Aim:
Breast malignancies continuously shed tumor cells which may enter the circulation,
spread to other tissue and initiate metastases. Adjuvant chemotherapy had been developed
to eliminate these cells and has a firm place in therapy of primary breast cancer.
Currently the majority of patients receive chemotherapy although not all may benefit
from it. Here we confirm in a large cohort of more than 300 patients from a single
institution that it is possible to monitor the response to adjuvant therapy by repeated
analysis of circulating epithelial cells of potential tumor origin (CTC/CETCs) and
to early detect patients who are at risk of relapse.
Methods:
Blood samples were obtained from consecutive patients diagnosed with breast tumors
from 2003 until 2012. CTC/CETCs were enumerated, using an approach avoiding loss of
cells due to enrichment procedures, repeatedly (at least three times) during adjuvant
chemotherapy resulting in a trajectory of cell numbers during this time. Follow up
was up to 12 years.
Results:
Numbers of CTC/CETCs were either observed to decline during chemotherapy, to vary
marginally or to increase versus the end of therapy, sometimes after an initial response
to chemotherapy. Patients with increasing cell numbers were at an increased risk of
relapse as compared to patients with decreasing or marginally changing cell numbers
confirming earlier results.
Conclusion:
Thus, we here confirm the ability of repeated counting of CTC/CETCs during adjuvant
chemotherapy to distinguish already at this early time patients which are at increased
risk of relapse and might warrant more close surveillance.
