Keywords: radiotherapy, predictive assays, late irradiation morbidity, CD4, CD8 lymphocytes, apoptosis, Pentoxifylline, low radiation, radiosensitivity prediction, fibroblasts, tumour biopsies
New trends in the management of late radiation morbidity
Currently, no reliable methods and no suitable marker profile exist that could predict radiosensitivity in patients. This paper describes the irradiation response of lymphocytes, fibroblasts and tumour biopsies cultured in vitro, clonogenic survival at 2 Gy (SF2), chromosomal aberrations, and CD4 and CD8 lymphocyte apoptosis. The results, and other accumulating evidence, strongly suggest that lymphocytes are a superior test specimen for predictive analysis. A variety of drugs and drug mixtures, especially Pentoxifylline and vitamin E, modulate the irradiation response and can ameliorate late morbidity. The conclusion is that agents that modulate the inflammatory and fibrogenic reactions are effective in suppressing late irradiation morbidity. The latest clinical data show that irradiation-induced apoptotic propensity in CD4 and CD8 lymphocytes can predict late grade 2 and grade 3 irradiation toxicity.