Radiotherapy-associated neutropenia and thrombocytopenia: analysis of risk
factors and development of a predictive model
M Mac Manus, K Lamborn, W Khan, A Varghese, L Graef and S Knox
Department of Radiation Oncology, Stanford University, CA 94305-5105, USA.
Risk factors for unscheduled interruptions in radiotherapy courses
completed between June 1989 and August 1995, lasting > or = 2 days, and
associated with World Health Organization grade III-IV neutropenia or
thrombocytopenia were studied retrospectively. A group of controls was
randomly selected. Potential risk factors for myelosuppression were
analyzed using univariate and multivariate analyses. The most important
risk factors for treatment interruption with thrombocytopenia were
concurrent chemotherapy (odds ratio [OR], 45.5; P < .001), increasing
percentage of marrow irradiated (OR, 4.1 for each 20%; P < .001), and
brain metastases (OR, 7.3; P = .01). Other significant (P < .05) factors
were leukemia/lymphoma, bone or bone marrow metastases, and prior
chemotherapy. The most important risk factors for treatment interruptions
with neutropenia were concurrent chemotherapy (OR, 42.1; P < .001) and
increasing percentage of marrow irradiated (OR, 3.3 for each 20%; P <
.001). Similarly, the most important risk factors for treatment
interruptions with both thrombocytopenia and neutropenia were concurrent
chemotherapy (OR, 48.6; P < .001) and increasing percentage of marrow
irradiated (OR, 3.9 for each 20%; P < .001). Other significant (P <
.05) factors in these groups were bone marrow or brain metastases and
previous chemotherapy. These data were used to create a model, assigning
patients to groups at high, intermediate, or low risk for treatment
interruption with thrombocytopenia. High-risk patients may be candidates
for clinical trials of a platelet growth factor.
Volume 89,
Issue 7,
pp. 2303-2310,
04/01/1997
Copyright © 1997 by The American Society of Hematology
