Correlation between normal tissue complications and in vitro radiosensitivity of skin fibroblasts derived from radiotherapy patients treated for variety of tumors

Purpose: To assess the relationship between fibroblast intrinsic radiosensi tivity irt vitro and late reactions of normal tissues in patients treated b y definitive radiotherapy for variety of tumors. Patients and Methods: Ten patients were selected for this study. They were treated by radical radiotherapy for variety of tumors, including non-Hodgki n's lymphoma, prostate, glottic larynx, anal canal, cervix, bladder, thyroi d gland, and tonsil pillar. Five patients did not develop any significant l ate reactions (normally sensitive group, NS), The other five developed Late complications in different normal tissues and organs that proved to be fat al in one patient (clinically hyper-sensitive group, HS). Fibroblast cultur es were established from punch skin biopsy and radiosensitivity in vitro wa s measured. The survival fraction at 2 Gy (SF2) was calculated and compared between the two groups. Results: SF2 ranged between 0.10 and 0.38 with a mean of 0.24. The mean SF2 for each of the NS and the HS groups were 0.31 and 0.17, respectively. The non-parametric rank test of Mann-Whitney shows that the difference between the two groups is statistically significant (p = 0.01), Conclusion: This study indicates that the in vitro radiosensitivity of skin fibroblasts is correlated with late complications in different organs and normal tissues following radiotherapy for variety of tumors. It also lends support to the existence of a common genetic component determining the radi osensitivity of cells targeted by the late effects of ionizing radiation. ( C) 2000 Elsevier Science Inc.