Regimen-related toxicity in patients undergoing bone marrow transplantation.

Bone marrow transplantation is associated with significant morbidity and mortality, some of which is due to high-dose chemoradiotherapy. In order to quantitate toxicity that was felt to be due to the preparative regimen (termed regimen-related toxicity [RRT]), a system was developed in which toxicities were graded from 0 (none) to 4 (fatal). One hundred ninety-five patients who underwent marrow transplantation for leukemia were studied retrospectively to determine whether toxicities that were clinically felt to be due to the preparative regimen were influenced by other factors such as disease status, graft-versus-host disease (GVHD) prophylaxis, and allogenicity. All patients developed grade I toxicity in at least one organ, and 30 developed grades III-IV (life-threatening or fatal) RRT. RRT was more common in relapsed patients v remission patients (P = .04), in those receiving 15.75 Gy total body irradiation (TBI) v 12.0 Gy TBI (P = .028), and in those receiving allogeneic marrow v autologous marrow (P = .0029). Autologous marrow recipients did not develop grades III-IV toxicity in this study. A multivariate analysis controlling for autologous marrow grafting showed that the dose of TBI was the only statistically significant predictor of grades III-IV RRT. Those patients who developed grade III RRT were unlikely to survive 100 days from transplant, though not all deaths could be attributed to RRT. Patients who developed grade II toxicity in three or more organs were more likely to die within 100 days than those developing grade II toxicity in two or less organs (P = .0027). This system was generally able to distinguish RRT from other toxicities observed in marrow recipients.