[In vitro radiosensitivity of skin fibroblasts can identify a group of patients with complications in various health tissues after radiotherapy].

PURPOSE: A retrospective study of the in vitro radiosensitivity of skin fibroblasts derived from two groups of patients treated by definitive radiotherapy for a variety of tumors who either displayed or did not display severe complications. PATIENTS AND METHODS: Seven radiotherapy patients were selected: three were treated for head and neck, prostate and non-Hodgkin lymphoma tumors, and did not develop any significant complications (control group); four patients were treated for bladder, thyroid, head and neck and anal canal tumors and developed serious acute and especially late reactions (hypersensitive group). Primary cell cultures of skin fibroblasts were established and their radiosensitivity studied by the clonogenic assay after exposing to single radiation doses ranging between 1 and 8 Gy. RESULTS: The survival fraction at 2 Gy (SF2) ranged from 0.27 to 0.38, with a mean of 0.33 for the control group, and from 0.10 to 0.20 with a mean of 0.17 for the hypersensitive group. The Mann-Whitney non-parametric test showed that the difference between the two means was statistically significant (p = 0.03). CONCLUSION: The data are in favor of a correlation between the radiosensitivity of patients' fibroblasts and the reactions of different normal tissues to radiotherapy. This association supports the use of the clonogenic survival, or a surrogate test, as a predictive assay. The multiplicity of normal tissues and organs implicated in this association suggests the existence of genetic factors that determine, at least in part, the radiosensitivity of target cells involved in the expression of normal tissues complications following radiotherapy.