BONE MARROW TRANSPLANTATION
Although surgery, radiation therapy, and chemotherapy have re-sulted in improved survival rates for cancer patients, many can-cers that initially respond to therapy recur. This is true of hematologic cancers that affect the bone marrow and solid tumor cancers treated with lower doses of antineoplastics to spare the bone marrow from larger, ablative doses of chemotherapy or ra-diation therapy.
The role of bone marrow transplantation (BMT) for malig-nant as well as some nonmalignant diseases continues to grow. Types of BMT based on the source of donor cells include:
· Allogeneic (from a donor other than the patient): either a related donor (ie, family member) or a matched un-related donor (national bone marrow registry, cord blood registry)
· Autologous (from patient)
· Syngeneic (from an identical twin)
The process of obtaining donor cells has evolved over the years. Donor cells can be obtained by the traditional harvesting of large amounts of bone marrow tissue under general anesthesia in the operating room. A newer method, referred to as peripheral blood stem cell transplant (PBSCT), is gaining widespread use. This method of collection uses apheresis of the donor to collect stem cells for reinfusion. It is considered to be a safer and more cost-effective means of collection than the traditional harvesting of marrow.
Allogeneic BMT, used primarily for disease of the bone mar-row, depends on the availability of a human leukocyte antigen– matched donor. This greatly limits the number of transplants pos-sible. An advantage to allogeneic BMT is that the transplanted cells should not be immunologically tolerant of the patient’s ma-lignancy and should cause a lethal graft-versus-disease effect to the malignant cells. The recipient must undergo ablative doses of chemotherapy and possibly total body irradiation to destroy all ex-isting bone marrow and malignant disease. The harvested donor marrow is infused intravenously into the recipient and travels to sites in the body where it produces bone marrow and establishes itself. This establishment of the new bone marrow is known as en-graftment. Once engraftment is complete (2 to 4 weeks, some-times longer), the new bone marrow becomes functional and begins producing red blood cells, WBCs, and platelets.
Before engraftment, patients are at a high risk for infection, sepsis, and bleeding. Side effects of the high-dose chemotherapy and total body irradiation can be acute and chronic. Acute side ef-fects include alopecia, hemorrhagic cystitis, nausea, vomiting, di-arrhea, and severe stomatitis. Chronic side effects include sterility, pulmonary dysfunction, cardiac dysfunction, and liver disease. Pa-tients receive immunosuppressant drugs, such as cyclosporine, tacrolimus (FK 506), or azathioprine (Imuran), to prevent graft-versus-host disease (GVHD). In allogeneic transplant recipients, GVHD occurs when the T lymphocytes from the transplanted donor marrow become activated and mount an immune response against the recipient’s tissues (skin, gastrointestinal tract, liver). T lymphocytes respond in this manner because they view the re-cipient’s tissue as “foreign,” immunologically differing from whatthey recognize as “self” in the donor. GVHD may occur acutely or chronically. The first 100 days or so after allogeneic transplantation are crucial for BMT patients until the immune system and blood-making capacity (hematopoiesis) have recovered sufficiently to pre-vent infection and hemorrhage. Most acute side effects, such as nausea, vomiting, and mucositis, also resolve in the initial 100 days after transplantation. Patients are also at risk for development of ve-nous occlusive disease (VOD), a vascular injury to the liver from the high-dose chemotherapy occurring in the first 100 days or so after BMT. VOD can lead to acute liver failure and death.
Autologous BMT is considered for patients with disease of the bone marrow who do not have a suitable donor for allogeneic BMT and for patients who have healthy bone marrow but require bone marrow–ablative doses of chemotherapy to cure an aggres-sive malignancy. Stem cells are collected from the patient and preserved for reinfusion and, if necessary, treated to kill any malignant cells within the marrow. The patient is treated with ab-lative chemotherapy and, possibly, total body irradiation to erad-icate any remaining tumor. The stem cells are then reinfused and engraft. Until engraftment occurs in the bone marrow sites of the body, the patient is at high risk for infection, sepsis, and bleeding. Acute and chronic toxicities from chemotherapy and radiation therapy may be severe. The risk of VOD is also present after an autologous transplant. No immunosuppressant medications are necessary after autologous BMT because the patient did not re-ceive foreign tissue. A disadvantage of autologous transplantation is the risk that viable tumor cells may remain in the bone marrow despite conditioning regimens (high-dose chemotherapy).
