The leukocyte apoptosis assay : a clinical predictor of radiosensitivity?

Abstract

The main objective of radiotherapy is to completely eradicate tumours while preserving the integrity of the normal surrounding tissue. The severity of normal tissue reactions varies considerably amongst individuals. Following the same treatment regime for individuals with identical tumours in terms of location, pathology and size might result in adverse tissue reactions for some while others may experience no adverse reactions. Based on this principle some individuals who are more radiosensitive than others are receiving beyond normal tissue tolerance doses while others, who are more radioresistant, receive sub-tolerance doses. These differences in response to radiation are a concern for both the patient and the oncologist. For these reasons it is essential to predict individual responses to radiotherapy in order to optimise the treatment regime for each patient. The development of predictive assays for normal tissue reactions are in the early stages and not routinely used in laboratories. Qualities of a predictive assay should include the capacity to distinguish between small changes in individual radiosensitivity. These assays should also be easy and quick to perform so that it can be employed during the initial treatment planning phase for therapy. Also, the assay should be inexpensive enough to be used on a daily basis in the clinic.