食道表在癌リンパ節転移診断―EUSの立場から

Diagnosis of Metastatic Lymph Nodes of Esophageal Superficial Cancer―From the Standpoint of Endoscopic Ultrasonography

要旨　食道表在癌の縮小治療を考えるとき，正確なリンパ節転移診断は必要不可欠である．EUSは精度の高い検査法として認知されている．その有効性は，リンパ節の描出能の高さでも証明できる．術前診断転移リンパ節個数と郭清転移リンパ節個数の比を，予測係数として信頼度を検討すると，EUSは1.003でCTの0.31と比べ良好な描出能を示した．EUSはCTに比べより多くの転移陽性リンパ節を診断でき，それぞれの部位で多く読む傾向にある．偽陰性が少ないことは，食道表在癌の縮小治療に対し有効な検査法であると言えるが，より精度を高めるためには他の画像診断と合わせ総合的に診断することが望ましい．しかし，術前に完全なリンパ節転移診断をすることは不可能であるから，SM癌の縮小治療には慎重にならざるを得ないと思われる．

　It is vital for exact diagnosis of lymph node metastasis when we are considering minimum invasive treatment for esophageal superficial cancer. EUS (endoscopic ultrasonography) is recognized as a precision examination method. We can prove the validity of EUS because it can accurately detect lymph nodes.

　When we set the predicted coefficient of lymph node metastasis, that is the ratio of the number of detected lymph nodes to the pathological result, EUS is 1.003 and enhanced CT is 0.31, so EUS has a better ability of expression than enhanced CT. EUS can detect more metastatic lymph nodes than are detected with CT, and it has a tendency to find too much.

　It means that EUS is an effective examination previous to minimum invasive treatment of esophageal superficial cancer, because few false negative nodes are detected by it. On the other hand, to diagnose lymph node metastasis using other radiological imaging techniques raises diagnostic precision.

　But it is impossible to carry out this diagnose completely before the operation, we must handle the minimum invasive treatment of submucosal cancer carefully.