Blood hemoglobin level may affect radiosensitivity - Preliminary results on acutely reacting normal tissues

Purpose: To evaluate the influence of blood hemoglobin concentration on the radiosensitivity of acutely reacting normal tissues, Methods and Materials: Weekly scores (EORTC/RTOG criteria) for acute reacti ons of skin and mucosa are available for 60 patients with cancer of the hea d and neck undergoing a standard conventional radiotherapy. The prognostic significance of blood hemoglobin levels on the development of acute reactio ns is studied by multivariate analysis (Cox Proportional Hazards Model). Fu rther, the incidence and the time to development of these reactions is look ed at in cohorts of patients with different mean blood hemoglobin concentra tions during radiotherapy. Patients are therefore classified into a "severe ly anemic group" (hemoglobin < 11.0 g/100 mt), and into a cohort with a blo od hemoglobin value equal or above 11.0 g/100 mt. Results: Normal tissue scoring and monitoring of blood hemoglobin levels al lows for a detailed analysis of possible correlations, A decrease in the me an blood hemoglobin value of 1 g/100 mt predicts a reduced risk to develop a skin reaction of Grade 2 or 3 (RR = 0.9; p = 0.08; RR = 0.8; p = 0.26, re spectively) or a mucosa reaction of Grade 3 (RR = 0.8; p = 0.16), independe nt from the radiation dose, the treatment time and from previous surgery wi thin the radiation volume (multivariate analysis). Likewise, patients with severe anemia develop grade 3 mucositis or dermatitis less often (0%; 13%) as compared to those with blood hemoglobin concentrations equal or above 11 .0 g/100 mt (21%; 19%), Skin and mucosa reactions further tend to occur lat er in the course of radiation. The observations are not statistically signi ficant and possible reasons will be discussed. Conclusions: A decreased blood hemoglobin concentration may-perhaps by an i mpaired tissue oxygenation-reduce the radiosensitivity of normal tissue suc h as skin and mucosa, However, the data is preliminary and needs further co nfirmation, (C) 2000 Elsevier Science Inc.