Repeat colonoscopy after endoscopic polypectomy

Recurrence and malignancy rates in a benign colorectal neoplasm patient cohort: results of a 5-year analysis in a managed care environment

OBJECTIVE

To estimate the apparent recurrence rates of benign neoplasms and the development of malignant colorectal neoplasms over a 5-yr period in a high risk managed care population.

METHODS

Using the CPT and ICD-9 CM codes, a cohort of subjects with benign neoplasms were identified with a colonoscopy in 1992 from a longitudinal claims database (MarketScan). Three groups of subjects (benign neoplasms with polypectomy, benign neoplasms without polypectomy, and no neoplasms) were evaluated. Five-year recurrence rates of benign or new malignant colorectal neoplasms were determined for the baseline benign neoplasms with polypectomy and no neoplasm groups. For the benign neoplasm without polypectomy, only rates for malignancy were evaluated.

RESULTS

Of 16,293 subjects at baseline, 39.50% were diagnosed with benign and 5.50% with malignant neoplasms. The 5-yr cumulative incidence of benign neoplasms in subjects without an index neoplasm (n = 8,967) was 7.92% compared to the recurrence of 40.93% in subjects with a benign neoplasm and polypectomy (n = 4,046) at baseline (p < 0.001). The 5-yr cumulative incidence rates of malignant colorectal neoplasms in the no neoplasm (n = 8,967) and benign neoplasm groups (n = 6,438) were 1.81% and 2.55%, respectively (p < 0.005). A lower 5-yr malignancy rate was observed in benign neoplasm group with polypectomy (2.17%) compared to the benign neoplasm group without polypectomy (3.18%) (p < 0.05).

CONCLUSION

The high recurrence rate of benign colorectal neoplasms and a higher incidence of colorectal cancer in subjects at high risk (history of benign colorectal neoplasm) highlight a healthcare opportunity for surveillance and/or interventions to reduce the morbidity associated with colorectal neoplasms.

Growth of colorectal polyps: redetection and evaluation of unresected polyps for a period of three years

BACKGROUND, AIMS, AND PATIENTS: In a prospective follow up and intervention study of colorectal polyps, leaving all polyps less than 10 mm in situ for three years, analysis of redetection rate, growth, and new polyp formation was carried out in 116 patients undergoing annual colonoscopy. The findings in relation to growth and new polyp formation were applied to 58 subjects who received placebo.

RESULTS

Redetection rate varied from 75-90% for each year, and was highest in the rectum and sigmoid colon. There was no net change in size of all polyps in the placebo group, however, polyps less than 5 mm showed a tendency to net growth, and polyps 5-9 mm a tendency to net regression in size, both for adenomas and hyperplastic polyps. This pattern was verified by computerised image analysis. Patients between 50 and 60 years showed evidence of adenoma size increase compared with the older patients, and the same was true for those with multiple adenomas (four to five) compared with those with a single adenoma. The new adenomas were significantly smaller and 71% were located in the right side of the colon. Patients with multiple adenomas had more new polyps at all the follow up examinations than patients with a single adenoma. One patient developed an invasive colorectal carcinoma, which may be evolved from a previously overlooked polyp. Two polyps, showing intramucosal carcinoma after follow up for three years, were completely removed, as judged by endoscopy and histological examination.

CONCLUSIONS

The results show that follow up of unresected colorectal polyps up to 9 mm is safe. The consistency of growth retardation of medium sized polyps suggests extended intervals between the endoscopic follow up examinations, but the increased number of new polyps in the proximal colon indicates total colonoscopy as the examination of choice. The growth retardation of the medium sized polyps may partly explain the discrepancy between the prevalence of polyps and the incidence of colorectal cancer.

Surveillance of colorectal cancer: effectiveness of early detection of intraluminal recurrences on prognosis and survival of patients treated for cure

PURPOSE

The authors evaluate the effectiveness of routine colonoscopy and marker evaluation in diagnosis of intraluminal recurrent cancer.

