LA CONSULTA SEMANAL

JULIO 2000

CONSULTA

Am J Gastroenterol 2000 May;95(5):1147-51

Approach to colon polyps in the elderly.

Miller KM, Waye JD

Department of Gastroenterology, Mount Sinai Hospital, New York, New York, USA.

Colorectal cancer is a common but potentially preventable disease. Nearly all colorectal cancers are thought to arise from adenomatous polyps. The conclusions from the National Polyp Study strongly support the concept that the removal of polyps may prevent the future development of colorectal cancer. With the growing acceptance of screening for colorectal cancer, many elderly patients with adenomatous polyps will be discovered. Because increasing age is a powerful determinant of a higher prevalence of colonic neoplasia in asymptomatic individuals, physicians will need to be prepared to make informed decisions regarding the treatment of elderly patients with colonic polyps. The literature is reviewed and guidelines are formed regarding the optimal surveillance interval for patients with colonic polyps. The age at which surveillance and screening for colorectal neoplasia should stop is also reviewed. Conclusions are
based on the currently available data.

Publication Types:

Review

Review, tutorial

Endoscopy 2000 Feb;32(2):124-30

Colon polyps and cancer.

Kronborg O

Odense University Hospital, Denmark.

Several important studies on screening for colorectal neoplasia were published in 1998-99, including average-risk as well as high-risk groups, and different strategies such as endoscopy, fecal occult blood tests, and other more specific markers of neoplasia. Some of these studies included the use of interventions other than initial screening and polypectomy; a few dealt with diagnostic methods in symptomatic patients, and the new diagnostic tool of virtual colonoscopy was highlighted by several authors. Endoscopic treatment for large adenomas and early colorectal cancer has become more widespread, but clearly it has limitations. Current discussion of the topic of colorectal polyps and cancer is largely based on the concept of the adenoma-carcinoma sequence, which is thought to be the most probable pathogenesis for colorectal cancer.

Publication Types:

Review

Review literature

N Engl J Med 2000 Jun 29;342(26):1960-8

Chemoprevention of colorectal cancer.

Janne PA, Mayer RJ

Department of Adult Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.

Publication Types:

Review

Review, tutorial

Lancet. 1999 Nov 27;354(9193):1873-4. [Texto completo]

Colorectal hyperplastic polyps and risk of recurrence of adenomas and hyperplastic polyps.(Statistical Data Included)

Steven P Bensen, Bernard F Cole, Leila A Mott, John A Baron, Robert S Sandler, Robert Haile, for the Polyps Prevention Study Group

J Am Coll Surg 1999 May;188(5):503-7

Hyperplastic-adenomatous polyposis syndrome.

Place RJ, Simmang CL

Department of Surgery, University of Texas Southwestern Medical Center, Dallas 75235-9156, USA.

BACKGROUND: Although the syndrome of familial adenomatous polyposis is well known, sporadic patients with multiple polyposis are rare. There are no known syndromes associated with hyperplastic polyposis. In our search of the English surgical literature, we find no reference to a hyperplastic-adenomatous polyposis syndrome. STUDY DESIGN: Over a 3-year period, we identified six patients ages 41 to 75 (mean age 61) with 50 to 100 hyperplastic polyps associated with adenomas. RESULTS: Most of the hyperplastic polyps were found in the left colon and the largest ranged in size from 6 mm to 18 mm. The larger polyps were clinically indistinguishable from adenomas. Three of our six
patients had invasive cancer of the proximal colon. All tumors were confined to the bowel wall. There was a family history of colon cancer in only one patient and no family history of polyposis. CONCLUSION: These patients differ from previously described patients with polyposis syndromes; hyperplastic-adenomatous polyposis syndrome (HAPS) occurs in an older population with no family history of polyposis, has fewer polyps, most of which are hyperplastic, and is strongly associated with adenocarcinoma of the colon. In this series, we describe a previously unreported hyperplastic - adenomatous polyposis syndrome.

