Some time this week Childrens Hospital of Orange County will perform the county's first bone marrow transplant. For the 2 1/2-year-old patient, it will mean a much better shot at emerging the winner in her bout with neuroblastoma, a form of malignant cancer that started at the base of her brain and has since spread to her bones and lungs.
Dr. Mitchell Cairo, director of cancer research at the hospital, said although the Santa Ana girl is presently in remission--she shows no overt symptoms of the disease--studies indicate that only one of five neuroblastoma victims remain this way. "The rest relapse and die," he said.
For the child, whose parents have requested anonymity, the transplant will increase her chances for life to 50-50.
The first human bone marrow transplant was attempted in 1939, but it has only been in the past decade that the treatment has become an important means of treating cancer patients. With this week's transplant, Childrens Hospital will become the fourth hospital in the Los Angeles and Orange County area performing this treatment, Cairo said.
Transplants are considered when other types of treatment, such as chemotherapy, fail and the transplant is the only hope for a cure.
Patients undergoing the transplant are given very high doses of anti-cancer drugs and total-body radiation over a span of three to seven days.
The drug therapy and radiation kill the cancer cells, but they also destroy the patient's bone marrow, the spongy tissue inside bones which manufactures components of the blood--red cells, white cells and platelets--and with it the patient's immune system.
But because the patient is going to be receiving a transplant to replace the destroyed marrow, it "allows us to destroy cancer cells that are sensitive to radiation, but only in extremely high doses," Cairo said.
Marrow is then transfused into the patients' blood stream to replace the lost marrow, although it takes three to four weeks before the immune system is strong enough for the patient to venture outside of a sterile environment.
Early transplants failed because patients' bodies would reject transfusions from donors whose marrow was not almost identical to theirs. Better matching techniques were developed in the 1960s, and, today, most marrow for transplantation is harvested from siblings of the patient--a procedure called an allogenic transplant.
Childrens Hospital this week will use a newer, more successful technique called an autologous transplant, where the donor is the patient herself.
Three months ago, the girl was placed under general anesthesia, and a long needle was used to extract a small amount of marrow from a bone in her pelvic area. The procedure was repeated about 30 times in the front and back of her pelvic area before enough marrow was extracted, Cairo said.
About six cubic centimeters of marrow per pound of body weight is the standard amount taken, an amount Cairo says is small enough that the body does not notice it.
The marrow is sterilized, then frozen in liquid nitrogen until it is needed.
Autologous transplants solve two problems, according to Cairo. One, there is no need to find a matching donor--otherwise a problem, since only about 35% of siblings are closely enough matched for a transplant. And two, there is no problem with the patient's marrow rejecting the transplanted marrow or the transplanted marrow rejecting the patient's. About 30% of allogeneic transplants fail for this reason, Cairo said.
The critical period for autologous transplants is the three weeks after the transfusion when patients' immune systems are weak, leaving them open to infection because of lack of white cells or bleeding complications because their platelet count is low.
To reduce the chances of a life-threatening infection, patients at the Childrens Hospital's bone marrow transplant unit will be kept in one of two rooms that are specially sterilized, Cairo said.
Everything in the room is sterilized from the toys to the food. The air is sterilized using a filter system and between the room and the hallway is a waiting room where doctors and visitors wash themselves before entering.
The main disadvantage of autologous transplants is that the marrow from a self-donor must be extracted while he or she is in remission, a time when parents and patients are reluctant to think about the possibility of a relapse, Cairo said.
Another Orange County family decided not to take the chance that marrow would not be available if needed. Susie Buchan's 7-year-old son, Kent, has been in remission since he started chemotherapy three years ago for a lymphoma tumor behind his right eye. Five months ago, when he was deemed well enough to be taken off the medication, Buchan and her husband, Leonard, asked Cairo to harvest a reserve of bone marrow from Kent in case he relapses.
"It's like money in the bank for us," said Buchan, who lives in Placentia. "If Kent ever comes off this remission--which I don't think he will--after no matter how many years, it will be here for him."
"Kent has been through so much, my husband and I decided that whatever precaution we could take to save Kent's life, we would take," she added.
The precaution did not seem to faze Kent. Two days after the extraction, the blond boy was out swinging a bat on a baseball diamond with the rest of his Little League teammates.
Cairo said 40 cancer patients currently have marrow frozen in his laboratory.