Anemia and the requirement for transfusions are major clinical problems in patients with MDS. Red blood cell (RBC) transfusion requirement has been incorporated in several “scoring systems” allowing clinicians to predict overall survival and determine best treatment modalities for their patients.
RBC transfusion dependence could contribute to poor prognostic risk by several mechanisms. It could simply be an indicator of poor bone marrow function as part of the presenting feature of the patient’s MDS. While necessary, transfusions themselves could pose a risk to the patient, for example due to immunization against donor cells or iron overload from transfused red cells.
The group of R.A. Wells at the Odette Cancer Centre at Sunnybrook Health Sciences Centre in Toronto, Canada, devised a new assessment tool, “Initial Transfusion Intensity” (ITI), to dissect the role of transfusion dependence in patients newly diagnosed with MDS. They defined ITI simply as the number of RBC units transfused in the 4 weeks following the initial transfusion. The 4-week cutoff was determined as the median interval between the first and second transfusion a patient received based on a hemoglobin cutoff of 8g/dL. They divided their 52 patients into 2 groups with an ITI < median and an ITI ≥ median (4 weeks) and assessed whether ITI could accurately categorize patients as higher versus lower risk disease.
Patients who had higher ITI had higher transfusion dependence throughout their course and indeed had shorter overall survival than those patients who did not require a RBC transfusion within 4 weeks of their first transfusion. This prediction held true even in patients who were otherwise classified as having lower risk disease, e.g. by the revised International Prognostic Scoring System (IPSS-R).
This study was performed retrospectively at a single institution, but the promising results have led to a larger ongoing study at several Canadian Medical Centers. If confirmed, simple calculation of the initial transfusion intensity, a measure easily applicable in any office or clinic setting, could prompt new therapeutic studies and intensified treatment for those patients classified as higher risk by ITI, independent of their IPSS classification. Incorporation of the ITI into the IPSS and other scoring systems could allow more accurate assessment of disease severity and improve outcomes.