In 1991, an estimated 1,000 U.S. patients underwent a peripheral stem cell harvest tPSCH) and transplant. PSCHs have been used instead of or in addition to autologous bone marrow harvests when transplanting patients with acute myelogenous leukemia (AML, also called acute non-lymphocytic leukemia or ANLL), acute lymphocytic leukemia (ALL), Hodgkin's disease, non-Hodgkin's lymphoma, brain tumors, breast cancer, ovarian cancer, multiple myeloma, small cell lung cancer, testicular cancer and neuroblastoma.
More than 58 BMT centers in the U.S. now perform peripheral stem cell harvests and transplants and that number is growing. Peripheral stem cell transplants differ from autologous BMTs only in the method of collecting "stem cells," the cells that are reinfused into the patient during the transplant.
Mature blood cells evolve from "mother" cells called stem cells. The most primitive of these is the pluripotent stem cell that is believed to be the origin of all blood cells.
Pluripotent stem cells differ from other blood cells in that they are capable both of unlimited self-renewal and differentiation. Self-renewal means the cell is able to reproduce another cell identical to itself, thus maintaining a steady number of these types of cells in the body. Differentiation means the cell is capable of generating one or more subsets of more mature cells that eventually evolve into either erythrocytes, neu- trophils, eosinophils, basophils, lymphocytes, monocytes or platelets.
When physicians harvest bone marrow for use in a transplant, it is the stem cells they are seeking. Stem cells resemble medium sized white blood cells. It has been estimated that less than one in 100,000 cells in the bone marrow are stem cells.
When stem cells are infused into a patient's bloodstream, they will migrate to the interior of certain bones, set up housekeeping or "colonize" and begin producing immature cells called "committed progenitors." These committed progenitors produce colonies of cells that eventually mature into red blood cells, white blood cells, or platelets.
Although the largest concentration of stem cells in the body is found in the bone marrow, stem cells also can be found in the bloodstream or l"peripheral blood." The concentration of stem cells in the bloodstream is normally 1/100 of that in bone marrow. Extracting stem cells from the peripheral blood is called a "peripheral stem cell harvest" or PSCH.
The process used to extract stem cells from the bloodstream is similar to the process used to collect platelets from platelet donors. Patients are connected to a cell separation machine or "apheresis" device. A needle is inserted in each arm and blood is withdrawn from one arm and circulated through the machine to extract the stem cells. The remaining cells are returned to the patient through a needle in the opposite arm. Alternatively, the blood may be withdrawn and returned to the patient through a catheter.
The PSCH is painless. Patients occasionally experience lightheadedness, coldness, numbness around the lips, or cramping in the hands during the harvest.
Typically, several two-to-six-hour sessions are required to collect sufficient stem cells from the bloodstream for transplantation. If drugs called "growth factors" or "colony-stimulating factors" (e.g., granulocyte-colony stimulating factor, G-CSF, or granulocyte- macrophage colony stimulating factor, GM-CSF) are given before and during the period of time when peripheral stem cells are being harvested, the number and duration of the sessions may be less. The procedure is usually performed on an outpatient basis over a one- to two-week period. After each session, the stem cells are frozen using a process called cryopreservation.
REASONS FOR PSCHSPhysicians may recommend a PSCH for a variety of reasons. Sometimes PSCHs are used to augment the stem cells collected from a bone marrow harvest. In other cases, a patient's bone marrow may be contaminated by cancerous cells and a PSCH may be used in lieu of a bone marrow harvest in the hope that the peripheral blood stem cells have not been similarlycontaminated. Prior radiation to the pelvic area or chemotherapy can also reduce the number of stem cells available via a bone marrow harvest, making a PSCH necessary.
A PSCH may provide patients whose bone marrow is unsuitable for harvesting their only opportunity to undergo an autologous transplant. PSCH also allows collection of stem cells without the use of general anesthesia, involves little or no discomfort and can be done on an outpatient basis. Collection of stem cells through a PSCH, however, requires many days or even weeks while bone marrow harvests can be completed in a single two-hour session in an operating room. The difference in time required to harvest stem cells from the peripheral blood vs. the bone marrow may be critical for patients whose disease is progressing rapidly.
