免疫チェックポイント阻害薬関連消化管病変

Gastrointestinal Toxicity of Immune Checkpoint Inhibitor

要旨●免疫チェックポイント阻害薬は，既存の悪性腫瘍治療薬と異なる作用機序を持つ，新規抗悪性腫瘍薬である．しかし，免疫関連有害事象という既存治療薬では認めなかった有害事象を生じうる可能性がある．その一つに大腸炎があり，下痢，腹痛，血便などの症状を呈する．診断は除外診断が必要となるが，内視鏡検査が有用である．CTCAE Grade 2以上の重症度の際は，ステロイドを用いた治療が必要となる．ステロイド抵抗性の際はインフリキシマブを用いることが各種ガイドラインで推奨されている．免疫関連有害事象に対しては，がん治療主治医のみでなく，多診療科医師・コメディカルなど病院全体での対策・連携が重要である．

　Immune checkpoint inhibitors are novel anti-cancer drugs with mechanisms that are different from conventional anti-cancer drugs. Unfortunately, they are associated with characteristic adverse events, termed irAE（immune-related adverse events）, including colitis, pneumonitis, skin rash, interstitial nephritis, and thyroiditis. Colonoscopy is useful for the diagnosis of colitis, which presents with symptoms such as diarrhea, abdominal pain, and bloody stool, and it requires the exclusion of other diseases with similar symptoms. Guidelines recommend steroid therapy for grade ≧2 colitis according to the Common Terminology Criteria for Adverse Events. Furthermore, infliximab therapy is recommended for steroid-resistant colitis. Collaboration among oncologists, gastroenterologists, and other clinicians and medical staff is important for proper management of irAE in patients treated with immune checkpoint inhibitors.