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

To evaluate the influence of blood hemoglobin concentration on the radiosensitivity of acutely reacting normal tissues.

Weekly scores (EORTC/RTOG criteria) for acute reactions of skin and mucosa are available for 60 patients with cancer of the head and neck undergoing a standard conventional radiotherapy. The prognostic significance of blood hemoglobin levels on the development of acute reactions is studied by multivariate analysis (Cox Proportional Hazards Model). Further, the incidence and the time to development of these reactions is looked at in cohorts of patients with different mean blood hemoglobin concentrations during radiotherapy. Patients are therefore classified into a "severely anemic group" (hemoglobin < 11.0 g/100 mL), and into a cohort with a blood hemoglobin value equal or above 11.0 g/100 mL.

Normal tissue scoring and monitoring of blood hemoglobin levels allows for a detailed analysis of possible correlations. A decrease in the mean blood hemoglobin value of 1 g/100 mL 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, respectively) or a mucosa reaction of Grade 3 (RR = 0.8; p = 0.16), independent from the radiation dose, the treatment time and from previous surgery within 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 mL (21%; 19%). Skin and mucosa reactions further tend to occur later in the course of radiation. The observations are not statistically significant and possible reasons will be discussed.

A decreased blood hemoglobin concentration may-perhaps by an impaired tissue oxygenation-reduce the radiosensitivity of normal tissue such as skin and mucosa. However, the data is preliminary and needs further confirmation.