PSCHs also require more laboratory processing time since each sample must be frozen separately. This may increase costs and/or strain laboratory resources at some centers. In a 1992 BMT Newsletter survey of 58 BMT centers performing PSCHs, 38 percent said PSCHs cost more than bone marrow harvests to obtain sufficient stem cells for transplantation. Thirty-one percent said the difference in cost was greater than 20 percent.
Although stem cells derived from the bloodstream can be successfully used in an autologous transplant, they do not appear to be exactly the same as stem cells derived from bone marrow. Whether the stem cells used in a transplant are collected from the bone marrow or peripheral blood, however, does not appear to affect the incidence of full recovery or rate of long term survival. Ultimately, the success of an autologous BMT depends less on the source of stem cells used in the transplant than on the effectiveness of the chemotherapy and/or radiation administered to destroy the diseased cells before the transplant.
Forty-six-year-old Thelda DeLanghe of Bremen, Indiana has lots to be proud of. Less than a year after undergoing a peripheral stem cell harvest and transplant to treat her breast cancer, she's back to work full time, enjoying her first grandchild, Erin, and helping others who face the prospect of a bone marrow transplant.
For DeLanghe, the road to recovery wasn't easy. At first, Blue Cross/Blue Shield refused to pay for her treatment. "When the women at the school where I work heard about the denial they were very concerned," said DeLanghe. "They knew the same thing could happen to them." With the help of a letter writing campaign orchestrated by school employees and neighbors, the intervention of Indiana State Representative Kent Adams and former Governor Otis Bowen, and the work of an attorney, Blue Cross/Blue Shield finally relented and agreed to pay.
For eight consecutive days in April 1991, DeLanghe and her husband Larry drove the five-hour round trip to Chicago and back for the peripheral stem cell harvest. "The nurses were real angels of mercy," said DeLanghe. "One even fixed us home cooked meals and brought movies to keep us entertained during the harvest."
Meanwhile, friends and neighbors in Bremen held a dance and other fundraisers to help with expenses. Larry, a truck driver, had been laid off since Christmas and turned down the chance to return to work in the spring so he could be with Thelda during treatment. In June, 28 days after being admitted to the hospital for the transplant, Thelda arrived home. "The support I got from family, friends, and the community
(Page 51)
while I was hospitalized was unreal," said DeLanghe. "My 70 year-old parents, my son and his friends, and other family members all made the long drive to visit me. The school principal and teachers came to donate platelets. When my daugh ter, who was five months pregnant visited, I was really inspired to get well. I wanted to see my first grandchild." Thelda was back to work full time at the end of July. "The first week was hard-I barely had the energy to eat and go to bed when I got home. But it got better with each day that passed."
Before long, Thelda had a chance to repay the kindness she experienced during her treatment. "A 64 year-old man from a nearby community who buys cars in Bremen kept following my progress and asking about me," she said. "I finally found out he was going to have a peripheral stem cell transplant for lymphoma in Indianapolis, so I wrote to give him encouragement." They met for the first time a month ago and have been giving each other support ever since. "When you give a little of yourself, you get a lot back in return."
"Deciding to have a transplant is not easy," says Thelda. "At first you feel like you're on a roller coaster. Everything's out of control. Your life's in the hands of strangers and there's a tremendous fear of the unknown. Sometimes my mind was a blank and other times I wondered 'What am I doing?' But then I thought 'What's the alternative? If I'm going to die, I want to go down fighting.' I wasn't ready to give in to the disease. I feel special to be a survivor."
Click for "Bone Marrow Transplants" table of contents
This document was created by NYSERNet, Inc. through a grant funded by the New York State Science and Technology Foundation as part of the Breast Cancer Infomation Clearinghouse.