大腸ポリープの臨床的検討

1986年4月から1990年2月末までの間に岡山大学医学部附属病院三朝分院で経験した早期大腸癌を含む大腸ポリープ90例（107病変）を対象に，年齢，臨床症状，便潜血反応，病変存在部位について検討を行い，以下の成績を得た。(1)大腸検査総数の22.4％にポリープが発見された。ポリープの77％は腺腫，5％は腺癌（早期癌）であった。(2)便潜血反応はポリープ例の75.9％に陽性であり，右側大腸ポリープでの陽性率は高かったが，S状結腸および直腸ポリープでは70％程度であった。(3)若年者では右側結腸にポリープが発見されることは稀であるが，50才以上では18％程度に認められた。高齢者では右側結腸も内視鏡で検査することが重要である。(4)免疫学的便潜血検査法の導入により大腸ポリープの発見効率が改善するものと考え られた。

This report is concerned with clinical study on 90 patients with polypoid lesions (107 lesions) which we have encountered in Misasa Hospital, Okayama University in the past 4 years. Following results were obtained : (1) Polypoid lesions were detected in 90 (22.4%) and advanced adenocarcinoma (mostly resectable) in 22 (5.5%) of 402 patients who were examined by sigmoidoscopy and barium enema ; (2) Histological examination of the polypoid lesions showed adenoma in 77.2%, hyperplastic polyp in 8.7%, inflammatory polyp in 7.6%, neurinoma in 0.3% and early cancer (adenocarcinoma) in 5.4% ; (3) It was impossible to differentiate benign and malignant polypoid lesions on the basis of endoscopic and X-ray findings alone ; (4) Forty-two percent of the polypoid lesions was detected in the sigmoid colon, 30% in the rectum, 16.8% in the descending colon, 9.3% in the ascending colon, 0.9% in the caecum ; (4) Patients younger than 50 years of age showed only one polypoid lesion in the right hemicolon, whereas elder patients showed as many as 17 polypoid lesions ; (5) Among the 90 patients with polypoid lesions, 40 presented with abdominal pain, 20 with no symptoms (annual health check-up), 17 with irregular bowel habits, and 10 with melena ; (6) Among the 90 patients, occult blood in stool was positive in 75.8% with a lower positive rate in the lesions of the sigmoid and rectum ; (7) Among 5 asymptomatic patients with lesions and with a negative hemoccult test, 3 patients with a polypoid lesion were examined because of the patients' request, 1 patient with a polypoid lesion because of a positive family history, and the remaining 1 patient in a search for the primary lesion of the metastatic liver cancer ; (8) Among patients with a positive hemoccult test, the detection rate of polypoid lesions was 41.9% with use of an immunological method, whereas it was 19.7% with use of a chemical method. In conclusion, (1) detection of colonic polypoid lesions can lead to the detection of early cancer, although only histological examination can confirm the accurate diagnosis ; (2) a hemoccult test in stool with an immunological method is an effective method for screening asymptomatic colonic polypoid lesions, although it must be admitted that negative results may occasionally occur ; (3) macroscopic observation of the stool mass is important before sampling, because lesions of the sigmoid colon or the rectum may show scanty blood only on the limited area of the surface of the stool ; (4) patients elder than 50 years of age should be examined more carefully for the whole colon preferably with an endoscope, because they show a high incidence of small polypoid lesions in the right hemicolon.