胸腺腫に対する低侵襲手術の妥当性

Validity of Video-assisted Thoracic Surgery for Thymoma

胸腺腫に対する胸腔鏡補助下手術は，その低侵襲性の観点からすでに多くの施設で普及している．しかし，報告が小病変に対する後方視研究にとどまること，長期成績が明らかでないことから，ガイドライン上，その適応は弱い推奨でエビデンスの強さもCにとどまっている1）．また，重症筋無力症合併胸腺腫に対する拡大胸腺摘出術について，胸腔鏡補助下手術による症状改善率の報告がみられるが2），そのエビデンスは十分とされていない1）．

Objectives：This study aimed to identify the validity of video-assisted thoracic surgery （VATS） for thymoma, including myasthenia gravis （MG）.

Methods：A total of 20 patients who underwent VATS for thymoma at our institution between 2011 and 2019 were included in the study. Preoperative complications and prognosis were analyzed to detect the safety and efficiency of VATS thymectomy. MG improvement after VATS extended thymectomy was evaluated using a quantitative myasthenia gravis score （QMGS） and Myasthenia Gravis Foundation of America post-intervention status （MGFA-PIS）.

Results：The median tumor size was 2.6 cm （range, 1.0-8.0 cm）. All thymomas were classified as TNM stageⅠ. Two patients had type A thymoma, five had type AB, six had type B1, six had type B2, and one had type B3. Postoperative complications were only observed in one patient with pneumonia. The median follow-up period was 5.1 years；no recurrence and disease-related deaths were observed. However, three patients died of other diseases. In patients with MG, postoperative crisis was not observed, and the symptoms improved in all the patients as evaluated by QMGS and MGFA-PIS.

Conclusions：VATS thymectomy and VATS extended thymectomy for patients with thymoma may be effective methods to improve not only prognosis but also MG, provided the range of resections are comparable to that of conventional open surgery.