Persons with the human immunodeficiency virus (HIV) have a much higher incidence of non-Hodgkin’s lymphoma (NHL) compared to persons without the virus. Because HIV weakens the immune (infection fighting) system of the body, NHL treatment is not aggressive and is associated with a poor prognosis. Recently, however, researchers have reported the successful treatment of HIV related NHL with autologous stem cell transplantation and anti-viral therapy.
Non-Hodgkin’s lymphoma is a cancer of the lymph tissue, which is part of the immune system in the body. Lymph tissue is present in lymph nodes, lymph vessels and bone marrow, which exist throughout the body. It is also present in organs such as the thymus, tonsils, and spleen. One of the main cells in the lymph system is the lymphocyte, of which there are two types: B and T-cells. Each of these cells has a very specific function in aiding the body to fight infection. The large majority of NHL cases involve cancer of the B- lymphocytes, characterized by the excessive multiplication of these atypical cells. These cancerous cells can crowd lymph tissue causing suppression of normal formation and function of other cells normally found in this tissue. Because lymphocytes can travel virtually anywhere in the body through blood or lymph fluid, lymphomas can occur in sites other than lymph tissue, such as the gastrointestinal tract or the brain.
Patients with NHL who fail to respond to initial chemotherapy or have a recurrence (return of cancer) may be treated with additional high-dose chemotherapy followed by autologous stem cell transplantation (SCT). Chemotherapy targets and kills rapidly dividing cells, such as cancer cells. Although chemotherapy is effective at killing cancer cells, treatment does not differentiate between cancer cells and healthy cells. 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. The treatment strategy utilizing stem cell transplant is an attempt to restore the blood producing stem cells after high-dose chemotherapy has reduced them to dangerously low levels. Stem cells are immature cells produced in the bone marrow (spongy material inside 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 cells 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 which may result in death. Thus, it is imperative to restore stem cell levels as quickly as possible, particularly in patients with HIV whose immune system is already compromised. In autologous (self) SCT, the patient’s own stem cells are collected before chemotherapy treatment, frozen, and infused back into the patient after treatment to “rescue” the bone marrow.
There has been concern regarding autologous SCT in HIV patients because the stem cells to be re-infused would contain HIV. However, researchers recently reported the effectiveness of anti-viral therapy with high-dose chemotherapy and autologous SCT for the treatment of two patients with HIV-related NHL. Prior to the collection of stem cells, the patients received anti-viral treatment to kill HIV infected cells in order to obtain a collection of stem cells that did not contain the virus. After collection, these patients received high-dose chemotherapy and further anti-viral treatment. Both patients had a rapid recovery after the high-dose chemotherapy and SCT and remained in remission an average of 2 years. These remissions are longer than one would expect from conventional dose treatment. This preliminary report indicates that anti-viral treatment with high-dose chemotherapy and autologous SCT is feasible in selected patients with HIV-related NHL. This strategy represents an alternative treatment option that can be investigated further for patients with this disease.
Patients with HIV-related NHL may wish to talk to their doctor about high-dose chemotherapy treatment with autologous stem cell support or other promising, new treatments. Two sources of information on ongoing clinical trials that can also be discussed with a doctor include comprehensive, easy to use clinical trials listing services provided by the National Cancer Institute (cancer.gov) and eCancerTrials.com. eCancerTrials.com also performs personalized clinical trial searches on behalf of patients (Cancer, Vol 89, No 3, pp 680-689, 2000).
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