Decision making using postoperative CEA and CA 15-3 for detection of breast cancer recurrence

To determine the clinical implications of postoperative levels of serum carcinoem-bryonic antigen (CEA) and CA 15-3 as follow up parameters for breast cancer, a retrospective study was conducted on 157 patients who underwent curative surgery for breast cancer. Twenty-three patients had recurrences and 134 patients were without recurrence for more than one year after measuring the tumor markers. The receiver operating characteristic (ROC) curves indicated that CA 15-3 performed more accurately than CEA in discriminating between patients with recurrence (n = 23) and those without (n=134). Of 23 patients with recurrence, CEA was elevated above the normal range (>2.9 ng/ml) in 32% and CA 15-3 was elevated above the normal range (> 20 U/ml) in 67%. The elevation of the markers preceded the clinical appearance of metastases in 2 patients for CEA and in 5 patients for CA 15-3. False positive rates for CEA and CA 15-3 in the 134 patients without recurrence were 4% and 10%, respectively. Nevertheless, these rates became 0% when the cut-off values were doubled. When the postoperative serum level of either CEA or CA 15-3 exceeds twice the upper limit of the normal range or when, in patients with unfavourable prognostic characteristics (node positive or large tumor), either of these values is between the upper limit of the normal range and double the value, recurrent breast cancer must be assumed. For such patients, further investigations with high-sensitivity radiographic modalities are warranted because early treatment may be able to provide survival benefit.