肺癌縮小手術の現状

Current Status of Limited Resection for Lung Cancer as Minimally Invasive Surgery

近年，画像診断技術の急速な進歩や肺癌に対する一般的な意識の高まり，あるいはCT検診などの普及により，早い段階での肺癌外科治療として縮小手術の意義は以前よりも非常に高くなってきている．肺癌低侵襲手術には，①肺切除範囲の縮小，②リンパ節郭清範囲の縮小，③胸腔アプローチの低侵襲化が考えられる．臨床においては，腫瘍学的側面と身体的側面を考慮したうえでもっとも適切な術式が決定されるが，選択された術式の侵襲性は上記3因子の組み合わせによって決まる．本稿では肺癌に対する縮小手術の現状について，これまでの報告をもとに概説し，当院での手術成績を後方視的に検討した．

This review article describes limited resection for lung cancer based on previous reports and a retrospective examination of the operative results at our hospital. The importance of limited resection as a surgical treatment is becoming much greater than before. In minimally invasive surgery for lung cancer, ①limited resection for pulmonary functional preservation, ②limited resection of lymph node dissection, and ③minimally invasive thoracic approach may be considered. Radical segmentectomy was limited to the cases registered in the clinical trials ［the Japan Clinical Oncology Group （JCOG） study 0802/1211］to verify the validity of limited surgery. The patients who would not tolerate lobectomy underwent passive sublobar resection. Selective lymph node dissection （SLND） is commonly performed in daily clinical practice in Japan, although there is no scientific verification proven by prospective study clinical trials. Since 2013, the indication for selective lymph node dissection in our hospital has been a clinico-surgical N0 cases with a tumor diameter of 5 cm or less, excluding the right middle lobe, left lingular segment, and S6 primary tumor. Rapid intraoperative diagnosis of lymph node metastases is indispensable. Limited resection involves less surgical invasion in terms of operative duration and blood loss volume than a standard procedure, with fewer postoperative complications. In the future, the results of randomized controlled trials （RCTs） originated in Japan is expected to determine whether segmentectomy and SLND are valid and practical enough to become standard procedures of surgical treatment for early-staged patients. In limited resection for lung cancer, it is important to evaluate lymph node, not only preoperatively but also intraoperatively making appropriate diagnoses.