High-dose chemotherapy with autologous peripheral stem cell support is the treatment of choice for patients with non-Hodgkin’s lymphoma (NHL) who fail initial chemotherapy treatment. However, as many as 50% of patients treated with high-dose chemotherapy will still experience cancer recurrence. There has been concern that some cancer recurrences may be caused by lymphoma (cancerous lymphocytes) cells collected in the blood stem cell collection and subsequently infused into the patient after high-dose chemotherapy.
The standard treatment of patients with NHL who fail to respond to initial chemotherapy is treatment with high-dose chemotherapy followed by autologous stem cell transplantation. Chemotherapy targets and kills rapidly dividing cells, such as cancer cells and high-dose chemotherapy kills more cancer cells than lower dose conventional chemotherapy. Unfortunately, high-dose chemotherapy also kills more normal cells, especially the blood producing stem cells in the bone marrow.
Stem cells are immature cells produced in the bone marrow (spongy material inside large bones). Stem cells eventually become either red blood cells, which provide Oxygen to tissues, white blood cells, which fight infection, or platelets, which aid in blood clotting. When high-dose chemotherapy is destroying cancer cells it is also killing the bone marrow stem cells. When bone marrow is destroyed, stem cell stores are depleted leading to low levels of circulating blood cells. When these cells reach critically low levels, complications such as anemia, bleeding and infection can occur. Thus, it is imperative to restore stem cell levels as quickly as possible. During an autologous stem cell transplant, the patient’s own stem cells are collected from circulating blood before chemotherapy treatment, frozen, and infused back into the patient after treatment to “rescue” the bone marrow.
A concern of some doctors is that lymphoma cells may be collected along with stem cells and later re-infused back into the patient. There is evidence that infusion of lymphoma cells may cause some cancer recurrences following stem cell transplant. Researchers have been evaluating different techniques for killing or “purging” cancer cells from the collection of blood used for stem cell transplant. A recent new treatment approach using a biological agent, Rituxan™ has shown promising results in killing lymphocytes in patients with NHL. Rituxan™ is a monoclonal antibody that binds to proteins on the surface of B-lymphocytes. This binding stimulates the immune system to attack and kill the cancerous B-cells. Since most lymphomas involve only B-cells, Rituxan™ targets only cancer cells, unlike chemotherapy or radiation which cannot differentiate between cancer cells or healthy cells in the body.
Physicians in Italy have presented evidence that chemotherapy and Rituxan™ administered before the collection of stem cells reduces or eliminates lymphoma cells in the stem cell collection. Fifteen patients with NHL were treated with either chemotherapy and Rituxan™ or chemotherapy alone before the collection of stem cells. Ninety three percent of patients treated with chemotherapy plus Rituxan™ had no lymphoma cells in their stem cell collection. In comparison, only forty percent of patients treated with chemotherapy alone had no detectable lymphoma cells in their stem cell collection. Importantly, all patients receiving chemotherapy plus Rituxan™ achieved a complete clinical remission (no detectable cancer cells were found in their body).
This study provides evidence that lymphoma-free stem cell collections can be obtained if chemotherapy and Rituxan™ are administered to a patient before stem cell collection. The high response rate also shows the effectiveness of chemotherapy and Rituxan™ as treatment for selected B-cell NHL being treated with autologous stem cell transplantation. Persons with B-cell NHL may wish to talk to their physician about the risks and benefits of participating in ongoing clinical trials using Rituxan™ or other monoclonal antibodies to remove lymphoma cells from the stem cell collection. Two sources of information on ongoing clinical trials that can be discussed with a doctor include comprehensive, easy to use clinical trials listing services provided by the National Cancer Institute (
eCancerTrials.com. eCancerTrials.com also performs personalized clinical trial searches on behalf of patients. (
Blood, Vol 96, No 3, pp 964-869, 2000)
Copyright © 2018 CancerConnect. All Rights Reserved.