|
Tracy T. Batchelor, MD, MPH, executive director, Pappas Center for Neuro-Oncology, says, “The field of neuro-oncology is rapidly advancing and newer techniques and drugs appear to be increasing the length of time patients live after a GBM diagnosis.”
NPR interview, June 3, 2008
Molecular Guides to Diagnosing Brain Tumors
Accurate biopsy diagnosis is essential for the management of brain tumors since different types are treated in different ways. Specialized neuropathologists from the Massachusetts General Hospital Pathology Service work at the Cancer Center to interpret biopsies to ensure these tumors are treated with the most effective combination of surgery, radiation and drugs.
“It is exciting that our depth of expertise in traditional biopsy interpretation is now complemented by remarkable strengths in molecular diagnosis,” says David N. Louis, MD, chief of Massachusetts General Hospital’s Department of Pathology and Benjamin Castleman Professor of Pathology at Harvard Medical School. Many novel methods now enable pathologists to look directly at abnormal chromosomes and genes in tumors.
Mass General pathologists were the first to show that brain tumors could be diagnosed through the examination of molecular features called "molecular fingerprinting." They were also the first to demonstrate that molecular differences could guide therapies.
For example, future delivery of new smart drugs that target a specific molecule will require precise biopsy analysis to determine which drug will have the greatest chance of destroying a tumor.
New
angiogenesis inhibitor has promise for treating
agresssive brain tumor
Preliminary results show tumor shrinkage, reduction
in edema, normalization of blood vessels
Researchers from the Massachusetts General Hospital (MGH) Cancer Center have
found that AZD2171, a new angiogenesis inhibitor, can reduce
the size of brain tumors called glioblastomas and has the potential
of improving the effectiveness of other therapeutic techniques. The
Phase 2 clinical trial also finds that AZD2171 treatment can alleviate brain
swelling (edema), a debilitating symptom in many brain cancer patients that
currently can be treated only with steroid drugs. Appeared in the
January 2007 issue of Cancer
Cell, the study is too preliminary
to determine whether this new drug may have an impact on overall patient
survival.
“Patients
with recurrent glioblastomas desperately need new, effective treatment alternatives,” says Tracy
Batchelor, MD, MPH, executive director of Stephen
E. and Catherine Pappas Center for Neuro-Oncology, the study’s lead author. “While
these are preliminary results of an initial trial, it’s looking like
these agents may play an increasingly important role in the treatment of
patients whose tumors have recurred and perhaps in newly diagnosed patients
as well.”
Glioblastoma is the most malignant form of brain tumor and has a very poor
prognosis. Standard treatments – including surgery, chemotherapy
and radiation therapy – may delay tumor growth, but patients usually
survive for little more than a year. There are currently no effective
options for patients whose tumors recur, the vast majority of whom die within
6 months.
Angiogenesis inhibitors suppress the growth of blood vessels supplying a tumor
and have received a lot of attention as potential cancer-fighting agents. While
the earliest clinical trials did not meet expectations that these drugs would ‘starve’ tumors,
the agents did improve patient survival when combined with traditional anticancer
therapies. Three anti-angiogenic drugs have received FDA approval
for the treatment of certain tumors, and several others are under investigation. An
oral medication, AZD2171 is a potent inhibitor of the three primary receptors
for the powerful angiogenesis factor VEGF, known be present on glioblastoma
blood vessels. Manufactured by AstraZeneca, AZD2171 is currently available
only to participants in clinical trials.
The
Cancer Center trial, sponsored by the National Cancer Institute,
was designed to assess whether AZD2171 could benefit patients
with recurrent glioblastomas and also if the drug might normalize
tumor vasculature. Blood vessels that develop around
and within tumors are leaky and disorganized, potentially blocking
the delivery of chemotherapy drugs or the effectiveness of
radiation therapy, which requires an adequate supply of oxygen
to the tumor.
The
fact that combining angiogenesis inhibitors with other therapies improved
survival for some patients supports a theory developed by Rakesh
Jain, PhD, director of the Steele
Laboratory in the Department of Radiation
Oncology and senior author of the Cancer
Cell article, that the
agents temporarily ‘normalize’ blood vessels, creating a period
during which chemotherapy and radiation treatment can be more effective.
