TPS and CA 15.3 serum values as a guide for treating and monitoring breast cancer patients.

Background: Tissue Polypeptide-specific Antigen (TPS) and CA 15.3 are two of the most widely studied tumor markers in the serum of breast cancer patients. TPS is a tumor associated proliferative marker which belongs to the cytoskeleton. CA 15.3 is a high molecular weight glycoprotein of clinical relevance in the monitoring of treatment and the detection of recurrence in breast cancer patients.
Patients and Methods: Serum values of TPS and CA 15.3 were measured in a prospective series of patients with primary breast cancer (n=267) and benign breast disease (n=46). The cut-off levels (95% specificity) determined for each test were 80 U/I for TPS and 30 k/U/l for CA 15.3.
Results: The diagnostic sensitivity was 0.31 for TPS and 0.32 for CA 15.3 for the detection of breast cancer. Serum TPS levels in breast cancer patients showed a relatively low positivity rate (33%), which was comparable with that of CA 15.3. Higher concentrations of TPS were found in cases with locally more advanced disease as well as in G3 tumors. By contrast, CA 15.3 basal levels were solely related to tumor size and nodal involvement. TPS and CA 15.3 levels were not related to estrogen and progesterone receptor status, peritumoral vessel invasion, multifocality and the in situ component of the tumor. After primary treatment, 20 patients developed distant metastases. In metastatic breast cancer patients TPS was more frequently and more markedly elevated than CA 15.3. In progressive disease, elevated values of TPS and CA 15.3 were found in 85% and 50%, respectively. The mean lead time was 10 months for TPS and 14 months for CA 15.3. Increasing values of TPS were independent of the site of metastasis, whereas elevated levels of CA 15.3 were mainly related to visceral metastasis. Local recurrences were usually associated with low levels of TPS and CA 15.3. By contrast, elevated values of TPS in locally recurred cases indicated rapidly progressive disease.
Conclusions: Our study indicates that TPS and CA 15.3 are not helpful in distinguishing patients with breast cancer from patients with benign breast lesions. Nevertheless, at the time of diagnosis increased serum levels of the markers may facilitate the selection of high risk patients for whom additional treatment and careful follow up studies should be undertaken. Furthermore, TPS seems to be a reliable tumor marker for the early diagnosis of metastatic breast carcinoma independent of the site of metastasis, while increasing values of CA 15.3 are mainly related to visceral involvement.