New research presented at the 93rd annual meeting of
the American Association for Cancer Research (AACR) suggests that monitoring
with the serum HER2/neu oncoprotein test may help oncologists assess the effect
of trastuzumab (Herceptin)-based therapy in patients with metastatic breast
cancer. These data add to the growing body of evidence supporting the value of
the serum HER2/neu oncoprotein test in the management of patients with
metastatic breast cancer.
Serum monitoring provides a "real time" picture of a woman’s
changing HER2/neu levels, enabling oncologists to evaluate the effectiveness of
a particular therapy. Studies have shown that decreasing HER2/neu values reflect
response to therapy, while increasing values may indicate progressive disease.
Data from the study supported the value of the serum HER2/neu oncoprotein
test in early prediction of response to trastuzumab-based therapy in metastatic
breast cancer patients. Trastuzumab works by targeting cancer cells that
overexpress the HER2 protein, and slowing or stopping the growth of these cells.
The study was designed to examine whether serial monitoring of serum HER2/neu
levels in metastatic breast cancer patients can predict or parallel response to
therapy. A total of 3,122 serum samples were taken from 75 women at baseline,
and again immediately prior to each infusion of trastuzumab. A decline in serum
HER2/neu levels over time correlated to response to trastuzumab. Specifically,
the ratio of baseline serum levels to the levels monitored throughout the course
of treatment was significantly higher among patients responsive to therapy than
among those who did not respond (P ≤ .01). This predictive value was apparent
after the first infusion of trastuzumab.
"These data suggest that monitoring with this oncoprotein blood test can
help physicians treat their metastatic breast cancer patients," said Dr.
Wolfgang Johannes Köstler, clinical division of oncology, department of
internal medicine at University Hospital in Vienna. "In addition to the
health implications, optimizing treatment may also have a positive impact on