Evaluation of serum CA15-3 determination with CEA and TPA in the post-operative follow-up of breast cancer patients.

The usefulness of post-operatively serial serum CA15-3 determination with CEA and TPA was evaluated in a group of 285 breast cancer patients. In particular, the CA15-3 sensitivity to 'early' diagnosis and monitoring of the response to treatment of breast cancer relapses, was compared with those of the two other markers in order to define the most suitable association. Moreover, in a group of 169 non relapsed patients with a prolonged follow-up (40 +/- 8 months; mean +/- s.d.) CA15-3 specificity was investigated. During post-operative follow-up in 27 (10%) patients, distant metastases occurred. In most of them, elevated values of one or more tumour markers were the first pathological sign and CA15-3, CEA and TPA sensitivity to 'early' diagnosis of metastases were 46%, 7% and 63% respectively. When each tumour marker was considered in combination, CA15-3-CEA-TPA association showed a higher sensitivity (87%) than both CA15-3-TPA (83%) and the CEA-TPA (70%). Serum CA15-3 increase preceded the certain sign of metastases 2.7 +/- 2.6 months (mean +/- s.d.). Shortly before appearance and during treatment of distant metastases, constant elevation and/or progressive increase in serum CA15-3 values occurred in all evaluated patients except three in whom isolated elevated values were found as well. In 24 (14%) of 169 non relapsed patients with prolonged follow-up (40 +/- 8 months; mean +/- s.d.) high serum CA15-3 values occurred. In 16 of these 24 patients, an isolated elevated value was found, while four (2.3%) or the eight remaining ones with constant elevation and/or progressive increase were falsely suspected of metastases. In this group of non relapsed patients, chronic liver failure, diabetes and/or hepatic steatosis were the reasons more commonly responsible for the CA15-3 increase. In metastatic patients, no organ-specificity was shown either by CA15-3 or by CEA and TPA. In these patients serum TPA values showed the highest sensitivity and paralleled clinical and/or instrumental signs better than the CA15-3 and even more than CEA values. These data indicate that in the post-operative follow-up of breast cancer patients, TPA is the most useful tumour marker and TPA-CA15-3 the most suitable association. Contemporaneous measurement of serum CEA levels only slightly increases sensitivity and positive predictive value of TPA-CA15-3 combination.