画像診断による化学療法の原発巣の効果判定―大腸癌─内視鏡検査および総合評価

Endoscopic Evaluation of Primary Tumor in Metastatic Colorectal Cancer Patients who Received Chemotherapy

要旨　一般的に化学療法の治療効果判定にはRECISTが用いられ，内視鏡の有用性は明確ではない．原発巣を切除せずに化学療法を先行した切除不能進行大腸癌症例を対象に，内視鏡による原発巣における化学療法効果判定の意義を検討した．今回の31例の検討ではRECISTの総合効果がPR，SD時には原発巣の内視鏡所見が増悪したものはなく，定期的な内視鏡検査は必要ないことが示唆された．一方，RECISTの総合効果がPD時，特にCTにて原発巣による腸管の通過障害が疑われた場合は腸管狭窄を来す可能性が高くなることから内視鏡での評価が望ましいと考えられた．今後はCTの弱点を内視鏡でいかに補うかについての検討が必要と考える．

　To assess the response to chemotherapy of metastatic colorectal cancer, the usefulness of endoscopy is uncertain and RECIST is generally used. Endoscopic evaluation was carried out in patients who received chemotherapy without prophylactic surgery for primary tumor. For most patients with PR or SD in RECIST, the primary tumor was not progressive. Therefore, periodic endoscopic examination may not be necessary when the disease is stable according to RECIST. However, for patients with PD in RECIST, or when intestinal stenosis has been pointed out by CT, the incidence of intestinal stenosis is rather high. Therefore endoscopic examination may be necessary to evaluate the extent of stenosis in such situations. Further investigation is needed to show how endoscopic evaluation can compensate for the weak points of CT.