Radioimmunolocalization of pelvic recurrences from rectosigmoid cancer employing 111In anti-CEA F(ab′) 2

Thirty-two immunoscintigraphic studies have been performed in 26 patients previously operated upon for rectosigmoid cancer, for an early detection of pelvic recurrence, employing 111In anti-CEA, F(ab′) 2. The sensitivity was 1, specificity 0.76 and accuracy 0.84, leading to a positive predictive value of 0.69 and a negative value of 1. The combined use of a non-imaging surgical probe in 6 of the 10 patients who underwent second look surgery, detecting the 111In radioactivity used for RIS, improved diagnostic accuracy, ruling out the presence of tumors in 3 patients with false positive RIS.