METHODS

Chart review was conducted on 481 patients who underwent curative resection for colorectal cancer between 1980 and 1990. Clinical visits were scheduled and carcinoembryonic antigen evaluation was performed every three months, and colonoscopy was performed preoperatively, 12 to 15 months after surgical treatment, and then with intervals of 12 to 24 months or when symptoms appeared.

RESULTS

About 10 percent of patients developed intraluminal recurrences. More than one-half of metachronous lesions arose within the first 24 months, and median time to diagnosis was 25 months. Patients with left-sited tumors in the advanced stage had a higher risk of developing recurrent intraluminal disease. Twenty-nine patients underwent a second surgical operation, of which 17 cases were radical. In this group, the five-year survival was 70.6 percent, although no nonradically treated or nonresected patients survived longer than 31 months. Twenty-two patients were asymptomatic at time of diagnosis of recurrence, and of these, 12 patients underwent radical operation; on the other hand, of the 24 symptomatic patients, only 5 were treated radically. Carcinoembryonic antigen was the first sign of recurrence in eight cases. Colonoscopy must be performed within the first 12 to 15 months after operation, whereas an interval of 24 months between examinations seems sufficient to guarantee early detection of metachronous lesions.

CONCLUSION

Serial tumor marker evaluation is of help in earlier diagnosis of local recurrences. Asymptomatic patients more frequently undergo another operation for cure and thus have a better survival rate.

Growth of colorectal polyps: recovery and evaluation of unresected polyps of less than 10 mm, 1 year after detection

BACKGROUND AND METHODS

Colonoscopic 1-year control of polyps of less than 10 mm left in situ was carried out in 103 (89%) of 116 originally examined patients.

RESULTS

Analysis showed an 85% recovery: 91% and 81% for polyps of 5-9 mm and < 5 mm, respectively. The recovery was significantly related to size and localization, whereas the growth rate was inversely correlated to the originally measured diameter. A linear relationship was demonstrated between anus-to-polyp distances 1 year apart, with a normalized agreement index of 0.70. In only 1 of 189 polyps, an increase of diameter to > 10 mm was demonstrated. The 79 new polyps in 52 (50%) of the patients were significantly smaller, more often right-sided, and related to multiplicity of polyps at the initial examination but not to growth of recovered polyps or cleansing status.

CONCLUSION

An acceptable recovery and growth rate of polyps < 10 mm seems to justify the continuation of the study for the remaining 2 years.

Antioxidant vitamins or lactulose for the prevention of the recurrence of colorectal adenomas. Colorectal Cancer Study Group of the University of Modena and the Health Care District 16

Colonic adenomas represent the natural precursor lesions of most colorectal cancers. The treatment of choice is endoscopic polypectomy. However, after endoscopic removal, polyps recur in a large fraction of cases. Thus, we evaluated the effect of antioxidant vitamins or lactulose on the recurrence rate of adenomatous polyps. After polypectomy, 255 individuals were randomized into three groups. Group 1 was given vitamin A (30,000 IU/day), vitamin C (1 g/day), and vitamin E (70 mg/day); Group 2 was given lactulose (20 g/day); Group 3 received no treatment. Forty-six subjects had to be excluded because the histologic diagnosis was not consistent with adenoma. The remaining 209 individuals were included in the analysis according to the "intention to treat" criterion, though 34 did not adhere to the scheduled treatment or were lost during the follow-up. Subjects were followed at regular intervals for an average of 18 months. Polyps recurring before one year from index colonoscopy were considered missed by the endoscopist. In the 209 evaluable subjects, the percentages of recurrence of adenomas were 5.7 percent, 14.7 percent, and 35.9 percent in the vitamins, lactulose, and untreated groups, respectively. The fraction of subjects remaining free of adenomas, estimated by Kaplan-Meier survival curves, was significantly different among the three groups (log-rank chi-squared = 17.138; P < 0.001). Using Cox's regression analysis, treatment was the only variable that significantly contributed to the model (regression coefficient = 0.905; P < 0.001). In conclusion, either antioxidant vitamins or, to a lesser extent, lactulose lower the recurrence rate of adenomas of the large bowel and can be proposed as chemopreventive agents, at least in high-risk individuals.

