Mass Screening for Colo-Rectal Cancer National Institutes of Health
Consensus Development Conference Statement
June 26-28, 1978
This statement is more than five years old and is provided solely for historical purposes. Due to the cumulative nature of medical research, new knowledge has inevitably accumulated in this subject area in the time since the statement was initially prepared. Thus some of the material is likely to be out of date, and at worst simply wrong. For reliable, current information on this and other health topics, we recommend consulting the National Institutes of Health's MedlinePlus http://www.nlm.nih.gov/medlineplus/.
This statement was originally published as: Mass Screening for Colo-Rectal Cancer. NIH Consens Statement 1978 Jun 26-28;1(4):20-22.For making bibliographic reference to the statement in the electronic form displayed here, it is recommended that the following format be used: Mass Screening for Colo-Rectal Cancer. NIH Consens Statement Online 1978 Jun 26-28 [cited year month day];1(4):20-22.
A conference on the screening and early detection of colorectal cancer, sponsored by the Division of Cancer Control and Rehabilitation of the National Cancer Institute, was held June 26-28, 1978. This is one of a series of consensus development meetings to examine aspects of medical technology which may be ready for broad scale demonstration programs in the community and to develop useful information which can serve as the basis for public and physician education programs. The objective of the conference was to evaluate the scientific evidence related to colorectal screening. A detailed summary and meeting proceedings are in preparation.
Many disciplines were represented on the conference agenda including gastroenterologists, epidemiologists, oncologists, surgeons, pathologists, economists, internists, and family practitioners. The steering committee consisted of Dr. Joseph T. Painter (chairman), Vice President, University of Texas Systems Cancer Center; Dr. Thomas P. Almy, Third Century Professor of Medicine, Dartmouth Medical School; Dr. George Hutchison, Professor of Epidemiology, Harvard School of Public Health; Dr. Charles G. Moertel, Chairman, Department of Oncology, Mayo Graduate School of Medicine; and Dr. Paul Sherlock, Chairman of Department of Medicine, Memorial Sloan-Kettering Cancer Center. Although all methods of screening and early detection were covered, the conference primarily examined stool occult blood testing as a screening technique for colorectal cancer. A number of studies were reviewed, including the results of clinical trials for occult blood testing for detection of colonic neoplasms in the U.S. and Germany. Proctosigmoidoscopy as a screening tool was not discussed in detail, as it is known that physician utilization has been low secondary to poor patient and physician acceptance of rigid sigmoidoscopy.
The steering committee has agreed to the following recommendations as applied to screening. These recommendations do not apply to persons who present with symptoms which could be related to colorectal cancer who will require complete diagnostic workup which might include any or all of the tests mentioned.
- There are insufficient data to date to indicate that screening for colorectal cancer by stool occult blood testing reduces mortality from the disease in screened populations participating in clinical trials. More time is needed for the ongoing clinical trials to collect enough additional data before it will be possible to assess survival benefit, risk possibilities, and economic feasibility. Although it is recognized that decisions must sometimes be based on incomplete evidence, caution is advised in the development of public policy recommendations about population screening programs for colorectal cancer at this time. This recommendation is based upon the absence of a clear demonstration of (a) improved survival rates in screened individuals with colon cancer or (b) a net margin of benefit to health in comparison with the costs and risks entailed in the further study of all positive occult blood reactions by barium enema or endoscopy.
- Until more knowledge of the benefits and risks of screening for this cancer site is available, mass screening demonstration programs should not be initiated by the Division of Cancer Control and Rehabilitation, NCI.