Publication Types:

Review

Review of reported cases

Am J Med 1999 Jan 25;106(1A):38S-42S

Wheat bran fiber and development of adenomatous polyps: evidence from randomized, controlled clinical trials.

Macrae F

Department of Gastroenterology, Royal Melbourne Hospital, Victoria, Australia.

Mutations in oncogenes and tumor suppressor genes are thought to initiate and promote the pathway to colorectal cancer, leading to hyperproliferation, the development of adenomas, and progression to gross malignancy. Intervention at any of these steps can potentially prevent the development of cancer. Several
randomized, controlled trials have investigated the effect of dietary interventions, including the addition of wheat bran fiber, on the development of adenomatous polyps. In a familial adenomatous polyposis trial, patients were treated with 4 g of ascorbic acid plus 400 mg of alpha-tocopherol per day alone or with a grain fiber supplement (22.5 g/day) over a 4-year period. On an actual-intake basis, the combined intervention inhibited the development of rectal polyps. However, the Toronto Polyp Prevention Trial found no significant differences in polyp recurrence rates between patients who were counseled to follow a low-fat, high-fiber diet and patients consuming a typical Western diet with placebo fiber. A 9-month study of patients with resected colon adenomas found that dietary wheat bran fiber significantly reduced total, primary, and secondary fecal bile acid concentrations and excretion rates. Such bile acid levels are thought to be related to the risk of developing cancer. The Australian Polyp Prevention Project reported that the combination of fat reduction and a supplement of wheat bran reduced the incidence of large colorectal adenomas. These latter results suggest that intervention with a low-fat wheat bran supplemented diet inhibits the transition from smaller to larger adenomas, which may be a critical step in determining which adenomas progress to malignancy.

Publication Types:

Review

Review, tutorial

Endoscopy 1999 Jan;31(1):60-5

Colon polyps and cancer.

Bond JH

Gastroenterology Section, Minneapolis Veterans' Association Medical Center and University of Minnesota, 55417, USA.

A number of recent publications dealing with colon polyps and cancer emphasize cost-effectiveness and the outcomes of screening and follow-up surveillance of high-risk groups. These groups include patients with either a past personal history or a family history of colorectal adenomas or cancer. Several papers address the effectiveness and compliance with different methods of screening of the asymptomatic, average-risk population for colorectal neoplasia. Other important publications deal with colorectal cancer prevention, the natural history of the adenoma-carcinoma sequence, diagnosis of polyps and cancer, colonoscopic polypectomy, management of the patient with a malignant polyp, and endoscopic treatment of obstructing cancer.

Publication Types:

Review

Review, tutorial

Am J Gastroenterol 1998 Apr;93(4):619-22

Colonic polyps: experience of 236 Indian children.

Poddar U, Thapa BR, Vaiphei K, Singh K

Department of Gastroenterology and Pathology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.

OBJECTIVES: We studied the clinical spectrum, histology, and malignant potential of colonic polyps in Indian children (< or =12 yr). METHODS: Two hundred thirty-six children with colonic polyps were studied from January 1991 to October 1996. They were evaluated clinically and colonoscopic polypectomy was done. Children with five or more juvenile polyps were labeled as having juvenile polyposis and serial colonoscopic polypectomies were done every 3 wk. Colectomy was performed when there were intractable symptoms or clearing of the polyps by colonoscopy was not possible. Histological examination of the polyps was done. Follow-up colonoscopy was done in children with juvenile polyposis only. RESULTS: The mean age of these children was 6.12 +/- 2.7 yr, with a male preponderance (3.5:1). Rectal bleeding of a mean duration of 14 +/- 16 months was the presenting symptom in 98.7%. Solitary polyps were seen in 76%, multiple polyps in 16.5%, and juvenile polyposis in 7% (n = 17) of the children. A majority (93%) of the polyps were juvenile and 85% were rectosigmoid in location. Adenomatous changes, seen in 11%, were more common in juvenile polyposis (59%) than in juvenile polyps (5%). Among those with juvenile polyposis, colon clearance was achieved in eight, six required colectomy for intractable symptoms, and three were still on the polypectomy program. Polyps recurred in 5% of children with juvenile polyps and 37.5% of those with juvenile polyposis. CONCLUSIONS: Juvenile polyps remain the most common colonic polyps in children. A significant number of cases of polyps are multiple and proximally located, which emphasizes the need for total colonoscopy in all. Juvenile polyps should be removed even if asymptomatic because of their neoplastic potential. Colonoscopic polypectomy is effective even in juvenile polyposis. Surveillance colonoscopy is required in juvenile polyposis only.