Reliability of in situ measurements of colorectal polyps

A reliable and sensitive in situ method for measuring polyp size is fundamental for growth studies of colonic polyps. A measuring probe inserted through a colonoscope can give a visual assessment of polyp diameter, and from a picture of the polyp the area of the polyp on the picture can be calculated by computerized analysis. To test the reliability and sensitivity of these two in situ measurements, 43 colonic polyps (mean diameter, 8.5 mm; range, 4-20 mm) removed by snare diathermy resection were examined. The maximal diameter was measured, and two Polaroid pictures taken of each polyp. After polypectomy each polyp was subjected to extracorporeal reassessment of diameter and measurement of weight and volume. By computerized analysis of the pictures the following variables were estimated: 1) area of the polyp on the picture; 2) largest diameter; 3) maximum width 90 degrees on the largest diameter; 4) maximum distance from centre of gravity; and 5) minimum distance from centre of gravity. Results showed good correlation between diameter measured in situ and after removal (r = 0.93), diameter raised to the 3rd power and weight (r = 0.93), and also to volume (r = 0.77). Area analysis compared with weight was less good (r = 0.72). A very high correlation was demonstrated between weight and volume (r = 0.99). We conclude that the measurement of diameter in situ with a measuring probe is sensitive and somewhat more reliable than computerized analysis of size. The present 3-year follow-up and intervention study will show which of the two methods is preferable for evaluation of polyp growth.

Usefulness of performing colonoscopy one year after endoscopic polypectomy

This retrospective study defines a population with neoplastic colonic polyps who have had colonoscopic polypectomy and, in follow-up within one year, a repeat colonoscopic evaluation. The population was broken down into two groups, one group that had polyps at the second examination and one group that did not. This study determined which factor(s) were significant among this population in distinguishing whether new polyps would be found at one year follow-up. The authors found that among the many variables studied, only polyp multiplicity was significant in predicting polyp recurrence. More than one polyp found at index colonoscopy led to a significant chance of having a new polyp after only one year. Also, it was demonstrated that these "new" polyps were unlikely to have been "missed" polyps from the initial colonoscopy. Because of the shifting location, smaller size, and fewer instances of histologic atypia in these polyps compared with those at index examination, the authors believe that polyps found after one year may be assumed to have arisen de novo. Finally, the authors show that a significant number of polyps occur beyond the reach of the flexible sigmoidoscope (approximately 60 cm). The authors recommend that patients who have polyps undergo a colonoscopic examination. When patients are re-evaluated after having colonoscopic neoplastic polypectomy, they should undergo repeat colonoscopy.

Endoscopic screening and surveillance for gastrointestinal malignancy

In the US, the cumulative lifetime risk of developing carcinoma of the upper gastrointestinal tract is less than 1 per cent, premalignant conditions are uncommon, and esophageal and gastric malignancies are rarely curable even when identified early. Endoscopic screening of the upper gastrointestinal tract in asymptomatic persons thus cannot be justified. Surveillance of persons with certain uncommon conditions associated with a higher risk of upper gastrointestinal cancer may be of benefit. These conditions include achalasia, Barrett's esophagus, chronic atrophic gastritis with intestinal metaplasia, familial polyposis coli, gastric polyps, lye stricture, Plummer-Vinson syndrome, and tylosis. In the lower gastrointestinal tract, however, the lifetime risk of developing carcinoma is 5 per cent, premalignant conditions and lesions are common, and carcinoma is curable when detected at an early stage. Sigmoidoscopic screening of asymptomatic adults has been advocated by the American Cancer Society but has not become widely practiced because of its cost, required physician effort, low overall yield, and poor patient compliance. Surveillance by flexible sigmoidoscopy is recommended for persons at slightly increased risk of colorectal carcinoma who have prior breast or gynecologic malignancy or a family history of colorectal malignancy. Colonoscopic surveillance is recommended for patients with high risk of colorectal cancer who have had prior colorectal carcinoma or adenoma or who have inflammatory bowel disease or a ureterosigmoidostomy.