Diagnosis of early cancer of the colon and rectum

When early cancer of the colon and rectum is defined as in early gastric cancer, i.e., invasion is limited to the mucosa and submucosa, 38 lesions from 35 patients of early cancer of the colon and rectum were detected during the last 20 years. The macroscopic and histologic findings included cancer-containing adenoma in 35 lesions from 32 patients. When the diagnostic methods were compared in 33 cases of early cancer of the colon and rectum, it was found that positive or suspicious cancer was obtained by an x-ray study in 5 of 18 cases examined (28%), by endoscopy in 19 of 31 cases (61%), by cytologic methods in 18 of 21 cases (86%), by biopsy in 19 of 25 cases (76%) and by polypectomy under direct vision through an endoscope in 13 of 14 cases (93%). When both biopsy and cytologic studies were performed in combination with endoscopy (20 cases), either of them was positive in all cases. These results indicate the possibility of correct diagnosis in many cases through the combined use of the cytologic method and biopsy without polypectomy, if the location is previously checked. On the other hand, 104 polyps from 90 patients were removed by means of the snare-electrocautery technique with the use of coagulation current during the last 4 years. The histologic findings revealed cancer-containing adenoma in 13, even in benign appearing polyps and in small polyps 1.0 cm or less in diameter. These results indicate that diagnosis of early cancer of the colon and rectum is difficult without polypectomy, if cancer is not previously suspected.