Monitoring circulating epithelial tumour cells (CETC) to gauge therapy: in patients with disease progression after trastuzumab persisting CETC can be eliminated by combined lapatinib treatment.

BACKGROUND

In breast cancers, the gene for the growth factor receptor HER2 can be amplified leading to increased aggressiveness and metastasis formation. The monoclonal antibody trastuzumab prolongs relapse-free survival highly significantly but eventually many patients relapse.

METHOD

In this study, CETC were monitored using the Maintrac method during adjuvant trastuzumab treatment and during subsequent treatment with capecitabine/lapatinib.

RESULTS

In one patient, trastuzumab led to marginal reduction in CETC with disease progress. The combination of capecitabine/lapatinib was preliminarily capable to eliminate all CETC, however, CETC reappeared. The second patient received adjuvant taxane together with trastuzumab and 1 year of further trastuzumab during which CETC increased. After stopping trastuzumab skin metastases occurred. Capecitabine/lapatinib led to complete CETC elimination with stable disease.

CONCLUSIONS

In patients with lack of CETC reduction in spite of trastuzumab treatment correlated with disease progression the combination of capecitabine/lapatinib highly efficiently led to rapid elimination of CETC warranting further monitoring during such studies.