Colorectal cancer: the case for endoscopic screening

Clinical significance of diminutive polyps of the rectum and sigmoid colon

A retrospective review of 637 consecutive colonoscopies with polypectomy in 526 patients was performed to determine the association of small polyps of the rectum and sigmoid colon with more proximal colonic neoplasms. All colonic polyps were proximal to the sigmoid colon in 117 procedures. Proximal neoplasms were found in 32 percent of patients with a single polyp in the rectum or sigmoid colon. The incidence increased to 83 percent for those with three or more polyps. The occurrence of proximal colonic neoplasms was not affected by the size or histologic type of the rectosigmoid polyps. These findings would suggest that total colonic evaluation be considered in all patients with a polyp in the rectum or sigmoid colon regardless of the size or histologic type of the polyp.

Colorectal carcinoma: analysis of management in two medical eras

Trends in presentation, diagnosis, management, and outcome were analyzed for 503 patients with colorectal cancer seen at the UCLA Medical Center between 1960 and 1970 (Group A; n = 210) and 1980 and 1985 (Group B; n = 293). Patients in the latter group exhibited a shift in site to the right side of the colon (18% in Group A vs. 31% in Group B; P < .01), an increase in the number of primary resections without colostomy (38% vs. 61%; P < .01), a lower overall complication rate (28% vs. 18%; P = .01), and a decline in 30-day mortality (6.2% vs. 2%; P = .01). Although little difference was seen in detection of asymptomatic tumors, earlier lesions were treated in the latter group, accounting for substantially reduced rate of recurrence (69% in Group A vs. 44% in Group B; P < .01). Future management should include an emphasis on earlier detection in order to continue the trend toward enhanced survival.

Intraoperative colonoscopy in patients with colorectal cancer

Sixty-seven patients underwent intraoperative colonoscopy during elective surgery for colorectal cancer. Complete examination of the colon was achieved in 65 patients (97 per cent), albeit with insertion through a colotomy in three (4 per cent). A synchronous carcinoma was found in six patients (9 per cent), which necessitated a change of planned surgical procedure. Synchronous polyps were detected and removed in 24 patients (36 per cent); two had polyps with carcinoma in situ. The mean age of patients with synchronous carcinoma was significantly higher than that of those without (74.1 versus 61.2 years, P = 0.02). Intraoperative colonoscopy took a mean of 15 min surgical time and only two minor complications (serosal lacerations) were encountered. In patients with colorectal cancer, intraoperative colonoscopy allows complete assessment of the colon and identifies synchronous lesions.

Screening for large bowel neoplasms in individuals with a family history of colorectal cancer

Logistical problems associated with population screening for colorectal cancer are identified and the possibility of targeting screening to those with a familial predisposition to the disease is discussed. Evidence for a substantial genetic effect on the overall incidence of colorectal cancer is reviewed. The screening detection rate of colorectal neoplasms in relatives of patients with colorectal cancer has been shown to be higher than that expected in a non-selected population; the evidence that polypectomy will reduce future colorectal cancer risk in such individuals is explored. Recent advances in the molecular genetics of colorectal cancer susceptibility are reviewed; it is possible that a genetic test might be developed in the future which could identify at least a proportion of those at risk. Excluding financial considerations, the risk-benefit ratio of colonoscopy in a screened population is intimately related to the remaining risk of colorectal cancer in those who undergo the examination. At present, patients undergoing colonoscopy to investigate a positive faecal occult blood (FOB) test as part of a population-based screening programme include individuals with a familial predisposition as well as those without. About 20 per cent of all cases of colorectal cancer are associated with an obvious genetic predisposition, and the risk of cancer in their relatives is high. Because false positives occur with Haemoccult, the residual risk to the population who are FOB positive but do not have a familial trait may be sufficiently low that the dangers of colonoscopy could outweigh the potential benefits. Scotland has a high incidence of colorectal cancer, and analysis of recent Scottish incidence data shows an actuarial lifetime risk of developing this disease of one in 23 for men and one in 33 for women. As a family history of the disease increases that risk by two to four times and the neoplasms arise throughout the colon in such a group, there may be a case for offering colonoscopy to all first-degree relatives of those under 50 years of age at diagnosis, if not of all index cases of colorectal cancer.

Colonoscopic screening for neoplasms in asymptomatic first-degree relatives of colon cancer patients. A controlled, prospective study

