Modern approaches to early identification of large-bowel cancer

Abstract

Prospects for future improvement in survival from colon cancer may depend on advances in our knowledge of biochemical and immunological alterations that occur in malignancy. However, even when these tests indicate an abnormality, all current methods would have to be used to localize a lesion to obtain a tissue diagnosis. At present we must work primarily with all of our investigative tools in order to make a diagnosis in the symptomatic patient. However, intensive, periodic, selective investigation of high-risk patients such as those with familial polyposis, previous polyps or cancer, or ulcerative colitis are sure to be rewarding. An additional high-risk population could be identified by testing the stools of the asymptomatic patient for occult blood. These patients could then be studied with an aggressive diagnostic approach including sigmoidoscopy, colonoscopy, blood CEA, and newer techniques such as pulsatile lavage for CEA in the washings, for cytology, fluorescent cytology, enzymes, and for isotopic labeling. It is clear that if we are to salvage larger numbers of patients, very early diagnosis, or diagnosis in the incipient stage of disease, is vitally needed. Indications are that findings from some of the studies discussed may in the foreseeable future lead to useful clinical application which will meet this need for the early detection of colon cancer.