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.