Background

The aim of this project was to investigate the sensitivity of CA 15-3, CEA and HER2 in the early diagnosis of metastatic breast cancer.

Methods

Serial serum values of CA 15-3, CEA and HER2 were determined in 107 patients with recurrence after breast cancer. Fifteen of the patients had primary disseminated disease, nine patients only developed local recurrence during the follow-up period and the remaining 83 developed distant metastases.

Results

In the group of patients with distant metastatic disease (n=83), elevated serum levels of CA 15-3 (>32.4 U/mL), CEA (>2.5 µg/L for non-smokers and >10 µg/L for smokers) and HER2 (>15 µg/L) were found in 49.4%, 38.6% and 32.5%, respectively, at the time of diagnosis of recurrence. CA 15-3 was significantly better than HER2 (p=0.027). The most sensitive combination was obtained using CA 15-3/CEA (60.2%) or CA 15-3/HER2 (57.8%). Combining all three tumour markers raised the sensitivity to 63.9%. In the subgroup of patients with tissue HER2+ tumours, the sensitivity of HER2 increased to 55.6%. The best combination in this group was CEA/HER2 (66.7%). In the subgroup of patients with tissue HER2- tumours, CA 15-3 was significantly better. The best combination was CA 15-3/HER2 or CA 15-3/CEA with a sensitivity of 55.8% and 59.6%, respectively.

Conclusions

The combination of several tumour markers enhances the sensitivity for detection of metastatic breast cancer. We recommend HER2 or the combination of CEA and HER2 in tissue HER2+ and CA 15-3 or the combination of CA 15-3 and CEA in tissue HER2-.