Korean researchers recently found that the percentage of cancerous plasma cells in the bone marrow, measured on day 14 post transplant, may predict disease progression in multiple myeloma patients following high-dose chemotherapy and stem cell transplantation.

However, because their study was small and retrospective in nature, the Korean researchers suggested that further studies be conducted to confirm their findings.

The standard treatment for myeloma patients under the age of 65 years currently consists of high-dose chemotherapy, followed by autologous stem cell transplantation. In this type of transplantation, physicians collect a patient’s stem cells prior to chemotherapy and return these same cells to the individual following treatment.

Although recent advancements have shown that maintenance therapy has improved survival rates after high-dose chemotherapy and transplantation, patients frequently relapse. As a result, researchers are currently investigating the prognostic value of several factors in order to identify what best predicts relapse after transplantation.

In the present study, Korean researchers sought to determine if the percentage of cancerous plasma cells in the marrow at day 14 post transplant could be used as a prognostic factor for outcome.

They retrospectively analyzed data from 39 newly diagnosed myeloma patients who were treated with high-dose chemotherapy and autologous stem cell transplantation between 2003 and 2008. The median patient age at diagnosis was 57 years, and all patients had advanced disease. The median percentage of cancerous plasma cells in the bone marrow was 43 percent at diagnosis.

All of the patients received four 21-day cycles of induction therapy with vincristine ^[1] (Oncovin), doxorubicin ^[2] (Adriamycin), and dexamethasone ^[3] (Decadron). The patients then received preparative therapy with 200 mg/m² of melphalan ^[4] (Alkeran) followed by stem cell transplantation. Patients who did not show disease progression following transplantation received two years of maintenance therapy with alpha-interferon and prednisone ^[5].

At a median follow-up time of 28 months, the median progression-free survival was 29.1 months, and overall survival was 42.1 months.

The researchers found that the percentage of cancerous plasma cells in the bone marrow on day 14 post transplant strongly predicted disease progression in patients. On day 14 post transplant, the median percentage of plasma cells in the bone marrow was 0.7 percent. Patients with at least 2 percent bone marrow plasma cells had significantly shorter progression-free survival and overall survival than patients with less than 2 percent.

The researchers noted that there was no relation between a patient’s bone marrow plasma cell percentage after induction therapy and the bone marrow plasma cell percentage after transplantation. According to the researchers, this finding indicates that the preparative therapy, and not the induction therapy, impacts the post-transplant bone marrow plasma cell percentage.

The researchers suggested that the post-transplant bone marrow plasma cell percentage represents a strong predictive factor for disease progression, regardless of a patient’s disease status prior to transplantation.

For more information, please refer to the study in the Korean Journal of Internal Medicine ^[6] (abstract).