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