The paper reports on the first 16 patients to enter the clinical trial, which
began in January 2006. All had glioblastomas that had resumed growing
despite prior radiation or chemotherapy. Participants took a daily
oral dose of AZD2171, which started at 45 mg and could be reduced in those
experiencing negative side effects, including fatigue, diarrhea and hypertension. Participants
were followed with regular physical, neurological, and MR imaging exams during
the 6-month study period.
|
|
|
|
|
|
Imaging studies showed that tumors
began to shrink in most participants within 28 days of the initial
AZD2171 dose. |
| |
|
| |
Overall, the tumors shrank by at least 25 percent in three-quarters of the
study participants and by 50 percent or more in half of the patients. Factors
indicating a normalization of the tumors’ blood vessels – including
reduction in size and a decrease in permeability or ‘leakiness’ – were
seen almost immediately in most participants and continued for at least 28
days, with some features persisting up to four months. These results
are the first to define how long the period of vascular normalization might
last, which may establish a window of time during which applying additional
therapies would be most effective.
The highly advanced MR imaging techniques used in this report,
developed at Massachusetts General Hospital, showed the vascular
normalization to be very rapid, beginning after the first dose
in some patients. Other MGH-pioneered MRI techniques showed
that AZD2171 treatment led to a rapid decrease in brain edema,
an effect that continued as long as the medication was taken. Edema
produces many of the symptoms experienced by brain tumor patients and can
only be treated with steroids, which have negative side effects of their
own. The alleviation of edema allowed several study participants to
reduce or even discontinue steroid treatment.
Analysis of potential biomarkers – molecular and cellular factors that
can be measured in the blood – identified several that may indicate
when the period of vascular normalization is ending or which patients’ tumors
are most likely to become resistant to AZD2171 treatment. These findings
suggest that the imaging and biomarker studies will be important scientific
tools for future assessment of therapy with AZD2171 and other drugs.
“This small group of patients needs to be followed for a longer period
of time, but we are cautiously optimistic that this trial and future studies
will lead to positive long-term outcomes for some patients,” says
Jain. He is the Cook Professor of Radiation Oncology at Harvard Medical
School, where Batchelor is an associate professor of Neurology. The
researchers expect that the complete results of this trial, which enrolled
a total of 31 patients, will be available later this year. They also
are exploring additional trials to further define the role of AZD2171 in
glioblastoma treatment and hope to study the drug in combination with traditional
therapies and in newly diagnosed patients.
Contact Information
For Patient Inquiries
The clinical trial reported in the news media for the drug Recentim is currently
closed. If you live outside of the Boston area and are seeking treatment
for glioblastoma through clinical trials, please contact your physician
for more information.
However, for patients with glioblastoma who live within New England, clinical
trials for this disease are available the Massachusetts General Hospital
Cancer Center through the Stephen E. and Catherine Pappas Center for Neuro-Oncology.
To schedule a consult at the Cancer Center, please contact the Cancer Center
at 877-726-5130.
For Research Professionals
For information on the Edwin
L. Steele Laboratory
For Information on Athinoula A. Martinos Center for Biomedical Imaging: www.nmr.mgh.harvard.edu or
www.martinos.org
Additional News Sources
National Cancer Institute Bulletin
Bloomberg
News
BBC News
Washington Post
Newsday
Health
News - Indianapolis Star
CN8
Interview with Dr. Tracey Batchelor and Dr. Rakesh
Jain on how "Smart Drugs" are leading the
way to new clinical trials in neuro-oncology. (7
minutes)
Back to Top
Different types of radiation therapy for brain tumors including proton beam therapy.
Radiation therapy, which uses high energy x-rays, can destroy remaining cancer
cells after surgery. But it may also be used alone in the rare case when the tumor
is considered inoperable. Almost all patients with malignant tumors receive radiation,
while about one third of those with benign tumors eventually do.
Depending on the needs of the patient, the radiation oncologist may use intensity-modulated
radiation therapy, stereotactic radiotherapy, or proton beam therapy. The mission
of all three forms is to maximize the dose to the tumor and minimize the dose
to nearby healthy tissue.
In intensity-modulated radiation, the strength of the radiation beam is adjusted
to conform to the three-dimensional shape of the tumor. Unlike traditional radiation,
this computer-controlled treatment uses hundreds of very narrow beams to selectively
treat the tumor.
