New Treatment Shrinks Kidney Tumors
By DENISE GRADY
An experimental treatment for advanced kidney cancer has shrunk
tumors or wiped them out completely and prolonged life in some
patients for whom conventional therapy failed, doctors are reporting.
Although the doctors are reporting only the first test of the procedure,
and although their findings are considered preliminary, researchers not
connected with the work say the results are encouraging enough to
warrant testing the treatment in more patients with kidney cancer or
certain other types of tumors.
There are 30,000 cases of kidney cancer a year in the United States, a
third of them attributed to smoking, and 12,000 deaths.
The new procedure, a modified version of bone-marrow transplantation,
was developed at the National Heart, Lung and Blood Institute by a team
led by Dr. Richard W. Childs. In a paper to be published tomorrow in
The New England Journal of Medicine, he and his colleagues describe
the first 19 patients they treated, from one to three years ago.
Before treatment, few of the 19 patients were expected to live more than
a year, Dr. Childs said. But nine, all of whom got their treatment more
than a year ago, are still alive, including four in whom all traces of the
cancer have disappeared. In the five others still alive, tumors have shrunk
by more than half.
Eight patients died of their cancer, and two died of complications from
the treatment. The tumors had shrunk in one of these two patients.
"We've taken the worst of the worst kidney-cancer patients, who had no
other treatment option available, and cancers regressed in a majority,"
Dr. Childs said in an interview. "We're making tumors shrink, and making
people live longer."
But, he said, it is impossible to tell how long the remissions will last. "We
don't want to use the word `cure' until it's five years," he said, adding that
cancer patients sometimes relapsed even after 10-year remissions.
All the patients in the study had advanced kidney cancer that had spread
to other organs and that had not improved after conventional treatment
with interleukin-2 or interferon alfa, drugs meant to stimulate the patient's
immune system to fight the tumor.
Those drugs help only about 19 percent of patients. And standard
chemotherapy with drugs meant to kill tumor cells outright is ineffective
against kidney cancer, in part because the kidneys are designed to
remove harmful substances from the body without being affected by
them.
Once kidney cancer has begun to spread, half of patients die in less than
a year.
Bone marrow transplantation, in which cells from a donor are given to a
cancer patient, has not previously been used to treat kidney cancer. It is
most often used to treat leukemia and other cancers that affect the blood
and the immune system.
In those diseases, the patient is given huge doses of chemotherapy and
radiation to kill the cancer. But that treatment also destroys the patient's
immune system and blood- forming cells, and if they are not
reconstituted, the patient will die. So the donor's bone marrow, which
contains stem cells that can create a whole new blood supply and
immune system, is used to "rescue" the patient from the chemotherapy.
In the patients with kidney cancer, Dr. Childs and his colleagues used the
donor cells in a radically different way. Rather than using them to rescue
the patient from chemotherapy, they reasoned that the donor cells
themselves could fight the patient's cancer.
Since chemotherapy does not fight kidney cancer, the patients in the
study were not given big doses of it, or radiation. But they were given
drugs to destroy their immune systems, so that their bodies would not
reject the stem cells that they then received from donors.
The donors were siblings who had matching cell types; patients whose
siblings did not match could not enter the study. The stem cells were
collected from the donors' bloodstream, with no need for the painful
bone punctures used in the past to harvest stem cells from marrow.
The greatest risk of the procedure was that the donor cells would attack
not just the tumors but also the patient's own tissues, in a potentially fatal
reaction called graft-versus- host disease. Two patients did die as a result
of that disorder.
The team gave patients additional drugs to try to prevent the disorder,
but also began withdrawing these drugs as quickly as possible in order to
allow the donors' marrow to fight the cancer cells.
In some cases, it took months for the donor cells to begin working
against the tumors. Dr. Childs said one patient had "explosive" tumor
growth in his lungs 100 days after treatment, and the doctors worried that
he would die. But they gave him some more cells from the donor, and a
month later the tumors had shrunk dramatically. Four months later, they
were gone completely. The patient is now working full time.
Dr. Robert J. Motzer of Memorial Sloan-Kettering Cancer Center in
New York, who was not involved in the study, said: "This is a novel
treatment strategy that has produced encouraging results, in a cancer that
is highly refractory to conventional therapy. But it will have to be
reproduced by other cancer centers. And it has the potential for a high
degree of toxicity." |
