[Routine use of serial plasmatic CA 15-3 determinations during the follow-up of patients treated for breast cancer. Evaluation as factor of early diagnosis of recurrence].

Purpose: at our institution, CA 15-3 assays are routinely used for the early diagnosis of recurrence during the follow-up of patients treated for breast cancer, although published guidelines do not recommend this procedure. So, we decided to totally re-assess the usefulness of this policy.
Patients and Methods: all records of patients presenting a first recurrence, local (50 cases) or metastatic (88 cases), of breast cancer during 2003 were re-examined. An increase in CA 15-3 concentration of more than 25% was considered significant.
Results: an increase was observed in 18% of non metastatic recurrences. These increases had a prognostic value. CA 15-3 levels remained stable in 23% of metastasis cases and increased in 77%. In 14% of cases, the increase in CA 15-3 levels confirmed a clinically or radiologically suspected metastasis. Moreover, increased CA 15-3 levels in the absence of suggestive clinical or radiological signs led to the diagnosis in 18% of metastasis, 50% of which involved the bone.
Conclusion: our study demonstrates that CA 15-3 is useful for the early diagnosis of recurrence. Eighteen per cent of metastases were diagnosed by a marker increase alone. CA 15-3 assays could be useful in the early management of these metastases in patients treated for breast cancer.