THE ROLE OF IMMUNOSCINTIGRAPHY IN THE STAGING AND MANAGEMENT OF COLORECTAL-CANCER

Colorectal cancer has continued to increase in incidence over the past -25 years, It now ranks as the second most common noncutaneous maligna ncy for men and women together. The projected 1995 statistics predict 153,000 new cases in the United States, with 109,000 of colonic origin and 44,000 cancers of the rectum. The shift to more proximal colonic involvement and a decrease in size of the presenting lesion is again n oted. Unfortunately, the warning signals (rectal bleeding, change in b owel habits and, later, abdominal pain, distention, and weight loss), often become evident only after the tumor has progressed significantly in the patient. Despite improvements ill endoscopic detection, anesth esia, pre- and postoperative care and more extensive en-bloc resection s, the cure rate for all patients with colorectal cancer remains uncha nged at 53 per cent at five years. Although radical resectional surger y is relied on for locoregional control of the disease, there has been an increased use of cross-sectional radiologic studies for staging of the cancer. This newer management of colorectal cancer is the result of a better understanding of the natural history and biologic behavior of the cancer. The main strategy presently is to diagnose the disease sooner, stage the cancer more accurately, select tumors that will res pond to adjuvant therapy, and detect recurrences more efficiently. It is in the area of staging of the primary tumor and accurate localizati on of recurrences that this. new modality, immunoscintigraphy, is felt to have an impact.