Syngeneic BMT is the least common type of transplantation because it requires an identical sibling for harvest. Syngeneic transplantations result in fewer complications and no marrow re-jection because the donor is an identical tissue match to the re-cipient. The transplantation and collection processes are the same with syngeneic BMT as with allogeneic BMT.
Nursing care of patients undergoing BMT is complex and demands a high level of skill. Transplantation nursing can be extremely re-warding yet extremely stressful. The success of BMT is greatly in-fluenced by nursing care throughout the transplantation process.
All patients must undergo extensive pretransplantation evalua-tions to assess the current clinical status of the disease. Nutritional assessments, extensive physical examinations and organ function tests, and psychological evaluations are conducted. Blood work includes assessing past antigen exposure (for example, to hepatitis virus, cytomegalovirus, herpes simplex virus, HIV, and syphilis). The patient’s social support systems and financial and insurance resources are also evaluated. Informed consent and patient teach-ing about the procedure and pretransplantation and posttrans-plantation care are vital.
Skilled nursing care is required during the treatment phase of BMT when high-dose chemotherapy (conditioning regimen) and total body irradiation are administered. The acute toxicities of nausea, diarrhea, mucositis, and hemorrhagic cystitis require close monitoring and constant attention by the nurse.
Nursing management during the bone marrow or stem cell in-fusions consists of monitoring the patient’s vital signs and bloodoxygen saturation; assessing for adverse effects, such as fever, chills, shortness of breath, chest pain, cutaneous reactions, nausea, vom-iting, hypotension or hypertension, tachycardia, anxiety, and taste changes; and providing ongoing support and patient teaching.
Throughout the period of bone marrow aplasia until engraft-ment of the new marrow occurs, patients are at high risk for dying of sepsis and bleeding. Patients require support with blood prod-ucts and hemopoietic growth factors. Potential infection may be bacterial, viral, fungal, or protozoan in origin. Renal complica-tions arise from the nephrotoxic chemotherapy agents used in the conditioning regimen or those used to treat infection (ampho-tericin B, aminoglycosides). Tumor lysis syndrome and acute tubular necrosis are also risks after BMT.
GVHD requires skillful nursing assessment to detect early ef-fects on the skin, liver, and gastrointestinal tract. VOD resulting from the conditioning regimens used in BMT can result in fluid retention, jaundice, abdominal pain, ascites, tender and enlarged liver, and encephalopathy. Pulmonary complications, such as pulmonary edema, interstitial pneumonia, and other pneumo-nias, often complicate the recovery after BMT.
Ongoing nursing assessment in follow-up visits is essential to de-tect late effects of therapy in BMT patients. Late complications are those that occur 100 days or more after BMT. Late effects in-clude infections, such as varicella zoster infection, restrictive pul-monary abnormalities, and recurrent pneumonias. Sterility often results. Chronic GVHD involves the skin, liver, intestine, esoph-agus, eye, lungs, joints, and vaginal mucosa. Cataracts may also develop after total body irradiation.
Psychosocial assessments by nursing staff must be ongoing. In addition to the stressors affecting patients at each phase of the transplantation experience, marrow donors and family members also have psychosocial needs that must be addressed.
Donors commonly experience mood alterations, decreased self-esteem, and guilt from feelings of failure if the transplantation fails. Family members must be educated and supported to reduce anxiety and promote coping during this difficult time. Family members must also be assisted to maintain realistic expectations of themselves as well as of the patient.
As BMT becomes more prevalent, many moral and ethical issues become apparent, including those related to informed consent, allocation of resources, and quality of life.