Gastroenterol Clin North Am 1997 Mar;26(1):1-17

Colorectal polyps and their relationship to cancer.

Kim EC, Lance P

Department of Medicine, State University of New York at Buffalo, USA.

Autosomal dominant, familial forms of colorectal adenocarcinoma are recognized, but more than 90% of cases are sporadic. Most familial and sporadic cases arise through malignant transformation of benign adenomas in a process known as the adenoma-to-carcinoma sequence. Adenomas are classified histologically as tubular, tubulovillous, or villous. As a neoplasm, adenomas all manifest mild, moderate, or severe dysplasia. The majority (> 90%) of adenomas are small (< 1 cm in diameter) and do not progress. Risk factors for carcinomatous progression include the presence of multiple adenomas, size greater than or equal to 1 cm, and villous histology or severe dysplasia in adenomas of any size. The adenoma-to-carcinoma sequence advances through the accumulation of lesions involving multiple genes. It appears that similar molecular genetic mechanisms are involved in familial and sporadic forms of colorectal neoplasia.

Publication Types:

Review

Review, tutorial

Dis Colon Rectum 1997 Aug;40(8):929-34

Long-term survival after treatment of malignant colonic polyps.

Whitlow C, Gathright JB Jr, Hebert SJ, Beck DE, Opelka FG, Timmcke AE, Hicks TC

Department of Colon and Rectal Surgery, Ochsner Clinic, New Orleans, Louisiana 70121, USA.

PURPOSE: This study was designed to evaluate the long-term outcome and survival of patients treated for malignant colonic polyps. METHODS: A retrospective review of 15,975 cases of colonoscopies with 8,685 endoscopic polypectomies performed between 1972 and 1990 was undertaken. In 65 patients, the polypectomy specimens contained invasive carcinoma. Six patients were excluded (follow-up, <6 months). Polyp data, operative findings, and follow-up on the remaining 59 patients were recorded. RESULTS: Malignant polyps were found in 35 males and 24 females who had an average age of 64 (range, 39-81) years. Follow-up ranged from 12 to 202 (mean, 90) months. Tumor differentiation was poor in one and well or moderately differentiated in 58 patients. Positive or indeterminate margins were found in 13 patients. Thirty-seven (63 percent) patients were managed with polypectomy and surveillance. Four of these (with rectal tumors) also had an additional local excision for questionable margins. One recurrence was noted in a patient who refused surgery, which was recommended because of indeterminate margins. Twenty-two patients (37 percent) underwent colectomy. Indications included Haggitt Level 3 or 4 invasion (19), inadequate margins (7), patient preference (1), and poor differentiation (1). Residual disease was found in colectomy specimens of three patients (14 percent). There were no cancer-related deaths in either treatment group. Life table analysis demonstrated a five-year survival of 82 percent for the colectomy group and 95 percent for the polypectomy group (P = 0.15). CONCLUSION: Treatment of patients with malignant polyps must be individualized based on evolving criteria. Patients in whom polypectomy margins are inadequate should undergo colectomy. With appropriate selection criteria, patients selected for colectomy had a five-year survival rate similar to the rate of those treated by polypectomy alone.

Ann Intern Med 1993 Oct 15;119(8):836-43

Published erratum appears in Ann Intern Med 1994 Feb;15;120(4):347

Polyp guideline: diagnosis, treatment, and surveillance for patients with nonfamilial colorectal polyps. The Practice Parameters Committee of the American College of Gastroenterology.

