Thursday, June 5, 2003
N.H. – A form of vitamin D has been found to greatly enhance radiation
treatment for tumors associated with breast cancer, according to a new
collaborative Dartmouth Medical School study.
The findings support the potential benefits of combining a vitamin D
analog with radiation to wipe out radiation-resistant cancer cells.
radiation therapy is a common course of treatment after a malignant tumor is
surgically removed, there are often cells that are resistant to radiation that
may cause a recurrence of cancer in the patient’s future.
When combined with radiation, the vitamin D analog EB 1089 is capable of
wiping out radio-resistant cells that may be present following the surgical
removal of a tumor in a clinical situation.
study, published in the June issue of the Journal of Clinical Cancer Research,
compares tumor growth in mice treated with radiation alone and mice exposed to
radiation and EB 1089, a derivative of vitamin D. Final tumor volume in animals irradiated with EB 1089 was
approximately 50 percent lower than in the group that received radiation alone.
results of our latest study with EB 1089 are very encouraging,” said lead
author, Dr. Sujatha Sundaram, assistant research professor at Dartmouth Medical
School. “The vitamin D analog has
proven effective in enhancing radiation treatments in our prior studies with
cell cultures and now in live mice. We are eager to push ahead to clinical
trials with breast cancer treatments in humans.”
year approximately 200,000 women in the United States are diagnosed with breast
cancer. Of that number, about
40,000 die from the disease, making breast cancer the leading cause of cancer
deaths among women between the ages of 20 and 59, according to the American
Cancer Society. Radiotherapy is
commonly used to treat breast cancer, both before surgery to reduce tumor size
and after surgery to reduce tumor recurrence.
There has been increasing
evidence that vitamin D – naturally manufactured by the body after exposure to
sunlight – helps to prevent and treat several forms of cancer.
But too much vitamin D has been found to induce excessive calcium that
can affect bone metabolism and structure. The
vitamin D analog EB 1089 has a modified chemical structure which has
significantly fewer calcium-related side-effects. “It is relatively nontoxic,
especially when compared to chemo-therapy treatments that cause hair loss, loss
of appetite and several other side-effects,” said Sundaram.
is the first study to combine the vitamin D compounds with radiation, and
“demonstrates a clear advantage in combining EB 1089 with irradiation in the
control of breast tumor growth,” state the researchers.
always trying to find drugs that will prevent cancer from recurring, yet be less
toxic to the patient than the current chemotherapy regimens," said study
co-author David A. Gewirtz, Ph.D., Virginia Commonwealth University Medical
Center in Richmond, Va. "We're seeing very encouraging results in cell
culture and animal studies when we add vitamin D analogs to radiation
authors are optimistic that these findings could offer a significant benefit to
patients suffering from radiation-resistant brain tumors and prostate cancer,
not just breast cancer. They
acknowledge that there are limitations in studies that use animal models to grow
human tumors and say additional trials are needed.
The analog EB 1089 is currently in clinical patient trials in Europe for
the treatment of cancer, although it is not being used with radiation therapy.