“It is particularly advantageous for a tumor that requires a high dose
of radiation that is near but not touching critical structures,” says
Jay Loeffler, MD, Chief of Radiation Oncology who with his colleague Arnab Chakravarti,
MD, treats adult patients in the Pappas Center. “For example, it allows
us to give a therapeutic dose to a tumor in the lower part of the brain and
largely spare the spinal cord.”
Stereotactic radiotherapy uses focused radiation over a series of treatment
sessions. Under computer guidance, this therapy targets large tumors or ones
located near or within sensitive tissues, such as the optic nerve.
Proton therapy is the newest, and some argue the best, kind of external-beam
radiation. Using proton particles instead of x rays, a beam is created to
match the shape of the tumor. Also known as “no-exit dose” proton
beam therapy, this method directs radiation to the target area, while sparing
the normal tissue beyond it. One of only three centers in the nation, the
Northeast Proton
Therapy Center treats both children and adults with
brain tumors.
Back to Top
New technology allows neurosurgeons to plan and perform brain operations more
safely and precisely than ever before.
Radiation therapy, which uses high energy x-rays, can destroy remaining cancer
cells after surgery. But it may also be used alone in the rare case when the tumor
is considered inoperable. Almost all patients with malignant tumors receive radiation,
while about one third of those with benign tumors eventually do.
Depending on the needs of the patient, the radiation oncologist may use intensity-modulated
radiation therapy, stereotactic radiotherapy, or proton beam therapy. The mission
of all three forms is to maximize the dose to the tumor and minimize the dose
to nearby healthy tissue.
In intensity-modulated radiation, the strength of the radiation beam is adjusted
to conform to the three-dimensional shape of the tumor. Unlike traditional radiation,
this computer-controlled treatment uses hundreds of very narrow beams to selectively
treat the tumor.
“It is particularly advantageous for a tumor that requires a high dose
of radiation that is near but not touching critical structures,” says
Jay Loeffler, MD, Chief of Radiation Oncology who with his colleague Arnab Chakravarti,
MD, treats adult patients in the Pappas Center. “For example, it allows
us to give a therapeutic dose to a tumor in the lower part of the brain and
largely spare the spinal cord.”
Stereotactic radiotherapy uses focused radiation over a series of treatment
sessions. Under computer guidance, this therapy targets large tumors or ones
located near or within sensitive tissues, such as the optic nerve.
Proton therapy is the newest, and some argue the best, kind of external-beam
radiation. Using proton particles instead of x rays, a beam is created to
match the shape of the tumor. Also known as “no-exit dose” proton
beam therapy, this method directs radiation to the target area, while sparing
the normal tissue beyond it. One of only three centers in the nation, the
Northeast Proton
Therapy Center treats both children and adults with
brain tumors.
Researchers in the Pappas Center have pioneered a treatment regimen for CNS lymphoma
that uses chemotherapy without radiation.
Researchers in the Pappas Center, who have pioneered a treatment regimen for CNS
lymphoma that uses chemotherapy without radiation (unless the patient relapses).
Unlike other tumors, CNS lymphoma is treated with radiation to the entire brain,
which, they found, may later affect thinking and memory.
Scientific and clinical research at the Center helps ensure that patients receive
the latest treatments. MGH is a founding member of New Approaches to Brain Tumor
Therapy (NABTT), a national consortium sponsored by the National Cancer Institute
and dedicated to improving outcomes for adults with brain tumors.
Part of Dana-Farber/Partners CancerCare, Pappas Center scientists conduct cutting-edge
clinical research. Last year 64 patients participated in clinical trials for
new drugs, radiation therapy, and gene therapy. Twenty-one trials are currently
underway at MGH. Some of these trials are a joint effort with Dana-Farber Cancer
Institute and Brigham and Women’s Hospital.
In one exciting new study Rakesh Jain, PhD, of the Department of Radiation
Oncology, is investigating whether combining radiation with an antibody that
blocks vascular endothelial growth factor (VEGF) will inhibit angiogenesis or
blood vessel growth. This therapy, which has already yielded dramatic responses
with colon cancer, shows promise for the brain, where tumors depends on new
vessel growth for their nutrient supply.
Proton Beam Therapy May
Improve Rare Tumor
Proton beam radiation therapy may be an effective treatment for advanced adenoid
cystic carcinoma that has spread to the cranial base. Read
More
Back to Top |