Haematological toxicity in adult patients receiving craniospinal irradiation--indication of a dose-bath effect.

BACKGROUND AND PURPOSE

The purpose of this study was to investigate the correlation between the haematological toxicity observed in patients treated with craniospinal irradiation, and the dose distribution in normal tissue, specifically the occurrence of large volumes exposed to low dose.

MATERIALS AND METHODS

Twenty adult male patients were included in this study; eight treated with helical tomotherapy (HT), and twelve with three-dimensional conformal radiation therapy. The relative volume of red bone marrow and body that was exposed to low dose (i.e. the so-called dose bath) was evaluated and correlated with nadir blood values during treatment, i.e. the severity of anaemia, leukopaenia, and thrombocytopaenia. The correlation was tested for different dose levels representing the dose bath using the Pearson product-moment correlation method.

RESULTS

We found a significant correlation between the volume of red bone marrow exposed to low dose and the severity of thrombocytopaenia during treatment. Furthermore, for the HT patients, a significant correlation was found between the relative volume of the body exposed to low dose and the severity of anaemia and leukopenia.

CONCLUSIONS

The severity of haematological toxicity correlated with the fraction of red bone marrow or body that was exposed to low dose.