Individuals with a family history of colorectal cancer are believed to be at an increased risk of developing colorectal neoplasia. To estimate this risk and the potential yield of screening colonoscopy in this population, we recruited and prospectively colonoscoped 181 asymptomatic first-degree relatives (FDR) of colorectal cancer patients and 83 asymptomatic controls (without a family history of colorectal cancer). The mean ages for the FDR and control groups were 48.2 +/- 12.5 and 54.8 +/- 11.0, respectively. Adenomatous polyps were detected in 14.4 percent of FDRs and 8.4 percent of controls. Although 92 percent of our FDRs had only one FDR afflicted with colon cancer, those subjects with two or more afflicted FDRs had an even higher risk of developing colonic adenomas (23.8 percent) than those with only one afflicted FDR (13.1 percent). A greater proportion of adenomas was found to be beyond the reach of flexible sigmoidoscopy in the FDR group than in the controls (48 percent vs. 25 percent, respectively). Logistic regression analysis revealed that age, male sex, and FDR status were independent risk factors for the presence of colonic adenomatous polyps (RR = 2.32, 2.86, and 3.49, respectively; P less than 0.001). Those at greatest risk for harboring an asymptomatic colonic adenoma are male FDRs over the age of 50 (40 percent vs. 20 percent for age-matched male controls). Based on probability curves, males with one FDR afflicted with colon cancer appear to have an increased risk of developing a colonic adenoma beginning at 40 years of age. Our results document, for the first time, an increased prevalence of colonoscopically detectable adenomas in asymptomatic first-degree relatives of colon cancer patients, as compared with asymptomatic controls, and support the use of colonoscopy as a routine screening tool in this high-risk group.

Presentation, duration of symptoms and staging of colorectal carcinoma

A prospectively recorded, consecutive series of 155 colorectal carcinoma specimens clinically and pathologically staged according to the Australian Clinico-pathological System (ACPS) between April 1987 and May 1989 at Wellington and Kenepuru Hospitals is reviewed. Clinical records were available for retrospective review for 146 of the 155 patients. Change in bowel habit, rectal bleeding and abdominal pain were the most common presenting symptoms. Thirty-five patients presented as emergencies, twenty-six with obstruction and nine with perforation. Abdominal pain resulted in the earliest surgical intervention. The median duration of symptoms prior to diagnosis was 3 months. No correlation existed between tumour stage and duration of symptoms. Earlier diagnosis during the symptomatic phase of colorectal carcinoma is unlikely to contribute significantly to improved overall survival.

Metachronous colorectal carcinoma

During the period 1943-67, 903 Danish patients aged less than 40 years had colorectal carcinoma. The patients were followed up for up to 41 years and during this period 44 of 501 (9 per cent) operated on for cure developed a metachronous colorectal carcinoma. The cumulative risk of a metachronous colorectal carcinoma was 30 per cent after up to 41 years of observation. The occurrence of a metachronous colorectal carcinoma was evenly distributed in the observation period. The cumulative survival rate after operation for a metachronous colorectal carcinoma was 41 per cent after 20 years of observation. We propose a lifelong follow-up programme after resection of colorectal carcinoma for cure in this age group, including annual Hemoccult test and colonoscopy at 3-year intervals.

Update on colorectal cancer. Risk factors, diagnosis, and treatment

Colorectal cancer is more common in the Western world than in underdeveloped countries. Diet, longevity, heredity, and presence of other bowel diseases may affect the incidence. Diagnosis is based on results of routine laboratory studies and evaluation of the entire large bowel with air-contrast barium enema and colonoscopy. Surgical resection is the primary therapy for colorectal cancer. Postoperative systemic chemotherapy yields poor results, but hepatic artery infusional chemotherapy offers some benefit to patients who have only hepatic metastases. Follow-up evaluation includes physical examination and laboratory studies every 3 months for the first 2 years and colonoscopy every year.

Role of sigmoidoscopy in screening for colorectal cancer: a critical review

The use of sigmoidoscopy as a screening method for colorectal cancer is controversial. Evidence regarding its efficacy is reviewed critically, with special attention given to potential biases in screening studies. The vast majority of studies are uncontrolled and without follow-up information and thus shed little light on the actual benefits of sigmoidoscopy. Two uncontrolled studies with follow-up and one randomized trial suggest a colorectal cancer mortality reduction because of the use of sigmoidoscopy, but all three studies have major shortcomings. The authors conclude that the currently available data are insufficient to establish a national recommendation for screening with sigmoidoscopy. To establish such a recommendation, a properly conducted randomized trial with colorectal cancer mortality as an outcome is needed.

Improvements in the treatment and prognosis of colorectal carcinoma

In a survey of the surgical results in 709 patients with colorectal carcinoma (CRC) treated between 1976 and 1985 a favourable shift of stage distribution was observed. The tumour was localized (Dukes' classification A or B) in 61 per cent of patients, as compared with 47 per cent in the previous 10-year period. This change was, in part, due to different interpretation of stage definitions. Clear improvements of the results were, however, also noted. Radical surgery was possible in 76 per cent of patients and the primary tumour was removed in 93 per cent. Surgical mortality was 4.4 per cent and complication rate 15 per cent, significantly less than earlier (6.5 and 38 per cent, respectively). Increasing numbers of sphincter-saving operations were performed in rectal cancers (47 per cent as compared with 24 per cent in the previous 10-year period). The overall 5-year survival rate improved from 40.5 to 52.5 per cent. Premalignant conditions were identified in 12.6 per cent of patients: previous CRC 4.8 per cent, cancer family syndrome 4.1 per cent, ulcerative colitis 1.7 per cent and familial adenomatosis 0.6 per cent. In order to sustain the favourable trend of improving survival prospects, more emphasis must be directed to the detection of early stage cancers.