The use of blood tumour markers in the monitoring of metastatic breast cancer unassessable for response to systemic therapy

The role of blood tumour markers is established in the monitoring of respon se to systemic therapy for patients with metastatic breast cancer assessabl e by UICC criteria. This paper examines the use of marker measurements (in the form of a previously devised biochemical index score comprising CA15.3, CEA and ESR) in patients with metastatic lesions unassessable for response by UICC criteria. Of 218 patients with metastatic breast cancer treated ov er a 2-year period in the Nottingham Breast Unit, 43 patients (20%) had una ssessable disease and 36 of them with blood marker results available were s tudied. Eighty-six per cent of patients were biochemically assessable. All patients who achieved biochemical response remained unassessable by UICC cr iteria. Twenty-two patients progressed initially or subsequently (after an initial biochemical response), either biochemically or by UICC criteria. Bi ochemical assessment completely paralleled UICC assessment in all eight pat ients who progressed by both assessments. Biochemical progression occurred ahead of UICC assessment in four of them with a median lead-time of 4.5 mon ths. Biochemical assessment by blood tumour markers is useful in patients w ith metastatic breast cancer unassessable for response to systemic therapy. These findings need to be confirmed in a larger patient series.