Summary

Background: Previous studies have suggested that prolactin may serve as an indicator of disease progression in breast cancer.

Objectives: To evaluate the use of PRL as a serum tumor marker in patients with breast cancer.

Methods: PRL serum level was determined in 99 breast cancer patients and compared with CA 15-3 serum level.

Results: Elevated serum level of PRL (>20 ng/ml) was found in 8 of 99 patients (8.1%). A stratified analysis of prolactin levels according to therapy revealed that PRL levels was increased in 8 of 55 untreated patients (14.5%), but not in patients who received hormonal or chemotherapy in the 3 months preceding the test (0/42 patients, P=0.009). However, mean PRL level was similar in patients with no evidence of disease activity and in patients with active disease (10.2 vs. 8.2 ng/ml, NS). In comparison, CA 15-3 mean level was significantly lower in patients with no evidence of disease as compared to patients with active disease (18.2 vs. 144.7 units/ml, P<0.001). PRL level was increased in 6 of 60 patients (10%) with no evidence of disease and in 2 of 39 (5.2%) with active disease (NS). In comparison, CA 15-3 level was increased in 3 of 60 patients (5%) with no evidence of disease and in 24 of 39 (61.5%) with active disease (P<0.001).

Conclusions: PRL levels are decreased following hormonal or chemotherapy in patients with breast cancer and there is no correlation between PRL serum level and the state of disease. Further studies are needed to clarify a possible clinical significance of hyperprolactinemia in a subset of patients with breast cancer.

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PRL = prolactin