Magnetic resonance imaging can help predict recurrence of breast cancer
19 June 2005
A US study of breast cancer patients has found that measurement of breast
tumour volume before, during and after chemotherapy using magnetic resonance
imaging (MRI) can help predict whether a patient’s cancer will return.
The study, performed at the University of California-San Francisco, of 58
breast cancer patients found that the best way to predict a patient's
recurrence-free survival is to review the initial MR examination (before the
patient has chemotherapy) and the final MR examination (after chemotherapy
has been completed). “Initial tumour volume was a strong predictor of
recurrence free survival. Of the women who had tumour volumes of 33 cm3 or
less on the initial MR exam, 93% remained disease free after two years,
compared with 70% of the women with larger tumours. This speaks strongly for
the value of early detection,” said Savannah C. Partridge, PhD, now an
assistant professor of radiology at the University of Washington, Seattle.
“The change in tumour volume with treatment was also a valuable
predictor,” said Dr. Partridge. “We found that the group of patients who had
a 50% or greater reduction in MRI tumour volume when comparing the first MR
examination to the last had a better recurrence-free survival rate (87%
remained disease-free after two years) than those with less tumour shrinkage
during chemotherapy treatment (64% were disease-free after two years),
irrespective of their initial tumour volumes,” she added.
One patient with a large focal mass showed a substantial decrease in
tumour volume on MRI during treatment, and continues to be disease-free 40
months after surgery. In contrast, a second patient, with a more diffuse
mass, showed an increase in tumour volume on MRI during treatment that was
not detected by clinical examination. Her disease returned eight months
after surgery, said Dr. Partridge.
Most often, MRI is used to measure the tumour's diameter, said Dr.
Partridge. “This study shows that while measuring tumour diameter is useful
for staging, volume is preferable for monitoring treatment because 3D volume
measurements can more accurately capture the extent of irregularly shaped
tumours, multifocality and diffuse shrinkage of lesions during treatment,”
she said. “It is important that an accurate and validated tool be used for
calculation of 3D tumour volume from MRI images,” she noted.
Physicians now typically evaluate treatment response by clinical exam and
pathology. “But unlike pathology, early changes in tumour volume can
potentially be assessed by MRI at a time when chemotherapy regimens can
still be modified. Our study showed that MRI measurements of breast tumour
volume can help predict recurrence-free survival. We are encouraged by these
results and anticipate that monitoring tumour response by MRI will help us
to better tailor treatment strategies for individual patients. A larger
multi-center study is currently underway to see if MRI can determine if
chemotherapy is working early enough for treatment to be changed,” she said.
The study appears in the June 2005 issue of the American Journal of
Roentgenology. AJR Jun 2005;184:1774-1781
Source: American Roentgen Ray Society (ARRS)