- Additional clinical investigations are strongly urged before occult blood testing can be endorsed for general use. However, because the method is commercially available for unregulated use by practicing physicians or other health care service providers, the following guidelines for professional use are recommended:
- a statement that benefit/cost/risk indices cannot be determined at this time;
- a statement that in the light of present information, the uncontrolled application of the method outside of special evaluation studies may not represent a wise use of health care resources and may not be of benefit to the recipients of the intervention;
- where used the technique should be limited to asymptomatic men and women over the age of forty unless there are additional personal or familial risk factors;
- where used the procedure should include:
- meat-free high fibre diet prior to testing
- storage of specimens for less than 4 days before testing no rehydration of slides when using Hemoccult II slides
- the recording of all results as positive or negative. Doubtful readings should be recorded as negative and trace readings as positive
- the handling of a single positive slide as if all slides are positive
- at present all positive tests should be followed by complete examination of the colon by radiological and/or endoscopic means;
- follow-up expertise and facilities for diagnosis and treatment should be readily available; and
- fecal occult blood testing should not be used at present as a substitute for proctosigmoidoscopy or as a basis for clinical decisions in patients with symptoms of colorectal cancer.
- The major controlled clinical research trials which are evaluating colorectal cancer screening using occult blood testing should be continued. These are (1) the evaluation of occult blood testing performed annually in a study group as a part of the patient examination in the Preventive Medicine Institute--Strang Clinic in collaboration with the Memorial Sloan-Kettering Cancer Center; and (2) and evaluation of occult blood testing in combination with a diagnostic protocol in a control group, an annual screening group and a biennial (every 2 years) screening group at the University of Minnesota.
- Since all evaluations of screening must be geared to the proper interpretation of the pathology, including all the histologic variations in adenomas and the premalignant and malignant changes that may occur within them, the development of a uniform interpretation and nomenclature is needed. Workshops for this purpose may be useful.
- Professional organizations should educate the radiological, medical and surgical communities regarding the importance of an air contrast study in addition to the standard barium enema in the radiological examination of the patient suspected of having a colonic neoplasm or a small polypoid lesion.
- Professional organizations should encourage the assumption of responsibility by physicians for adequate cleansing of the colon in preparation for barium examinations. The risk and expense of this examination are not justified in poorly prepared patients.
- The following are recommended to clarify the role of flexible sigmoidoscopy:
- comparison of the value of flexible sigmoidoscopy with that of rigid sigmoidoscopy in a total program of detection of asymptomatic colonic neoplasms;
- the evaluation of the possibility of training general internists and paraprofessionals to use flexible sigmoidoscopes adequately;
- comparison of the relative value of several different lengths of the flexible sigmoidoscope for examination by screening physicians; and
- comparison of the value of flexible sigmoidoscopy plus air contrast barium enema with that of endoscopy of the total colon (colonoscopy). The combination of flexible sigmoidoscopy and air contrast barium enema is considerably less expensive and may be more generally available. If the two are equally effective in a screening setting, the less expensive flexible sigmoidoscopy and air contrast barium enema could be an alternative approach.
- The following are recommended in high-risk groups:
- The organization of cooperative studies to establish the proper surveillance procedures for high-risk groups. Currently, there are no available data on the choice of surveillance methods for the follow-up of these patients. High-risk groups include persons with inflammatory bowel disease (both ulcerative and granulomatous colitis), persons with various familial polyposis syndromes, persons with a strong family history of site-specific cancer of the colon, persons in cancer families where colon cancer, endometrial cancer, and breast cancer seem to be clustered, and patients who have had a previous adenoma or colon cancer removed. Cooperative studies in high-risk groups may be of value in the evaluation of diagnostic procedures, the effects of diet on the prevention of cancer and other population studies.
- The development of at-risk profiles and registries of those at high risk. Various centers need to pool and exchange information about profiles and to perform identifying tests requiring skills not available at every center.
- The investigation of dye scattering techniques and other methods to identify dysplastic lesions. These should reduce the need for multiple biopsies in patients with ulcerative colitis.
- The development of innovative approaches to identify persons in the general population who are at high risk for colon cancer not included in the known high-risk groups above.
- Research to identify immunologic and biochemical markers in colonic washings, blood, and urine should be strongly encouraged.
National Cancer Institute
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