A new study by researchers at The Medical College of Wisconsin Cancer Center Milwaukee, has found that African Americans and whites have identical survival rates after undergoing autologous (self donor) bone marrow transplant treatment for a common cancer of the bone marrow (multiple myeloma). However, in a previous study the researchers showed that African Americans were only half as likely as whites to actually receive a bone marrow transplant, the well-established life-prolonging treatment for the disease.
The results of their study were presented today (Dec. 8) at the 50th Annual meeting of the American Society of Hematology in San Francisco by lead researcher, Parameswaran Hari, M.D., assistant professor of medicine in neoplastic diseases. Dr. Hari who practices at Froedtert Hospital, a major teaching affiliate of the College.
Over 15,000 Americans are diagnosed with multiple myeloma each year. The incidence of multiple myeloma in African Americans is twice that of whites and African Americans are twice as likely to die from this disease. It is also the most common diagnosis for which bone a marrow transplant, also known as hematopoietic stem cell transplant, is performed.
Dr. Hari and a research team from the Center for International Blood and Marrow Transplant Research (CIBMTR) compared the estimated rate of transplants and incidence rate of myeloma from SEER data (Surveillance Epidemiology and End Results, a program of the National Cancer Institute). They concluded that African Americans are less likely to undergo transplants.
Further, a review of data reported to the CIBMTR showed no significant difference between the races in survival, progression-free survival, non-relapse mortality or relapse after transplantation. (CIBMTR, headquartered at the Medical College, is the world's largest clinical database of related blood and marrow transplants with the goal of increasing scientific knowledge of blood and marrow transplantation through research).
"This suggests that equal treatment results in equal outcomes," says Dr. Hari. "More study is needed to correct the causes of this imbalance in transplant rates especially since the transplant treatment itself is equally efficacious but less likely to be applied in African Americans. We need to now find out more about the patients who are being excluded from this procedure and why.
"African Americans also received transplants later in the course of their disease, on average, more than a year after diagnosis." says Dr. Hari.
The researchers also found that African Americans receiving autologous transplants were generally younger, and more likely to be both female and to have other illnesses such as obesity, diabetes and high blood pressure, compared to their white counterparts. "However, the outcomes were very similar, in terms of survival, survival without disease progression, relapse of myeloma and treatment-related mortality.
Dr. Hari believes that these subtle differences between patient groups at baseline may hold clues to why African Americans are less likely to get to transplantation.
Co authors on the study with Dr. Hari are Navneet S. Majhail, M.D., M.S., University of Minnesota; Anna Hassebroek, MPH, statistician, CIBMTR-National Marrow Donor Program, Minneapolis campus; Mei-Jie Zhang, Ph.D., biostatistician, Medical College; Fareeha Siddiqui, M.D., of St. Anne's Hospital in Fall River, Mass.; and Paulette Mehta, M.D., of the University of Arkansas for Medical Sciences, Central Arkansas Veterans Healthcare Systems, Little Rock, Ark.