USE OF TRUQUANT BR RADIOIMMUNOASSAY FOR EARLY DETECTION OF BREAST-CANCER RECURRENCE IN PATIENTS WITH STAGE-II AND STAGE-III DISEASE

Purpose: The Truquant BR radioimmunoassay (RIA) (Biomira Diagnostics I nc, Rexdale, Canada) uses the monoclonal antibody B27.29 to quantitate the MUC-1 gene product (CA 27.29 antigen) in serum. We evaluated CA 2 7.29 antigen in a controlled, prospective clinical trial for its abili ty to predict relapse in stage II and stage III breast cancer patients . Patients and Methods: Over a 2-year period, 166 patients who had com pleted therapy for stage II (80.1%) or III (19.9%) breast cancer and w ere clinically free of disease were serially tested for CA 27.29 antig en levels, The study was double-masked and cancer recurrence was docum ented based on clinical findings, patients with two consecutive CA 27. 29 antigen test results above the upper limit of normal were considere d positive, Results: The Truquant BR RIA had a sensitivity of 57.7%, s pecificity of 97,9%, positive predictive value of 83.3%, and negative predictive value of 92.6%, The recurrence rate was 15.7%, A Cox regres sion analysis showed that the only variable to correlate with recurren t disease was the CA 27.29 antigen test result, patients with a positi ve test result had increased odds of having a recurrence (odds ratio, 6.8; P < .00001), The test was effective in predicting recurrence in p atients with both distant and locoregional disease, In a subgroup of p atients with bone pain, CA 27.29 antigen level was found to identify r eliably patients who would subsequently develop recurrent disease, Con clusion: These data demonstrate that the Truquant BR RIA con be used a s on aid to predict recurrent breast cancer in patients with stage II and III disease. (C) 1997 by American Society of Clinical Oncology.