Comparison of chromosomal radiosensitivity of normal cells with and without HRS-like response and normal tissue reactions in patients with cervix cancer.

Purpose: In our previous study, using the micronucleus (MN) assay, the low- and high-dose radiation response of fibroblasts and keratinocytes from cancer patients was assessed. We reported that a hyper-radiosensitivity (HRS)-like phenomenon was observed for fibroblasts of two and keratinocytes of four of the 40 patients studied. In this paper, we report the comparison of these in vitro results and normal tissue reactions in patients with cervix cancer and answer the question of the predictive value of the MN assay.

Materials And Methods: Of the 40 patients with cervix cancer whose cells were previously studied in vitro, 32 received radiotherapy. The treated group included two patients with HRS-like positive fibroblasts and four patients with HRS-like positive keratinocytes. In 26 patients both types of cells were HRS-like negative. The in vitro results (MN induction measured in patients' fibroblasts and keratinocytes after in vitrogamma-irradiation with doses ranging from 0.05-4 Gy) were compared with the maximum grade of acute and late reactions.

Results: Five of the six patients whose cells demonstrated low-dose chromosomal hypersensitivity in vitro, did not suffer from any mild or severe side effects after radiotherapy. Although individual variations in the grade scores of normal-tissue reactions were observed in cancer patients, no significant relationship was found between MN induction, either in fibroblasts or keratinocytes, and acute and late effects.

Conclusion: Since the MN assay showed no predictive value, it is rather impossible that the severe late complication observed in one of the six HRS-like positive patients reflects her low-dose chromosomal hypersensitivity in vitro.