Erschienen in:
01.02.2012 | Gynecologic Oncology
Trastuzumab clears HER2/neu-positive isolated tumor cells from bone marrow in primary breast cancer patients
verfasst von:
Brigitte Rack, Julia Jückstock, Maria Günthner-Biller, Ulrich Andergassen, Julia Neugebauer, Philip Hepp, Alexandra Schoberth, Doris Mayr, Thomas Zwingers, Christian Schindlbeck, Klaus Friese, Wolfgang Janni
Erschienen in:
Archives of Gynecology and Obstetrics
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Ausgabe 2/2012
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Abstract
Purpose
Isolated tumor cells (ITC) in the bone marrow of breast cancer patients increase the risk of recurrence and decrease survival, both at primary diagnosis and during follow-up. We tested the efficacy of trastuzumab in clearing HER2/neu-positive ITC from the marrow of patients completing primary treatment.
Methods
Ten recurrence-free patients with persistent HER2/neu-positive ITC after routine adjuvant treatment received trastuzumab 6 mg/kg q3w for 12 months in a non-randomized pilot phase II interventional study. Bone marrow ITC HER2/neu status was evaluated at baseline, after treatment for 3, 6 and 12 months, and yearly thereafter, in combination with clinical follow-up. Median follow-up was 23 (15–64) months after baseline bone marrow aspiration.
Results
Trastuzumab for 12 months eradicated HER2/neu-positive ITC from bone marrow in all patients (P = 0.002) and significantly reduced the number of ITC-positive patients (P = 0.031). However, HER2/neu-negative ITC persisted in three patients immediately after treatment and were detected at yearly bone marrow aspiration in five patients. Two patients with ITC counts ≥5 at yearly follow-up developed metastases and one died.
Conclusion
This is the first evidence that trastuzumab is effective in clearing HER2/neu-positive cells from bone marrow during recurrence-free follow-up in breast cancer patients. It also suggests, thanks to the antigen shift phenomenon, an important prognostic role for HER2/neu expression on marrow ITC as a real-time biopsy. However, treatment was mainly effective in patients with HER2/neu-positive ITC. Given the heterogeneity of minimal residual disease, these patients might benefit from a combination of targeted treatment approaches.