| 特集名 | リンチ症候群と遺伝性消化管ポリポーシス | |
|---|---|---|
| 題名 | 総論 (2) 癌の遺伝カウンセリング | |
| 発刊年月 | 2019年 06月 | |
| 著者 | 新井 正美 | 順天堂大学大学院医学研究科難治性疾患診断・治療学 |
| 【 要旨 】 | 遺伝性腫瘍では，個々の癌には治療法や検診，リスク低減手術などの対策がある場合が多く，現在では遺伝学的検査を積極的に日常診療に活用する傾向にある．代表的な遺伝性腫瘍であるリンチ症候群では，臨床情報から疑い症例を拾い上げて，MSI検査等のスクリーニング検査を実施して，最終的に遺伝学的検査を実施する．このプロセスは従来の古典的な癌の遺伝カウンセリングのなかで行われる． 一方で，PD‒1抗体薬のコンパニオン診断（companion diagnostics；CDx）としてMSI検査が診療科で実施され，さらに癌ゲノム医療が始まるなかで，本来の目的ではないが，二次的にリンチ症候群と診断されることが起こりうる．このような状況から引き継いで行う新しいタイプの癌の遺伝カウンセリングでは，遺伝性腫瘍の可能性を指摘された進行再発癌患者が受診する．これらの検査では，遺伝性腫瘍が診断される場合があることを事前に説明して，もし変異が見つかった場合の対応についてあらかじめ検討しておくことが重要である．さらに新しいタイプの癌の遺伝カウンセリングでは，本人の治療だけではなく，その遺伝情報を血縁者で共有し彼らの健康管理に繫げる配慮も重要である． |
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| Theme | Lynch Syndrome and Hereditary Polyposis Syndromes | |
|---|---|---|
| Title | Genetic Counseling for Cancer | |
| Author | Masami Arai | Diagnostics and Therapeutics of Intractable Diseases, Juntendo University, Graduate School of Medicine |
| [ Summary ] | Providing appropriate information and psychosocial support is essential to carry out genetic counseling for hereditary cancer syndromes. There are effective therapies or preventive procedures (e. g. risk reducing salpingo‒oophorectomy in BRCA1/2 mutation carriers) available for many hereditary cancer syndromes, and genetic information of patients with hereditary cancer syndrome can to be effectively utilized in clinical practice, as early detection and treatment can lead to increased survival. Lynch syndrome, which is a representative hereditary cancer syndrome, is at first screened based on clinical information and microsatellite instability (MSI) testing, and finally diagnosed by genetic testing. This process is performed in classical genetic counseling. Recently, another aspect of genetic testing has emerged, leading to a new type of genetic counseling. MSI testing is currently also being performed as a companion diagnostic (CDx) for anti PD‒1 drugs treatment in clinical divisions in addition to screening for Lynch syndrome and cancer panel testing for choice of molecular target‒based drugs will be used shortly in Japan. As a result, Lynch syndrome could be secondarily diagnosed through CDx or cancer panel testing. In such cases, clinicians will be required to inform patients about the possible secondary diagnosis of hereditary cancer syndromes beforehand in order to prepare them for such an eventuality. New type of genetic counseling for cancer should, therefore, not only focus on the proband's treatment, but also on sharing the proband's genetic information with her or his relatives to improve their healthcare, although many probands suffer from metastatic or recurrent cancers. |
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