早期非小細胞肺癌における区域切除後断端再発

Analysis of Surgical Margin Recurrence Following Segmentectomy for Early-stage Non-small Cell Lung Cancer

診断技術の進歩や検診の普及により非小細胞肺癌が早期に発見される頻度が増えたが，非小細胞肺癌の標準術式は肺葉切除とされ，小型肺癌に対しても肺葉切除が行われることが多かった．日本臨床腫瘍研究グループ（JCOG）0802試験の結果が報告され，腫瘍径2 cm以下・充実成分径/腫瘍径比＞0.5の臨床病期ⅠA期肺野型非小細胞肺癌患者に対する区域切除の優越性が証明された1）．しかし，肺葉切除より区域切除で局所再発率が2倍程度高かった．区域切除後の切除断端再発は肺葉切除を行っていれば回避できた可能性が高いため，断端再発は区域切除後の特に留意すべき再発形式である．

Background：Surgical margin recurrence following segmentectomy is a critical issue because it may have been avoided by lobectomy.

Methods：Between January 2000 and December 2018, we retrospectively investigated 199 patients who underwent segmentectomy for c-StageⅠ non-small cell lung cancer at our hospital.

Results：Recurrence occurred in 20 cases, of which 3 cases had surgical margin recurrence. In our previous study, the recurrence risk factor after segmentectomy was radiologic solid tumor size （cut-off value 1.5 cm）. Of the 130 patients in the low-risk group with radiologic solid tumor size of less than 1.5 cm, five had any recurrence, three of which had surgical margin recurrence. In the high-risk group with radiologic solid tumor size of 1.5 cm or more, no surgical margin recurrence was observed. Three cases of surgical margin recurrence were accompanied by lepidic components, and the tumors were difficult to identify intraoperatively and were located close to adjacent areas.

Conclusion：Surgical margin recurrence may be avoided by carefully considering the segments to be resected and improving the method for identifying the intersegmental plane.