UTILITY OF CA-15-3 AND CEA IN MONITORING BREAST-CANCER PATIENTS WITH BONE METASTASES - SPECIAL EMPHASIS ON SPIKING PHENOMENA

Objectives: CA 15-3 and CEA are considered useful tumor markers in mon itoring breast cancer patients. This study was undertaken to specifica lly evaluate the transient elevations in these markers that are observ ed during systemic treatment for metastatic disease. This phenomenon h as been termed ''spiking.'' Design and Methods: Serum tumor marker lev els were investigated by enzyme immunoassay in 20 breast cancer patien ts without metastases and in 20 patients with bone metastases receivin g systemic treatment. Results: Both CEA and CA 15-3 levels were signif icantly elevated in the patients with bone metastases. Serum CEA and C A 15-3 levels in patients with metastases displayed a transient, but s ignificant, elevation days 15 and 30, respectively, after commencing s ystemic treatment, which returned to pretreatment levels on the 60th d ay. Conclusions: The spiking effect observed in the tumor marker level s should be carefully evaluated, and not be misdiagnosed as disease pr ogression.