| Future study of colorectal cancer will refine our | | | | goal would be to collect a set of markers for cancer |
| understanding of the genetics of the disease. This in | | | | risk for an individual who has adenomatous polyps. |
| turn will lead to earlier identification and treatment of | | | | Presumably, such testing could reflect exposure to |
| high-risk persons. The future may possibly bring the | | | | colon carcinogens and help define the outlook for an |
| use of genetic interventions to interrupt the | | | | individual. This in turn could narrow the prospective |
| adenoma-carcinoma sequence. | | | | use of screening and diagnostic procedures such as |
| Increased awareness of colorectal cancer by the | | | | colonoscopy. |
| public and by private insurers, government agencies, | | | | Techniques to identify micrometastases in lymph |
| and medical personnel will result in better use of | | | | node tissue are in development. These include special |
| available screening techniques. Development of | | | | stains for cytokeratin, which can identify small |
| preventive drug strategies against colorectal cancer, | | | | clusters or single malignant cells in lymph node tissue. |
| particularly with drugs that reduce polyp formation or | | | | Another method uses a technique known as PCR for |
| prevent polyp progression to cancer, promises to be | | | | detection of CEA in resected lymph nodes. PCR is a |
| a fruitful field of endeavor. | | | | technique which permits rapid reproduction of large |
| There is ample reason to expect refinement of | | | | quantities of short segments of DNA or RNA. |
| diagnostic and staging tests for the disease, | | | | Other techniques include the identification in lymph |
| perfection of surgical and nonsurgical techniques for | | | | node tissue of oncogene, or tumor suppressor gene |
| treatment of large bowel cancer and its | | | | mutations, which occur in the primary tumor. Such |
| complications, and improving chemotherapeutic | | | | techniques may be of use in reclassifying patients |
| treatment by means of more effective and less | | | | whose lesions are stages as II or B by conventional |
| toxic drugs. | | | | means and in selecting them for potentially life-saving |
| A number of molecular markers for colorectal cancer | | | | adjuvant chemotherapy. Large clinical trials will be |
| can be measured but it is not yet clear that they | | | | needed to determine if identification of |
| have prognostic value or therapeutic implications. | | | | micrometastases by these methods indeed leads to |
| Measures of DNA synthesis or cell division are of | | | | more appropriate treatment and improved progress. |
| uncertain value as clinical decision-making tools. | | | | Expression of the enzyme COX-2 by colorectal |
| Measurement of thymidilate synthase activity in | | | | cancers is highly variable. Greater expressions of |
| colorectal cancer tissue is one of several markers | | | | COX-2 by tumors are associated with lymph node |
| under investigation as a prognostic indicator. | | | | metastasis, advanced stage of cancer, and poorer |
| This could be useful in making decisions regarding the | | | | long-term outlook for patients. Thus, there could be |
| use of adjuvant chemotherapy for certain patients, | | | | potential future application of this test as a means of |
| especially those with stage II or B tumors. Another | | | | staging and prognostication. |