両側多発肺癌に対する外科治療戦略

Surgical Treatment to Bilateral Multiple Primary Lung Cancer Patients

検診の普及と治療法の進歩により高齢化がすすんだ現在，多発肺癌は増加傾向にある．多発肺癌とは同時性もしくは異時性に転移でなく複数個発生する原発性肺癌のことであり，原発性肺癌患者の約10～22％に存在するといわれている1，2）．しかし，多発肺癌は転移との診断がいまだに困難である．組織型は腺癌が多く，その発生にはEGFR遺伝子変異肺癌が多いことから，現在進歩が著しい化学療法と手術の適応にも変化がみられる3）．末梢発生の多発肺癌の外科的治療は，同側性肺癌であれば多くの場合，残存肺全摘除を除き手術が特に問題になることはないが，両側性多発肺癌の治療は予後と呼吸機能の観点からいまだ課題が多い．われわれは，当院での症例を対象として外科治療戦略を後方視野的に検討した．

Objectives：Multiple primary lung cancer （MPLC） has increased due to the extensive detection survey and patient’s life-prolonging, but the treatment strategy remains disputable. There is no consensus on the surgical treatment strategy, especially for bilateral multiple primary lung cancer （BMPLC） among MPLC. This paper aimed to discuss the surgical strategy in patients with bilateral multiple lung cancer by our experiences of surgical outcomes.

Methods：Patients who underwent curative operations for BMPLC based on the Martini-Melamed criterion and oncogene mutation analysis between January 2007 and May 2019 in Ishikawa Prefectural Central Hospital were reviewed retrospectively.

Results：We studied 53 patients （26 males and 27 females, from 64～84 years of age） with MPLC, 43 patients with metachronous lesions, and 10 patients with synchronous lesions. The type of resection for the first tumor was lobectomy 35 （66.0％） and segmentectomy or wedge, 18 （34.0％）, and for the second tumor was lobectomy 5 （9.4％） and segmentectomy or wedge, 17 （32.1％） respectively. Bilateral lobectomies underwent in four cases. Histologic classification was similar in 62.3％ of patients. Overall survival at five years after the second operation was 75.1％, respectively. There was no difference in subgroups of lobectomy and limited resection （wedge or segmentectomy）. Respiratory function in four patients performed with bilobectomy is enough before the second surgery （％vital capacity：84～136％, forced expiratory volume in one second：1,490～3,400 ml, DLco：82～151％）. There was no postoperative complication, but one patient suffered from low respiratory function and indications for oxygen therapy at 99 days after the second operation.

Conclusions：We selected the surgical procedures that preserve much lung tissues for BMPLC. Bilateral lobectomy did not usually perform in most cases. However, bilobectomy was no contraindication for BMPLC if a preoperative respiratory function was enough for the second tumor.