ATLANTAExperimental use of laser therapy to destroy small,
localized breast tumors is showing promise as an alternative to
lumpectomy in highly selected patients, researchers from England and
the United States reported at the Era of Hope: U.S. Department of
Defense Breast Cancer Research Program Meeting.
Interstitial laser photocoagulation has been used on about 100
patients with breast cancer and benign fibroadenoma in various
studies that rely on magnetic resonance imaging (MRI), both to detect
small areas of cancer for coagulation and to confirm that no tumor
remains after laser therapy.
All of the breast cancer patients in England and most in the United
States subsequently had scheduled lumpec-tomies. The US team has gone
on to treat three patients with laser ablation alone.
Steven E. Harms, MD, professor of radiology, University of Arkansas
for Medical Sciences, told ONI: The skin heals in the
next few days, and the lump goes away in a few weeks. Patients can
look in the mirror, and they cant see that theyve had any
treatmenttheres no incision, no scars, no deformity.
The 10-minute procedure is done without general anesthesia, he said.
The three patients were sent home with acetaminophen for pain relief
and a bandage strip covering an 18-gauge needle puncturethe
size of needle used to draw blood. A 71-year-old woman took
acetamino-phen for her 3-hour drive home, Dr. Harms said, and the
next day felt well enough to cook Christmas dinner for her family.
Stephen G. Bown, MD, director of the National Medical Laser Centre,
London, added, Laser treatment is a much simpler procedure to
do than surgery, with a lower risk of complications and no hospital
admission required in patients who are otherwise generally fit.
Studies of laser photocoagulation of benign fibroadenomas allowed the
researchers to assess the long-term healing of laser-treated breast
tissue. These studies showed that the necrosis resolved without
complications over a period of months. In one study of 14 patients
with benign fibroadenomas, only one lesion was still detectable by
ultrasound 12 months after laser treatment.
Despite their early successes, both doctors cautioned that, even if
validated by clinical trials, the procedure would only be suitable
for carefully selected breast cancer patients and should not be
considered for any patient whose cancer might have metastasized. Due
to technology limitations, the procedure can only be used on cancers
of 1 cm or less; these have a 20-year disease-free survival rate of
90% with conventional treatment.
Dr. Harms said, While the cosmetic benefits of laser therapy
are significant, the down side of treatment failure would be
terrible. We have to be very careful.
In the laser procedure, up to four needles are inserted through the
skin into a solid tumor. Thin optic fibers pass through the needles
into the targeted lesion. They deliver low-power laser light,
typically 2 to 3 W per fiber, from a semiconductor laser (805 nm) to
coagulate the tumor tissue.
In the experimental treatments done so far, the doctors have found
good correlation between MRI images taken after the procedure and
clinical measurement of the surgical specimen after lum-pectomy.
Differences in British and US health care were reflected in the
follow-up imaging, according to Dr. Harms. In England, breast cancer
patients typically wait several weeks for surgery, so Dr. Bowns
group could take MRI images for comparison weeks after the
patients laser treatments.
In the US, people arent willing to wait 2 weeks for
surgery, Dr. Harms said. Consequently, the Arkansas team did
the follow-up MRIs and lum-pectomies on the same day as the laser treatments.
The quality of the MRI images is crucial because the procedure hinges
on complete detection and destruction of the tumor. Theres
no potential for minimally invasive therapy unless you know where to
target it, Dr. Harms said.
His research group developed software called RODEO (ROtating Delivery
of Excitation Off-resonance) to enhance standard MRIs.
The RODEO images are close to 100% accurate in showing the edges of a
tumor, compared with about 50% accuracy for standard imaging
techniques, Dr. Harms said.
He has shared RODEO with about a dozen cancer centers free of charge,
he said, but it has yet to be licensed by an MRI manufacturer.
The next step is a pilot trial of interstitial laser
photocoagulation, followed by a multicenter clinical trial if all
goes well. Dr. Harms said he has funding for 20 patients in the pilot
study, including the three already treated.