0%. The median follow-up time was 61 months (IQR: 23-98 months). No patients developed postoperative myasthenia gravis. Furthermore, no patients experienced a recurrence of thymoma. Hence, the 5-year freedom from recurrence was 100%. Thymomectomy alone through VATS is acceptable for clinical stage I thymoma 5cm or less with regard to both surgical and oncological outcomes. For nonmyasthenic patients with thymoma, removal of all normal thymus might be unnecessary. Further studies are needed to evaluate long-term outcomes.