Early diagnosis is most important in the prognosis in colorectal cancer because the cause of cancer is unknown and an effective and practical large-scale screening test, easily and cheaply carried out, is unavailable. If the diagnosis is made early, when the patient is asymptomatic, and prior to development of complications or when the lesion is precancerous, the disease almost always is localized and adequate treatment gives excellent results. However, if symptoms have been present for months or complications have developed prior to establishing the diagnosis (because of patient neglect in seeking advice or physician lack of tenacity in evaluating the patient's condition), or if surgical treatment has been inadequate, the prognosis is poor. Education of physicians and the public remains most important in improving results further. New knowledge or new modalities of treatment should result in improved prognosis not only in colorectal cancer but also in cancer of other anatomic sites.
HE PROGNOSIS IN CANCER OF THE COLON
T and rectum involves early diagnosis, treatment of known precancerous lesions, extent of initial treatment of the cancer, fac-to1 c related to that treatment, and adequacy of Follow-up. If the cause of cancer were known, attention would be directed along different lines-those of prevention and tlie use of other modalities in management. Hopefully, discoveries in the fields of immunology, viiology, host resistance, and the true role of regional lymphatic vessels and nodes, will lead to ;L new approach. dn the meantime, con1 inuetl effort must be directed mainly toward earl! diagnosis and adequacy of treatmen t.
,4mong neoplastic diseases, cancer of the colon and rectum has become a most important socioeconomic problem as well as a medical one. Each year, approximately 75,000 people in the United States develop cancer of this part of the intestinal tract, and almost 45,000 patients (60y0) die from it. Three of every four patients might be saved by earlier diagnosis and prompt and adequate treatment.1 Programs for education of the public and physicians, development of cancer detection cen-