Bond JH

American College of Gastroenterology, Arlington, VA 22206-1656.

OBJECTIVE: To outline the preferable approach to the management of patients with nonfamilial colorectal polyps. DATA SOURCES: The human subject English language literature for the past 15 years, searched using MEDLINE and the terms "polyp-," "adenoma-," and "polypectomy-colorectal." STUDY SELECTION: The titles and abstracts of all pertinent articles were reviewed. All randomized controlled trials and large case-control and cohort studies related to colorectal polyps were reviewed in depth. DATA SYNTHESIS: Evidence was evaluated along a hierarchy with randomized controlled trials receiving the greatest weight. Conclusions and recommendations were reviewed by a large group of experts in gastroenterology, radiology, and pathology and were circulated for comment to primary care medical societies. CONCLUSIONS: Most patients with polyps should undergo colonoscopy to excise the polyp and search for synchronous neoplasms. Small polyps (< 0.5 cm) require individualization. A hyperplastic polyp found during proctosigmoidoscopy is not an indication for colonoscopy. Large sessile polyps require careful follow-up to ensure complete resection. The need for further treatment of a resected polyp with invasive carcinoma depends on several well-defined clinical and pathologic criteria. Follow-up surveillance after polypectomy should be tailored to the individual risk assessment for each patient. Initial follow-up should be performed at 3 years for most postpolypectomy patients. After one negative result of a 3-year examination, the interval can be increased to 5 years. Patients with one small tubular adenoma do not have an increased risk for cancer, and therefore follow-up surveillance may not be indicated. Adoption of these recommendations should substantially reduce the cost of postpolypectomy surveillance and of screening for colorectal cancer.

Publication Types:

Guideline

Practice guideline

Review

Review, tutorial

Cancer 1992 Sep 1;70(5 Suppl):1236-45

The National Polyp Study. Design, methods, and characteristics of patients with newly diagnosed polyps. The National Polyp Study Workgroup.

Winawer SJ, Zauber AG, O'Brien MJ, Gottlieb LS, Sternberg SS, Stewart ET, Bond JH, Schapiro M, Panish JF, Waye JD, et al

Gastroenterology Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY 10021.

The National Polyp Study (NPS) is a multicenter prospective randomized trial designed to evaluate follow-up surveillance strategies in patients who have undergone polypectomy for the control of large bowel cancer. The study design was developed by a joint research committee from American Gastroenterological Association, the American Society for Gastrointestinal Endoscopy, and the American College of Gastroenterology. Subjects who met the eligibility criteria were randomized into two different treatment arms. Eligibility criteria included: removal of one or more adenomas; complete colonoscopy; no prior polypectomy, inflammatory bowel disease, or familial polyposis; and no history of colon cancer. The treatment arms consisted of a frequent follow-up (1 and 3 years after initial polypectomy) and a less frequent follow-up (3 years). Follow-up examinations included fecal occult blood tests, air-contrast barium enema, and colonoscopy. The latter was done on 9112 referred patients at the seven participating centers from November 1980 until February 1990 who had no history of polypectomy, colon cancer, familial polyposis, or inflammatory bowel disease. Of these patients, 4763 (52.3%) had no polyps; 549 (6.0%) had an invasive cancer; 776 (8.5%) had nonadenomatous polyps; 208 (2.3%) had incomplete examinations; 184 (2.0%) had other findings; and 2632 (28.9%) had one or more adenomas, of which 1418 (53.9%) were randomized to one of the two treatment arms. This article reports the background, rationale, objectives, methods, and organization of this study and includes patient characteristics on initial
presentation. Future data provided by the NPS may help in the development of recommendations for surveillance guidelines for such patients. This study also provides a framework to address questions regarding the natural history of adenomas and their relationship with colorectal cancer.

Publication Types:

Clinical trial

Multicenter study

Randomized controlled trial