Results
Patient characteristics
Six hundred and two patients were recruited for the
study between September 2003 and January 2009. This
included 404 patients with stage I to III breast cancer.
Their age ranged from 29 to 90 years (mean and median
of 59). Ninety-seven were found to have a benign breast
tumor and were placed in a control group. One hundred
and one patients were excluded; 48 with DCIS, 42 due
to insufficient data, 5 with unreliable CTC measurements,
4 patients turned out to have stage IV breast
cancer at inclusion, 1 patient was male, and in 1 patient
there was no known primary tumor. Demographics and
baseline characteristics of the included patients are
shown in Table 1. A total of 84.7% of patients were ERpositive
and 71.8% were PR-positive, but only 47.5% of
patients received adjuvant hormonal therapy in accordance
with Dutch national guidelines, which shows that
our study includes a large group of patients with relative
favorable characteristics. Twenty-seven of 81 Her2 positive-
patients received adjuvant treatment with trastuzumab.
Adjuvant treatment with trastuzumab was started
at our hospital at the end of 2005.