An experimental treatment for advanced kidney cancer using blood cells donated by a sibling completely or partially reversed the often lethal disease, doctors at the National Institute of Health are reporting.
Cancer researchers already are exploring whether this new technique may open up another avenue for treating kidney tumors, as well as other forms of cancer.
The small study involved only 19 patients with kidney cancer that had spread, or metastasized, throughout their body, a stage where only 20 percent of patients are expected to survive beyond a year.
In the study, which will be published in Thursday’s New England Journal of Medicine, nearly 50 percent of the patients who received the treatment survived the year, with 10 showing improvement. In three cases the tumors completely regressed.
“We are very encouraged by the early high response rate in our first group of patients treated,” said lead investigator Dr. Richard Childs of the National Heart, Lung and Blood Institute’s hematology unit in Bethesda, Maryland.
Who is at Risk? Kidney cancer affects 31,000 Americans annually, killing 11,900 of them, according to the American Cancer Society. Those at special risk include males, smokers and those over the age of 50.
Kidney cancer warning signs include blood in the urine, lower back pain or a lump in the belly. When the disease is caught early and can be surgically removed, it has a fairly good prognosis.
But for patients like those in the study with advanced renal cell carcinoma, or kidney cancer which has spread throughout the body, the disease is usually fatal within a year.
Chemotherapy is often ineffective on kidney cancer, while newer drugs such as immunotherapies that stimulate the immune system to fight off cancer only seem to work in a small number of patients.
This new work is important because it may have uncovered an additional approach for the treatment of cancer, experts say.
“The results certainly suggest a whole new application for a novel therapy,” says Dr. David Porter, director of bone marrow transplantation at the University of Pennsylvania Medical Center, who is conducting similar work.
How Treatment Works
The treatment involves first suppressing the patients’ own immune systems, to allow them to accept transplanted donor stem cells from their siblings’ blood.
The donor blood cells are then transplanted into the patients’ veins, and allowed over the next few months to develop into immune cells known as lymphocytes that have the ability to fight against the cancerous tumor cells. This process is known as the graft vs. tumor effect.
“Picture the stem cells seeding in the [bone] marrow after transplant and generating an entirely new immune system,” explains Stephen Bartelmez, an assistant professor of pathobiology at the University of Washington in Seattle. “The donor T-lymphocytes then recognize the cancer cells as foreign and snuff them out.”
Doctors have previously used this technique in fighting cancers such as leukemia, caused by cancerous blood-producing cells. But they say this is the first time it has been shown to be effective against a “solid” cancer tumor, such as the ones formed in the kidney, as well as other organs like the breast and the prostate.
Effective on Other Cancers?
“This is provocative, fairly compelling data that bone-marrow transplantation can induce an effect against a solid tumor type,” says Dr. George Daley, a leukemia specialist at the Massachusetts Institute of Technology’s Whitehead Institute in Cambridge, Mass.
Researchers at several medical centers around the country already are conducting similar research on stem-cell transplants for kidney as well as other solid cancers.
“One problem,” notes Dr. Walter Stadler, an oncologist conducting such research at the University of Chicago. “is that this [requires] a very highly selective patient population — their disease had to be progressing slowly enough that they could wait the necessary times, usually months, to experience a response.”
And many experts warned the work is still preliminary and should not be considered an option for patients with other cancer types.
“Right now, we don’t know the implication for other solid tumors,” says Dr. John Barrett, of the NIH, an investigator on the study. “We are evaluating the approach.”
The kidney was specifically chosen for this treatment because it has been shown in past studies to respond well to immunotherapy treatment, Stadler says. But other forms of cancers that do not respond to immunotherapy may also not respond to stem cell replacement.
Still a Risky Procedure
And the treatment does have potential risks: two of the patients in the NIH study died from transplant complications. Half suffered from graft vs. host disease, when donor cells turned against the patient’s own body. Two of those with an initial response have since had a relapse. And eight of the patients in the study died as their diseases progressed.
“Whether this will be applicable on a general basis is unknown,” notes Len Zwelling, a researcher at the University of Texas Anderson Cancer Center. “This is expensive and obviously risky.”