Evaluation of CA 15-3 tumor marker in the diagnosis of breast cancer. A pilot study.

Single determinations of serum CA 15-3 levels were performed by sandwich enzyme immunoassay in 160 women: 77 patients with nonmalignant breast tumors (64 had fibrocystic disease, 11 had fibroadenoma, 2 had intraductal papilloma) and 83 patients with primary breast cancer prior to any treatment; the cut-off limit was established at 30 U/ml. The overall diagnostic sensitivity and specificity of the CA 15-3 test was 19.3% and 94.8%, respectively. The positive and negative predictive values were 80.0% and 52.1%. The mean CA 15-3 value was significantly lower in patients with benign breast tumors as compared with the breast cancer group: 16.8 +/- 8.2 vs. 23.9 +/- 20.9 U/ml (p < 0.01) as well as the percentage of positive results of the test: 5.2% vs. 19.3% (p < 0.02). Serum CA 15-3 level in breast cancer patients correlated with: (1) clinical stage: a higher percentage of positive results was observed in patients with more advanced cancer: Stage I-0%, Stage II-10.6%, Stage III-29.6%, and Stage IV-100.0% according to UICC classification; the comparison of breast cancer patients with early stage of disease (I+II) and those with more advanced cancer (III+IV) revealed statistically significant (p < 0.01) difference in the mean serum CA 15-3 value (19.7 +/- 12.8 vs. 31.5 +/- 29.2 U/ml) as well as in the percentage of positive results (9.4% vs. 36.7%, p < 0.01); (2) the histological grading according to Bloom and Richardson: 5.41% of positivity was observed in low and intermediate grade cancers (I+II) vs. 66.7% in grade III (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)