Patients at increased risk for late engraftment after transplantation: a novel method for their identification

The time to platelet engraftment (platelets greater than 50 x 10(9)/l for 3 successive days without transfusions) is a major endpoint in treatment regimens of high dose chemotherapy and autologous stem cell rescue. A number of transplanted patients die before recovery of platelets. To include such patients appropriately in an analysis to identify prognostic factors for engraftment, a proportional odds model was employed. The outcome measure was a categorization of patients into four levels based on time to engraftment: early (0-40 days), intermediate (41-70 days), late (greater than 70 days) or died without engraftment. Of 45 women with advanced breast cancer who underwent high dose chemotherapy and autologous transplantation, there were: 10 early, 11 intermediate and eight late engrafters and 16 who died before platelet engraftment. Based on the proportional odds model applied to these data, four significant and independent prognostic factors for later or non-engraftment were revealed: lower numbers of mononuclear cells/kg harvested (p = 0.002), lower serum albumin level (p = 0.003), prior cisplatin chemotherapy (p = 0.006), and the existence of bone marrow malignancy (p = 0.025).