術後血漿CEA値上昇により肺転移がチェックされた直腸早期癌（sm癌）の1例

A Case Report of Early Rectal Cancer: Its Lung Metastasis Was Diagnosed by Post-operative Elevation of CEA Titer

　1965年Goldの報告以来，血漿Carcinoembryonic Antigen（以下，CEA）が注目されているが，Goldが発表したように必ずしもCEAが大腸癌にspecificなものでなく，他の消化器癌のみならず，肺癌，乳癌にもみられ，また大腸の炎症性疾患にみられる半面，血漿CEA値が異常値を呈さない大腸癌も少なくないことがわかり，大腸癌の，特に早期癌のdetectionの検査方法としては必ずしも適切ではない．しかし，術前血漿CEA高値を示した大腸癌を切除すると，治癒切除では血漿CEA値は正常域にもどり，また術後の経過を追ってみると，再発を来たすとともに血漿CEAも高値になってくることが明らかであり，すなわち術後の再発のチェックには有意義な検査であるといえる．

　最近われわれの施設で小さなpolypoidの直腸癌を発見し，切除後いったん正常域にもどった血漿CEA値が数カ月後に異常な高値を示し，肺転移が発見され，再治療に成功した症例を経験したので報告をする．

　The patient was 65 year-old male who visited our clinic because of constipation and bloody stool. Rectal examination disclosed a polyp of type III by Yamada's classification, measuring 1.5×1.5 cm, at 8 cm from the anal verge. Polypectomy was performed and histological examination showed well differentiated adenocarcinorna invading down to the submuosa. In addition to the polypectomy, therefore, resection of the rectum was performed. Shortly after the polypectomy CEA titer was 240 ng/ml but it dropped down to 13.8 ng/ml after the resection of the rectum. During the post-operative follow-up, however, the CEA titer again jumped up to 305 ng/mi and repeated CEA titers were continued to be high. Therefore, extensive work-up for searching a metastatic lesion was carried out and abnormal shadow in the right upper lung field was found. It was felt lung metastasis and resection of the lesion was performed. Indeed, histologic examination showed lung metastasis of the rectal cancer and CEA titer fell down to 2.5ng/ml after the resection. Furthermore, the resected specimen was stained by fiuorsceinantibody method and it demonstrated the production of CEA in the tissue.