Circulating Cancer Cells Indicate Worse Outcomes Following Transplantation in MM

Circulating Cancer Cells Indicate Worse Outcomes Following Autologous Stem Cell Transplantation in Multiple Myeloma

According to an article recently published in the journal Blood, the presence of cancer cells circulating in the blood is associated with a less favorable prognosis following an autologous stem cell transplant in patients with multiple myeloma.

Multiple myeloma is a cancer of the blood that affects the plasma cells. Plasma cells are an important part of the immune system; they produce antibodies to help fight infection and disease. Multiple Myeloma is characterized by an excess production of abnormal plasma cells. Symptoms include increased risk of bacterial infections and impaired immune responses.

Myeloma may also damage the kidneys and cause osteoporosis, anemia, and an elevated blood calcium level.

In a stem cell transplant, high doses of therapy are used to kill more cancer cells than conventional doses. Unfortunately, the higher doses tend to destroy important hematopoietic stem cells (immature blood cells).

These stem cells mature into the following: red blood cells, which transport oxygen and nutrients to tissues in the body; white blood cells, which help the body fight infection; and platelets, which aid the blood in clotting. Low levels of hematopoietic stem cells caused by high-dose treatment can result in life-threatening conditions.

There are two general types of stem cell transplants: an autologous transplant and an allogeneic transplant. During an autologous transplant, the patients’ own hematopoietic stem cells are collected prior to therapy, frozen, and then re-infused following high-dose treatment.

Although an autologous stem cell transplant is not considered a curative approach in the treatment of multiple myeloma, it allows a significant portion of patients to survive for extended periods of time without additional therapy. However, since the treatment is associated with serious side effects, researchers are trying to determine which patients will gain the most benefit from the procedure; patients who will not achieve significant benefit can thus be identified and offered alternative treatments.

Researchers from the Mayo Clinic recently conducted a clinical trial to evaluate the potential association between cancer cells that are found circulating in the blood directly prior to transplant and outcomes of treatment. They evaluated 246 patients with multiple myeloma who were treated with an autologous stem cell transplant.

Patients with circulating myeloma cells (CMCs) had a worse prognosis than those who did not have detectable circulating myeloma cells.

  • Ninety-five patients had CMCs as detected through a blood test.
  • Complete disappearances of detectable cancer following the transplantation were similar between patients with and without CMCs.
  • Overall survival was 33.2 months following the transplant among patients with CMCs compared with 58.6 months for those without CMCs.
  • Time before cancer progressed was 14.1 months following the transplant among patients with CMCs compared with 22 months for those without CMCs.
  • When combined with cytogenetics (measurement of specific genetic alterations), CMCs were associated with an even greater difference in outcomes: those with established “poor prognosis” cytogenetics plus the presence of CMCs had a median overall survival of only 21.5 months compared with 55 months for those with “good prognosis” cytogenetics and no CMCs.
  • Median time to cancer progression was only 6.5 months among patients with poor-prognosis cytogenetics plus CMCs compared with 22 months for those with good-prognosis cytogenetics and no CMCs.

The researchers concluded that the addition of the presence or absence of CMCs in combination with cytogenetic results provide a powerful predictor for outcomes following autologous stem cell transplants among multiple myeloma patients. Those patients who will not receive a great benefit from an autologous stem cell transplant may wish to pursue alternative treatments.

Patients with multiple myeloma who are planning to undergo an autologous stem cell transplant may wish to speak with their physician regarding their individual risks and benefits of testing for CMCs.

Reference: Dingli D, Nowakowski G, Dispenzieri A, et al. Flow Cytometric Detection of Circulating Myeloma Cells Before Transplantation in Patients with Multiple Myeloma: a Simple Risk Stratification System. Blood.2006; 107: 3384-3388.

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